start bastext 1025
start tok64 d64-H1nPxr
1 RUN00010
10 GOSUB63100:sn$="00100"
20 POKE53281,15:POKE53280,12:PRINT"{black}":GOSUB55000
100 POKE53281,15:POKE53280,12:PRINT"{black}":PRINT"{clear}{space*11}{reverse on}{blue}micros'n'chips-1"
101 PRINT"{red}{cm a}{sh asterisk*37}{cm s}":GOSUB63100
102 PRINT"{sh -} {reverse on}{blue}{space*9}address decoding{space*10}{red}{reverse off} {sh -}":ms$="ponzotutor"
103 PRINT"{red}{cm z}{sh asterisk*37}{cm x}{black}":GOSUB63200
104 ms$=" welcome! ":GOSUB63200:POKE53280,15
105 PRINT"{home}{down*10}Qnote{down}{left*4}{cm u*4}{up}:hit the @-key at any"
106 PRINT"{down}{space*6}time to return to an":PRINT"{down}{space*6}earlier section{.*3}":GOSUB50000
1000 GOSUB63100:REM micros-1
1001 sn$="01{0*3}"
1005 PRINT"{clear}{down}Qthe {reverse on}heart{reverse off} of a micro is the"
1010 PRINT"{down} {reverse on}m{reverse off}icro {reverse on}p{reverse off}rocessing {reverse on}u{reverse off}nit or {reverse on}mpu{reverse off}."
1015 PRINT"{down} on the commodore 64 it's a 40-pin"
1020 PRINT"{down} chip called a {reverse on*2}6510{reverse off}."
1025 PRINT"{down} {cm a}{sh asterisk*10}{cm s}"
1030 PRINT" {sh -}{reverse on}{space*3}6510{space*3}{reverse off}{sh -} {arrow left}chip"
1035 PRINT" {cm z}{sh asterisk*10}{cm x}"
1036 PRINT"{down}Qon earlier commodore micros":PRINT"{down} it's a {reverse on}6502{reverse off}."
1040 ms$="hit a key!":GOSUB63200:GOSUB50000
1045 PRINT"{clear}{down}Qthe {reverse on}6510{reverse off} can execute"
1050 PRINT"{down} some 56 instructions"
1055 PRINT"{down} such as {reverse on}add{reverse off},{reverse on}subract{reverse off}"
1060 PRINT"{down} etc.etc.(all pretty easy).."
1065 PRINT"{down} each instruction":PRINT"{down} executed is stored"
1070 PRINT"{down} in memory,so the {reverse on}mpu{reverse off}"
1075 PRINT"{down} must be able to {reverse on}read":PRINT"{down} these instructions"
1080 PRINT"{down} from memory.":GOSUB50000
1085 PRINT"{clear}{down}Qthe {reverse on}6510{reverse off} must also"
1090 PRINT"{down} be able to store data"
1095 PRINT"{down} in memory ({reverse on}write{reverse off})."
1100 PRINT"{down} communication with":PRINT"{down} memory is via :"
1105 PRINT"{down} an {reverse on}address bus{reverse off}"
1110 PRINT"{down} and a {reverse on}data bus{reverse off}.{down}":GOSUB50000
1115 PRINT"{cm a}{sh asterisk*4}{cm s}"
1120 PRINT"{sh -}{Q*3} {cm z}{sh asterisk}{cm s}{space*2}{arrow left}bus(?)"
1125 PRINT"{cm z}UI{sh asterisk*3}UI"
1130 PRINT" JK{space*3}JK":FORt=1TO1000:NEXT
1135 PRINT"{clear}{down}Qto 16{down}{left*2}{cm u*2}{up} pins of"
1140 PRINT"{down} the {reverse on}6510{reverse off} are "
1145 PRINT"{down} connected wires":PRINT"{down} called the":PRINT"{down} {reverse on}address bus{reverse off}."
1150 PRINT"{down}Qto another 8{down}{left}{cm u}{up} pins":PRINT"{down} are connected"
1155 PRINT"{down} wires called the"
1160 PRINT"{down} {reverse on}data bus{reverse off}.":GOSUB50000
1165 PRINT"{clear}{down*6}Qthe 'voltage' on"
1170 PRINT"{down} each or these 24"
1175 PRINT"{down} wires may be 'high'"
1180 PRINT"{down} or 'low'{.*3}we'll":PRINT"{down} say {reverse on}1{reverse off} or {reverse on}0{reverse off}.":ms$="hi={reverse on}1{reverse off} lo={reverse on}0{reverse off}"
1185 GOSUB63200:GOSUB50000:GOSUB1455:GOSUB1480:GOSUB50000
1190 PRINT"{clear}{down}Qsince each of 16"
1195 PRINT"{down} {reverse on} address bus{reverse off} wires":PRINT"{down} may be {reverse on}1{reverse off} or {reverse on}0{reverse off}"
1200 PRINT"{down} there are 2^16=65536"
1205 PRINT"{down} possible 'addresses'":PRINT"{down}{sh space}ranging from"
1210 PRINT"{down} 0 to 65535."
1215 PRINT"{down} 2^10={reverse on}1k{reverse off} so we have"
1220 PRINT"{down} 2^16={reverse on}64k{reverse off} addresses"
1225 PRINT"{down} with a 16 bit {reverse on}bus{reverse off}.":ms$="{space*2}a c64!":GOSUB63200:GOSUB50000
1230 PRINT"{clear}{down*4}Qsimilarly there are"
1235 PRINT"{down} 2^8=256 possible"
1240 PRINT"{down} {reverse on}1{reverse off}/{reverse on}0{reverse off} combinations"
1245 PRINT"{down} on the 8 bit {reverse on}data bus"
1250 PRINT"{down} so any number: 0-255"
1255 PRINT"{down} may be on this bus.":ms$="data=0-255":GOSUB63200:GOSUB50000
1260 PRINT"{clear}{down}Qsuppose we perform":PRINT"{down} {reverse on}poke m,n"
1265 PRINT"{down} then:0<=m<=65535"
1270 PRINT"{down} and{space*2}0<=n<=255.":PRINT"{down}Qconsider:"
1275 PRINT"{down} {reverse on}poke 1234,5":PRINT"{down} the {reverse on}6510{reverse off} puts"
1280 PRINT"{down} the number '1234'"
1285 PRINT"{down} on the {reverse on}address bus"
1290 PRINT"{down} and the number '5'"
1295 PRINT"{down} on the {reverse on}data bus{reverse off}.":GOSUB50000
1300 PRINT"{clear}{down*5}Qthese numbers must"
1305 PRINT"{down} of course be in"
1310 PRINT"{down} {reverse on}binary{reverse off}!!":GOSUB50000:GOSUB1455
1315 a$="{0*5}10011010010":d$="{0*5}101":GOSUB1515:GOSUB1525:GOSUB50000
1320 PRINT"{clear}{down*5}Qwhen executing:"
1325 PRINT"{down} {reverse on}poke 1234,5":PRINT"{down} the {reverse on}6510{reverse off} expects"
1330 PRINT"{down} the memory at loc'n"
1335 PRINT"{down} '1234' to accept":PRINT"{down} the number '5'"
1340 PRINT"{down} which is on the":PRINT"{down} {reverse on}data bus{reverse off}!":GOSUB50000
1341 t$="memory":GOSUB63000
1345 PRINT"{down}Q'memory' in a micro"
1350 PRINT"{down} is just more {reverse on}chips{reverse off}!"
1355 PRINT"{down} they come in various"
1360 PRINT"{down} sizes but we suppose"
1365 PRINT"{down} our memory chips each"
1370 PRINT"{down} contain {reverse on}2k{reverse off} bytes."
1375 PRINT"{down} (each {reverse on}byte{reverse off} being"
1380 PRINT"{down} 8 binary {reverse on}bits{reverse off}).":GOSUB50000
1385 PRINT"{clear}{down}Qone{down}{left*3}{cm u*3}{up} of these memory"
1390 PRINT"{down} chips should accept"
1395 PRINT"{down} {reverse on}data{reverse off} from the {reverse on}bus{reverse off}"
1400 PRINT"{down} when the {reverse on}address{reverse off} is"
1405 PRINT"{down} 0 to 2047, and another{down}{left*7}{cm u*7}{up}"
1410 PRINT"{down} chip when the {reverse on}address"
1415 PRINT"{down} is from 2048 to 4096,"
1420 PRINT"{down} and another{down}{left*7}{cm u*7}{up}"
1425 PRINT"{down} when the {reverse on}address"
1430 PRINT"{down} is from 4096 to 6143,"
1435 PRINT"{down} etc.etc.etc.":ms$=" 2k=2048":GOSUB63200:GOSUB50000
1440 t$="{space*5}how?{space*5}":GOSUB63000:ms$="i give up!":GOSUB63200:GOSUB50000
1445 GOTO2000
1455 PRINT"{clear}";:FORi=1TO16
1460 PRINT"{sh -}{reverse on}{space*3}{reverse off}{cm q}{sh asterisk*2} {sh asterisk} {sh asterisk} {sh asterisk}":NEXT
1465 FORi=1TO7
1470 PRINT"{sh -}{reverse on}{space*3}{reverse off}{cm q}{sh asterisk*6}":NEXT
1471 PRINT"{sh -}{reverse on}{space*3}{reverse off}{cm q}{sh asterisk*6}{home}"
1475 PRINT"{home}{down*8}{right*2}6{down}{left}5{down}{left}1{down}{left}0":RETURN
1480 PRINT"{home}{down*8}{right*13}16 wire"
1485 PRINT"{down}{right*13}{reverse on}address"
1490 PRINT"{down}{right*13}{space*2}bus"
1495 PRINT"{down*4}{right*12}8 wire"
1500 PRINT"{down}{right*12} {reverse on}data"
1505 PRINT"{down}{right*12} bus"
1510 PRINT"{home}{down*8}{right*2}6{down}{left}5{down}{left}1{down}{left}0":RETURN
1515 PRINT"{home}{right*13}";
1520 FORi=1TOLEN(a$):PRINTMID$(a$,i,1)"{down}{left}";:NEXT:RETURN
1525 PRINT"{home}{down*16}{right*11}";
1530 FORi=1TOLEN(d$):PRINTMID$(d$,i,1)"{down}{left}";:NEXT:RETURN
1545 RETURN
2000 GOSUB63100:REM micros-2
2001 sn$="02{0*3}":t$="address decoding":GOSUB63000
2005 PRINT"{down}Qif our memory is"
2010 PRINT"{down} in 2k chips,then"
2015 PRINT"{down} each chip will"
2020 PRINT"{down} have an associated"
2025 PRINT"{down} {reverse on}address decoder"
2030 PRINT"{down} circuit which will"
2035 PRINT"{down} constantly check"
2040 PRINT"{down} the {reverse on}address bus{reverse off}"
2045 PRINT"{down} to see if the {reverse on}6510"
2050 PRINT"{down} wants to talk to {reverse on}it{reverse off}!":GOSUB50000
2055 PRINT"{clear}{down}Qfor our example:"
2060 PRINT"{down} {reverse on}poke 1234,5"
2065 PRINT"{down} the very first{down}{left*5}{cm u*5}{up} 2k"
2070 PRINT"{down} chip should respond."
2075 PRINT"{down} (any address from"
2080 PRINT"{down} 0 to 2047..remember?)."
2085 PRINT"{down} this chip's {reverse on}decoder{reverse off}"
2090 PRINT"{down} must recognize that"
2095 PRINT"{down} '1234' lies in the"
2100 PRINT"{down} range (0,2047) and"
2105 PRINT"{down} {reverse on}tell the memory chip{reverse off}."
2110 ms$="wake up!":GOSUB63200:GOSUB50000:GOSUB2440:GOSUB50000
2115 PRINT"{clear}{down}Qif the {reverse on}address{reverse off} is"
2120 PRINT"{down} in (2048,4095) then"
2125 PRINT"{down} the next{down}{left*4}{cm u*4}{up} {reverse on}decoder"
2130 PRINT"{down} must send a signal"
2135 PRINT"{down} to the 2nd{down}{left*3}{cm u*3}{up} chip."
2140 PRINT"{down} etc.etc."
2145 PRINT"{down}Qthese {reverse on}chip select{reverse off}"
2150 PRINT"{down} signals are usually"
2155 PRINT"{down} '0'. how are"
2160 PRINT"{down} they generated??":ms$="i give up!":GOSUB63200:GOSUB50000
2165 t$="gates 'n' such":GOSUB63000
2170 PRINT"{down*3}Qthere are three"
2175 PRINT"{down} (among others)"
2180 PRINT"{down} standard electronic"
2185 PRINT"{down} circuits called"
2190 PRINT"{down}{space*5}{reverse on}gates{reverse off}."
2195 PRINT"{down}Qeach accepts one or"
2200 PRINT"{down} more input wires"
2205 PRINT"{down} and delivers one"
2210 PRINT"{down} output signal."
2215 GOSUB50000
2220 t$="and gates":GOSUB63000
2225 PRINT"{down*2}Qoutput=1 only if"
2230 PRINT"{down} x=1 and{down}{left*3}{cm u*3}{up} y=1."
2235 GOSUB2550:PRINT"{down*3}{right*4}"ag$
2240 PRINT"{down*4}Qthis is a"
2245 PRINT"{down} 2-input {reverse on}and{reverse off} gate."
2250 PRINT" {cm u*7}":ms$=" x {reverse on}and{reverse off} y":GOSUB63200:GOSUB50000
2255 PRINT"{clear}{down*5}Qin an {reverse on}and{reverse off} gate"
2260 PRINT"{down} output=1 only{down}{left*4}{cm u*4}"
2265 PRINT" if {reverse on}all{reverse off} inputs=1.":GOSUB50000
2270 t$="or gates":GOSUB63000
2275 PRINT"{down*2}Qoutput=1 if"
2280 PRINT"{down} x=1 or{down}{left*2}{cm u*2}{up} y=1."
2285 PRINT"{down*3}{right*4}"og$
2290 PRINT"{down*4}Qthis is a "
2295 PRINT"{down} 2-input {reverse on}or{reverse off} gate."
2300 PRINT" {cm u*7}":ms$=" x {reverse on}or{reverse off} y":GOSUB63200:GOSUB50000
2305 PRINT"{clear}{down*5}Qin an {reverse on}or{reverse off} gate"
2310 PRINT"{down} output=0 only{down}{left*4}{cm u*4}"
2315 PRINT" if {reverse on}all{reverse off} inputs=0.":GOSUB50000
2320 t$="not gate=inverter":GOSUB63000
2325 PRINT"{down*2}Qoutput=1 if x=0."
2330 PRINT"{down*2} output=0 if x=1."
2335 PRINT"{down*3}{right*4}"ng$
2340 PRINT"{down}Qthe output is always"
2345 PRINT"{down} the 'complement' of"
2350 PRINT"{down} the input.":ms$=" {reverse on}not{reverse off} x":GOSUB63200:GOSUB50000
2355 PRINT"{clear}{down}Qa typical chip may"
2360 PRINT"{down} contain several gates."
2370 PRINT"{down} the '7400' is a"
2375 PRINT"{down} 14 pin chip with"
2380 PRINT"{down} four 2-input {reverse on}nand{reverse off}s."
2385 PRINT"{down} (a {reverse on}nand{reverse off} is an"
2390 PRINT"{down} {reverse on}and{reverse off} followed by"
2395 PRINT"{down} a {reverse on}not{reverse off}{.*3}an"
2400 PRINT"{down} 'inverted and').":ms$="nand gate!":GOSUB63200:GOSUB50000
2405 PRINT"{clear}{down}Qto build a {reverse on}decoder{reverse off}"
2410 PRINT"{down} to recognize when the"
2415 PRINT"{down} {reverse on}address bus{reverse off} has an"
2420 PRINT"{down} address in (0,2047)"
2425 PRINT"{down} ..and provide a"
2430 PRINT"{down} {reverse on}chip select{reverse off} to a"
2435 PRINT"{down} memory chip{.*3}":PRINT"{down*2}{.*3}how??{.*3}":ms$="how? how?"
2436 GOSUB63200:GOSUB50000:GOTO3000
2440 PRINT"{clear} {sh asterisk*2}Q{sh asterisk*11}"
2441 PRINT" {sh asterisk*2}{sh +}Q{sh asterisk*9}"
2442 PRINT" {sh asterisk*2}{sh +*2}Q{sh asterisk*8}"
2443 PRINT" {sh asterisk*2}{sh +*3}Q{sh asterisk*7}"
2444 PRINT" {sh asterisk*2}{sh +*4}Q{sh asterisk*6}"
2445 PRINT" ..{sh -*4}{.*7}"
2446 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*2}Q{sh asterisk*3}"
2447 PRINT"{space*2}{cm a}{cm e*8}{cm s}"
2448 PRINT"{space*2}{sh -}decoder1{sh -}"
2449 PRINT"{space*2}{cm z}{sh asterisk*4}{cm r}{sh asterisk*3}{cm x}"
2450 PRINT"{space*2}{cm a}{sh asterisk*4}{cm e}{sh asterisk*3}{cm s}"
2451 PRINT"{space*2}{sh -}memory 1{sh -}"
2452 PRINT"{space*2}{cm z}{cm r*8}{cm x}"
2453 PRINT" {sh asterisk*2}Q{sh +*7}{sh asterisk*3}"
2454 PRINT" {sh asterisk*3}Q{sh +*6}{sh asterisk*3}"
2455 PRINT" {sh asterisk*4}Q{sh +*5}{sh asterisk*3}"
2456 PRINT" {sh asterisk*5}Q{sh +*4}{sh asterisk*3}"
2457 PRINT" {sh asterisk*6}Q{sh +*3}{sh asterisk*3}"
2458 PRINT" {sh asterisk*7}Q{sh +*2}{sh asterisk*3}"
2459 PRINT" {sh asterisk*8}Q{sh +}{sh asterisk*3}"
2460 PRINT" {sh asterisk*9}Q{sh asterisk*3}"
2465 s$="{right*14}"
2470 ms$="{space*2}first":GOSUB63200:GOSUB50000
2500 PRINT"{home}"s$"{sh asterisk}Q{sh asterisk*11}"
2501 PRINTs$"{sh asterisk}{sh +}Q{sh asterisk*9}"
2502 PRINTs$"{sh asterisk}{sh +*2}Q{sh asterisk*8}{reverse on}address"
2503 PRINTs$"{sh asterisk}{sh +*3}Q{sh asterisk*7}{reverse on}bus{space*4}"
2504 PRINTs$"{sh asterisk}{sh +*4}Q{sh asterisk*6}"
2505 PRINTs$".{sh -*4}{.*8}"
2506 PRINTs$"{sh asterisk}{sh +*5}{sh asterisk*2}Q{sh asterisk*3}"
2507 PRINTs$"{cm a}{cm e*8}{cm s}"
2508 PRINTs$"{sh -}decoder2{sh -}"
2509 PRINTs$"{cm z}{sh asterisk*4}{cm r}{sh asterisk*3}{cm x}"
2510 PRINTs$"{cm a}{sh asterisk*4}{cm e}{sh asterisk*3}{cm s}"
2511 PRINTs$"{sh -}memory 2{sh -}"
2512 PRINTs$"{cm z}{cm r*8}{cm x}"
2513 PRINTs$"{sh asterisk}Q{sh +*7}{sh asterisk*3}"
2514 PRINTs$"{sh asterisk*2}Q{sh +*6}{sh asterisk*3}"
2515 PRINTs$"{sh asterisk*3}Q{sh +*5}{sh asterisk*3}"
2516 PRINTs$"{sh asterisk*4}Q{sh +*4}{sh asterisk*3}{reverse on}data"
2517 PRINTs$"{sh asterisk*5}Q{sh +*3}{sh asterisk*3}{reverse on}bus "
2518 PRINTs$"{sh asterisk*6}Q{sh +*2}{sh asterisk*3}"
2519 PRINTs$"{sh asterisk*7}Q{sh +}{sh asterisk*3}"
2520 PRINTs$"{sh asterisk*8}Q{sh asterisk*3}"
2525 ms$="{space*3}next":GOSUB63200:GOSUB50000:ms$="and so on":GOSUB63200
2545 RETURN
2550 ag$="{cm a}{sh asterisk*4}{cm s}{down}{left*8}x{sh asterisk}{cm w}{reverse on}and {reverse off}{sh -}{down}{left*8}y{sh asterisk}{cm w}{reverse on}gate{reverse off}{cm q}{sh asterisk*2}output"
2555 ag$=ag$+"{down}{left*14}{cm z}{sh asterisk*4}{cm x}"
2560 og$="{cm a}{sh asterisk*4}{cm s}{down}{left*8}x{sh asterisk}{cm w}{reverse on} or {reverse off}{sh -}{down}{left*8}y{sh asterisk}{cm w}{reverse on}gate{reverse off}{cm q}{sh asterisk*2}output"
2565 og$=og$+"{down}{left*14}{cm z}{sh asterisk*4}{cm x}"
2570 ng$="{cm a}{sh asterisk*4}{cm s}{down}{left*8}{space*2}{sh -}{reverse on}not {reverse off}{sh -}{down}{left*8}x{sh asterisk}{cm w}{reverse on}gate{reverse off}{cm q}{sh asterisk*2}output"
2575 ng$=ng$+"{down}{left*14}{cm z}{sh asterisk*4}{cm x}"
2580 RETURN
2595 RETURN
3000 GOSUB63100:REM micros-3
3001 sn$="03{0*3}":t$="decoding":GOSUB63000
3030 PRINT" {sh asterisk*6}Q{sh asterisk}"
3035 PRINT" {sh asterisk*5}Q{sh +}{sh asterisk}"
3040 PRINT" {sh asterisk*4}Q{sh +*2}{sh asterisk}"
3045 PRINT" {sh asterisk*3}Q{sh +*3}{sh asterisk}"
3050 PRINT" {sh asterisk*2}Q{sh +*4}{sh asterisk}"
3055 PRINT"{space*3}{sh -*5} {cm a}{sh asterisk*2}{cm s}"
3060 PRINT"{space*3}{sh -*4}{cm z}{sh asterisk}{cm w}{space*2}{sh -}"
3065 PRINT"{space*3}{sh -*3}{cm z}{sh asterisk*2}{cm w}{space*2}{sh -}"
3070 PRINT"{space*3}{sh -*2}{cm z}{sh asterisk*3}{cm w}{reverse on}or{reverse off}{cm q}{sh asterisk}chip"
3075 PRINT"{space*3}{sh -}{cm z}{sh asterisk*4}{cm w}{space*2}{sh -} select"
3080 PRINT"{space*3}{cm z}{sh asterisk*5}{cm w}{space*2}{sh -}"
3085 PRINT"{space*9}{cm z}{sh asterisk*2}{cm x}"
3090 PRINT"{down}Qa 5-input {reverse on}or{reverse off} gate"
3095 PRINT"{down} connected to the"
3100 PRINT"{down} top 5 bits of"
3105 PRINT"{down} the address bus.."
3110 GOSUB50000
3115 PRINT"{clear}{down} 0{sh asterisk*5}Q{sh asterisk}"
3120 PRINT" 0{sh asterisk*4}Q{sh +}{sh asterisk}"
3125 PRINT" 0{sh asterisk*3}Q{sh +*2}{sh asterisk}"
3130 PRINT" 0{sh asterisk*2}Q{sh +*3}{sh asterisk}"
3135 PRINT" 0{sh asterisk}Q{sh +*4}{sh asterisk}"
3140 PRINT"{space*3}{sh -*5} {cm a}{sh asterisk*2}{cm s}"
3145 PRINT"{space*3}{sh -*4}{cm z}{sh asterisk}{cm w}{space*2}{sh -}"
3150 PRINT"{space*3}{sh -*3}{cm z}{sh asterisk*2}{cm w}{space*2}{sh -}"
3155 PRINT"{space*3}{sh -*2}{cm z}{sh asterisk*3}{cm w}{reverse on}or{reverse off}{cm q}{sh asterisk}{reverse on}0"
3160 PRINT"{space*3}{sh -}{cm z}{sh asterisk*4}{cm w}{space*2}{sh -}"
3165 PRINT"{space*3}{cm z}{sh asterisk*5}{cm w}{space*2}{sh -}"
3170 PRINT"{space*9}{cm z}{sh asterisk*2}{cm x}"
3175 PRINT"{down} ..will give a {reverse on}0"
3180 PRINT"{down} output only if"
3185 PRINT"{down} all{down}{left*3}{cm u*3}{up} address bits={reverse on}0":ms$="0{reverse on}or{reverse off}0{reverse on}or{reverse off}0=0"
3186 GOSUB63200:GOSUB50000
3190 PRINT"{clear}{down}Qnote that the"
3195 PRINT"{down} first 2k memory"
3200 PRINT"{down} should respond to"
3205 PRINT"{down} addresses from"
3210 PRINT"{down} {0*4} {0*4} {0*4} {0*4}"
3215 PRINT"{down} to"
3220 PRINT"{down} {0*4} 0{1*3} {1*4} {1*4}"
3225 PRINT"{down} (in binary)."
3230 PRINT"{down} see! the top 5"
3235 PRINT"{down} bits are all '0'!":GOSUB50000
3240 PRINT"{clear}{down}hence:"
3245 PRINT" {sh asterisk*6}Q{sh asterisk}"
3250 PRINT" {sh asterisk*5}Q{sh +}{sh asterisk}"
3255 PRINT" {sh asterisk*4}Q{sh +*2}{sh asterisk}"
3260 PRINT" {sh asterisk*3}Q{sh +*3}{sh asterisk}"
3265 PRINT" {sh asterisk*2}Q{sh +*4}{sh asterisk}"
3270 PRINT"{space*3}{sh -*5} {cm a}{sh asterisk*2}{cm s}"
3275 PRINT"{space*3}{sh -*4}{cm z}{sh asterisk}{cm w}{space*2}{sh -}"
3280 PRINT"{space*3}{sh -*3}{cm z}{sh asterisk*2}{cm w}{space*2}{sh -}"
3285 PRINT"{space*3}{sh -*2}{cm z}{sh asterisk*3}{cm w}{reverse on}or{reverse off}{cm q}{sh asterisk}chip"
3290 PRINT"{space*3}{sh -}{cm z}{sh asterisk*4}{cm w}{space*2}{sh -} select"
3295 PRINT"{space*3}{cm z}{sh asterisk*5}{cm w}{space*2}{sh -}"
3300 PRINT"{space*9}{cm z}{sh asterisk*2}{cm x}"
3305 PRINT"{down} will {reverse on}decode{reverse off} for"
3310 PRINT"{down} the first 2k of"
3315 PRINT"{down} memory!":ms$="62k to go!":GOSUB63200:GOSUB50000
3320 PRINT"{clear}{down}Qthe next 2k bytes"
3325 PRINT"{down} go from"
3330 PRINT"{down} {0*4} 1{0*3} {0*4} {0*4}"
3335 PRINT"{down} to"
3340 PRINT"{down} {0*4} {1*4} {1*4} {1*4}"
3345 PRINT"{down}Qa workable {reverse on}decoder"
3350 PRINT"{down} might be{.*3}":GOSUB50000
3355 PRINT"{clear}{down} {sh asterisk*6}Q{sh asterisk}"
3360 PRINT" {sh asterisk*5}Q{sh +}{sh asterisk}"
3365 PRINT" {sh asterisk*4}Q{sh +*2}{sh asterisk}"
3370 PRINT" {sh asterisk*3}Q{sh +*3}{sh asterisk}"
3375 PRINT" {sh asterisk*2}Q{sh +*4}{sh asterisk}"
3380 PRINT"{space*3}{sh -*5} {cm a}{sh asterisk*2}{cm s}"
3385 PRINT"{space*3}{sh -*4}{cm z}{sh asterisk}{cm w}{space*2}{sh -}"
3390 PRINT"{space*3}{sh -*3}{cm z}{sh asterisk*2}{cm w}{space*2}{sh -}"
3395 PRINT"{space*3}{sh -*2}{cm z}{sh asterisk*3}{cm w}{reverse on}or{reverse off}{cm q}{sh asterisk}chip"
3400 PRINT"{space*3}{sh -}{cm z}{sh asterisk*4}{cm w}{space*2}{sh -} select"
3405 PRINT"{space*3}{sh -}{cm a}{sh asterisk*3}{cm s}{sh -}{space*2}{sh -}"
3410 PRINT"{space*3}{cm z}{cm w}{reverse on}not{reverse off}{cm q}{cm w}{space*2}{sh -}"
3415 PRINT"{space*4}{cm z}{sh asterisk*3}{cm x}{cm z}{sh asterisk*2}{cm x}"
3420 ms$="and so on":GOSUB63200:GOSUB50000
3425 PRINT"{clear}{down}Qnow let's return to"
3430 PRINT"{down} {reverse on}poke1234,5{reverse off}."
3435 PRINT"{down} the {reverse on}6510{reverse off} will put"
3440 PRINT"{down} '1234' on the"
3445 PRINT"{down} {reverse on}address bus{reverse off} and"
3450 PRINT"{down} '5' on the {reverse on}data bus"
3455 PRINT"{down} (in binary,of course)"
3460 PRINT"{down} and the first {reverse on}decoder"
3465 PRINT"{down} will 'wake up' the"
3470 PRINT"{down} first 2k memory chip.":GOSUB50000
3475 PRINT"{clear}{down}Qif we execute"
3480 PRINT"{down} {reverse on}x=peek(1234){reverse off}"
3485 PRINT"{down} then the {reverse on}6510{reverse off}"
3490 PRINT"{down} will also{down}{left*4}{cm u*4}{up} put"
3495 PRINT"{down} address '1234' on"
3500 PRINT"{down} the bus{.*4}and the"
3505 PRINT"{down} same 2k chip will"
3510 PRINT"{down} respond.":GOSUB50000
3515 PRINT"{clear}{down}Qfor {reverse on}poke 1234,5"
3520 PRINT"{down} we want to {reverse on}write"
3525 PRINT"{down} to memory."
3530 PRINT"{down} for {reverse on}x=peek(1234)"
3535 PRINT"{down} we want to {reverse on}read"
3540 PRINT"{down} from memory."
3545 PRINT"{down} how does the memory"
3550 PRINT"{down} chip know whether"
3554 PRINT"{down} the {reverse on}6510{reverse off} wants"
3555 PRINT"{down} to {reverse on}read{reverse off} or {reverse on}write{reverse off}?":GOSUB50000
3560 PRINT"{clear}{down}Qfor {reverse on}read{reverse off},the chip{down}{left*4}{cm u*4}"
3565 PRINT" must put a number"
3570 PRINT"{down} on the {reverse on}data bus{reverse off}."
3575 PRINT"{down}Qfor {reverse on}write{reverse off},the"
3580 PRINT"{down} 6510{down}{left*4}{cm u*4}{up} puts the byte"
3585 PRINT"{down} on the {reverse on}data bus{reverse off}!"
3590 PRINT"{down}Qfortunately, the"
3595 PRINT"{down} {reverse on}6510{reverse off} provides a"
3600 PRINT"{down} {reverse on}read/write{reverse off} signal"
3605 PRINT"{down} from one of it's"
3610 PRINT"{down} 40 pins.":GOSUB50000
3615 GOSUB3640:PRINT"{up*10}{right*11}{cm q}{arrow left}{sh asterisk*2}";:FORi=1TO10:PRINT"r/w{left*3}";
3620 FORj=1TO100:NEXT:PRINT"{reverse on}r/w{reverse off}{left*3}";:FORj=1TO100:NEXT:NEXT
3625 ms$="very nice!":GOSUB63200:GOSUB50000
3630 GOTO4000
3640 PRINT"{clear}{down} {sh asterisk*2}Q{sh asterisk*11}"
3645 PRINT" {sh asterisk*2}{sh +}Q{sh asterisk*9}"
3650 PRINT" {sh asterisk*2}{sh +*2}Q{sh asterisk*8}{reverse on}address"
3655 PRINT" {sh asterisk*2}{sh +*3}Q{sh asterisk*7}{reverse on}bus{space*4}"
3660 PRINT" {sh asterisk*2}{sh +*4}Q{sh asterisk*6}"
3665 PRINT" ..{sh -*4}{.*8}"
3670 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*2}Q{sh asterisk*3}"
3675 PRINT"{space*2}{cm a}{cm e*8}{cm s}"
3680 PRINT"{space*2}{sh -}decoder1{sh -}"
3685 PRINT"{space*2}{cm z}{sh asterisk*4}{cm r}{sh asterisk*3}{cm x}"
3690 PRINT"{space*2}{cm a}{sh asterisk*4}{cm e}{sh asterisk*3}{cm s}"
3695 PRINT"{space*2}{sh -}memory 1{sh -}"
3700 PRINT"{space*2}{cm z}{cm r*8}{cm x}"
3705 PRINT" {sh asterisk*2}Q{sh +*7}{sh asterisk*3}"
3710 PRINT" {sh asterisk*3}Q{sh +*6}{sh asterisk*3}"
3715 PRINT" {sh asterisk*4}Q{sh +*5}{sh asterisk*3}"
3720 PRINT" {sh asterisk*5}Q{sh +*4}{sh asterisk*3}{reverse on}data"
3725 PRINT" {sh asterisk*6}Q{sh +*3}{sh asterisk*3}{reverse on}bus "
3730 PRINT" {sh asterisk*7}Q{sh +*2}{sh asterisk*3}"
3735 PRINT" {sh asterisk*8}Q{sh +}{sh asterisk*3}"
3740 PRINT" {sh asterisk*9}Q{sh asterisk*3}"
3745 RETURN
3760 RETURN
4000 GOSUB63100:REM micros-4
4001 sn$="04{0*3}":t$="poke 1234,5":GOSUB63000
4015 PRINT"{down}1:{reverse on}6510{reverse off} puts {reverse on}1234{reverse off} on"
4020 PRINT"{down}{space*2}{reverse on}address bus{reverse off}."
4025 PRINT"{down}2:{reverse on}6510{reverse off} puts {reverse on}5{reverse off} on"
4030 PRINT"{down}{space*3}{reverse on}data bus{reverse off}."
4035 PRINT"{down}3:{reverse on}6510{reverse off} sets r/w=0"
4040 PRINT"{down}{space*3}(meaning {reverse on}write{reverse off})."
4045 PRINT"{down}4:{reverse on}memory{reverse off} takes byte"
4050 PRINT"{down}{space*3}off {reverse on}data bus{reverse off}.":GOSUB50000:ms$="{space*2}{reverse on}write{reverse off}":GOSUB63300
4055 t$="x=peek(1234)":GOSUB63000
4060 PRINT"{down}1:{reverse on}6510{reverse off} puts {reverse on}1234{reverse off} on"
4065 PRINT"{down}{space*2}{reverse on}address bus{reverse off}."
4070 PRINT"{down}2:{reverse on}6510{reverse off} sets r/w=1"
4075 PRINT"{down}{space*3}(meaning {reverse on}read{reverse off})."
4080 PRINT"{down}3:{reverse on}memory{reverse off} puts byte"
4085 PRINT"{down}{space*3}on {reverse on}data bus{reverse off}."
4090 PRINT"{down}4:{reverse on}6510{reverse off} takes byte"
4095 PRINT"{down}{space*3}off {reverse on}data bus{reverse off}.":GOSUB50000:ms$="{space*3}{reverse on}read{reverse off}":GOSUB63300
4100 PRINT"{clear}{down*4}Qnote that for 2k"
4105 PRINT"{down} memory chips, only"
4110 PRINT"{down} the top 5 bits on"
4115 PRINT"{down} the {reverse on}address bus"
4120 PRINT"{down} go to the {reverse on}decoder{reverse off}."
4125 PRINT"{down} where do the remaining"
4130 PRINT"{down} 11 bits go ?":GOSUB50000
4135 PRINT"{clear}{down}Qsince 11 bits have"
4140 PRINT"{down} 2^11=2048=2k"
4145 PRINT"{down} possible 1/0"
4150 PRINT"{down} states, these 11"
4155 PRINT"{down} bits are precisely"
4160 PRINT"{down} the number required"
4165 PRINT"{down} to identify one of"
4170 PRINT"{down} the 2048 internal"
4175 PRINT"{down} memory locations"
4180 PRINT"{down} in the chip itself!":GOSUB50000:ms$="how nice!":GOSUB63300
4185 PRINT"{clear}{down*8}Qso{.*4}these 11"
4190 PRINT"{down} bits go directly to"
4195 PRINT"{down} the 2k memory chip.":GOSUB50000:GOSUB4470:GOSUB50000
4200 PRINT"{clear}{down*4}Qhow long does the"
4205 PRINT"{down} {reverse on}6510{reverse off} keep the "
4210 PRINT"{down} address (or data)"
4215 PRINT"{down} on the busses?":GOSUB50000
4220 PRINT"{clear}{down*4}Qwhile the {reverse on}6510{reverse off}"
4225 PRINT"{down} is changing from"
4230 PRINT"{down} one address to"
4235 PRINT"{down} another, what is"
4240 PRINT"{down} to prevent some"
4245 PRINT"{down} decoder from "
4250 PRINT"{down} responding to"
4255 PRINT"{down} an extraneous"
4260 PRINT"{down} intermediate address?":GOSUB50000
4265 PRINT"{clear}{down}Qfortunately the {reverse on}6510"
4270 PRINT"{down} provides a"
4275 PRINT"{down} {reverse on}ready-set-go"
4280 PRINT"{down} signal from one"
4285 PRINT"{down} of it's 40 pins."
4290 PRINT"{down} it's called the
4295 PRINT"{down} {reverse on}phase 2 clock{reverse off}."
4300 PRINT"{down}Qonly when the clock"
4305 PRINT"{down} signal={reverse on}1{reverse off} will"
4310 PRINT"{down} the busses have"
4315 PRINT"{down} valid data.":GOSUB50000
4320 PRINT"{clear}{down*4}Qhence the {reverse on}decoder"
4325 PRINT"{down} must not generate a"
4330 PRINT"{down} {reverse on}chip select{reverse off}, even"
4335 PRINT"{down} if the address is ok,"
4340 PRINT"{down} until the clock='1'."
4345 ms$="tick {reverse on}tock{reverse off}":GOSUB63200:GOSUB50000
4350 PRINT"{clear}{down} {sh asterisk*6}Q{sh asterisk}"
4355 PRINT" {sh asterisk*5}Q{sh +}{sh asterisk}"
4360 PRINT" {sh asterisk*4}Q{sh +*2}{sh asterisk}"
4365 PRINT" {sh asterisk*3}Q{sh +*3}{sh asterisk}"
4370 PRINT" {sh asterisk*2}Q{sh +*4}{sh asterisk}"
4375 PRINT"{space*3}{sh -*5}{space*4}{cm a}{sh asterisk*2}{cm s}"
4380 PRINT"{space*3}{sh -*4}{cm z}{sh asterisk*4}{cm w}{space*2}{sh -}"
4385 PRINT"{space*3}{sh -*3}{cm z}{sh asterisk*5}{cm w}{space*2}{sh -}"
4390 PRINT"{space*3}{sh -*2}{cm z}{sh asterisk*6}{cm w}{reverse on}or{reverse off}{cm q}{sh asterisk}chip"
4395 PRINT"{space*3}{sh -}{cm z}{sh asterisk*7}{cm w}{space*2}{sh -} select"
4400 PRINT"{space*3}{cm z}{sh asterisk*8}{cm w}{space*2}{sh -}"
4410 PRINT"{space*7}{cm a}{sh asterisk*3}{cm s}{sh -}{space*2}{sh -}"
4415 PRINT" clock{sh asterisk}{cm w}{reverse on}not{reverse off}{cm q}{cm w}{space*2}{sh -}"
4420 PRINT"{space*7}{cm z}{sh asterisk*3}{cm x}{cm z}{sh asterisk*2}{cm x}"
4425 PRINT"{down}Qthis takes care of it!"
4430 PRINT"{down} chip select=0 only if"
4435 PRINT"{down} top 5={reverse on}0{reverse off} and{down}{left*3}{cm u*3}{up} clock={reverse on}1":GOSUB50000
4440 PRINT"{clear}{down*4}Qand the phase 2"
4445 PRINT"{down} clock oscillates"
4450 PRINT"{down} between '0' and '1'"
4455 PRINT"{down} at a rate of"
4460 PRINT"{down}{right}1 megahertz!":PRINT"{down} (1 million times each second).":GOSUB50000
4465 GOTO5000
4470 PRINT"{clear}{down} {sh asterisk*2}Q{sh asterisk*11}"
4475 PRINT" {sh asterisk*2}{sh +}Q{sh asterisk*9}"
4480 PRINT" {sh asterisk*2}{sh +*2}Q{sh asterisk*8}{reverse on}address"
4485 PRINT" {sh asterisk*2}{sh +*3}Q{sh asterisk*7}{reverse on}bus{space*4}"
4490 PRINT" {sh asterisk*2}{sh +*4}Q{sh asterisk*6}"
4495 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*5}Q{sh asterisk*3}"
4500 PRINT" ..{sh -*5}{.*5}{sh -}{.*3}"
4505 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*5}{sh +*2}{sh asterisk}Q"
4510 PRINT"{space*2}{cm a}{cm e*5}{sh asterisk*3}{cm s} {sh -*2}.{sh -}"
4515 PRINT"{space*2}{sh -}decoder1{sh -} {sh -*2}.{sh -}"
4520 PRINT"{space*2}{cm z}{sh asterisk*4}{cm r}{sh asterisk*3}{cm x} {sh -*2}.{sh -}{arrow left}11"
4525 PRINT" r/w{sh asterisk}{cm s} {sh -}{space*5}{sh -*2}.{sh -}wires"
4530 PRINT"{space*2}{cm a}{sh asterisk*2}{cm e}{sh asterisk}{cm e}{sh asterisk*3}{cm s} {sh -*2}.{sh -}"
4535 PRINT"{space*2}{sh -}memory 1{cm q}{arrow left}{cm x*2}-{cm x}"
4540 PRINT"{space*2}{cm z}{cm r*8}{cm x}"
4545 PRINT" {sh asterisk*2}Q{sh +*7}{sh asterisk*3}"
4550 PRINT" {sh asterisk*3}Q{sh +*6}{sh asterisk*3}"
4555 PRINT" {sh asterisk*4}Q{sh +*5}{sh asterisk*3}"
4560 PRINT" {sh asterisk*5}Q{sh +*4}{sh asterisk*3}{reverse on}data"
4565 PRINT" {sh asterisk*6}Q{sh +*3}{sh asterisk*3}{reverse on}bus "
4570 PRINT" {sh asterisk*7}Q{sh +*2}{sh asterisk*3}"
4575 PRINT" {sh asterisk*8}Q{sh +}{sh asterisk*3}"
4580 PRINT" {sh asterisk*9}Q{sh asterisk*3}{home}"
4585 RETURN
4600 RETURN
5000 GOSUB63100:REM micros-5
5001 sn$="05{0*3}":t$="more memory!":GOSUB63000
5010 PRINT"{down*3}Qif a {reverse on}2k{reverse off} memory chip"
5015 PRINT"{down} takes 11 wires from"
5020 PRINT"{down} the {reverse on}address bus"
5025 PRINT"{down} what about a {reverse on}4k{reverse off}"
5030 PRINT"{down} chip?":GOSUB50000
5035 PRINT"{clear}{down}Qit would take "
5040 PRINT"{down} 12 wires to"
5041 PRINT"{down} identify one of"
5045 PRINT"{down} 2^12=4096=4k"
5046 PRINT"{down} internal locations"
5050 PRINT"{down} in a 4k memory chip."
5055 PRINT"{down} and the remaining"
5060 PRINT"{down} 4 wires would "
5065 PRINT"{down} go to{.*3}?":GOSUB50000
5070 PRINT"{clear}{down*5}{space*2}the {reverse on}decoder{reverse off}!":GOSUB50000:ms$="where else":GOSUB63300
5075 PRINT"{clear}{down}Qwe're talking about"
5080 PRINT"{down} static memory called"
5085 PRINT"{down} {reverse on}r{reverse off}andom {reverse on}a{reverse off}ccess"
5090 PRINT"{down} {reverse on}m{reverse off}emory (ram)."
5095 PRINT"{down}Qthe {reverse on}6510{reverse off} can"
5100 PRINT"{down} {reverse on}read{reverse off} or {reverse on}write{reverse off}"
5105 PRINT"{down} with {reverse on}ram{reverse off}{.*3}and"
5110 PRINT"{down} {reverse on}ram{reverse off} will store"
5115 PRINT"{down} data bytes as"
5120 PRINT"{down} long as it has"
5125 PRINT"{down} power.":GOSUB50000
5130 PRINT"{clear}{down*3}Qprograms in {reverse on}basic{reverse off} are"
5135 PRINT"{down} normally stored in"
5140 PRINT"{down} {reverse on}ram{reverse off}{.*3}and they are"
5145 PRINT"{down} lost when the computer"
5150 PRINT"{down} is turned off!":GOSUB50000
5155 PRINT"{clear}{down}Qhowever {reverse on}r{reverse off}ead {reverse on}o{reverse off}nly"
5160 PRINT"{down} {reverse on}m{reverse off}emory (rom)"
5165 PRINT"{down} never forgets!"
5170 PRINT"{down} the data is permanent."
5175 PRINT"{down} the {reverse on}6510{reverse off} cannot"
5180 PRINT"{down} {reverse on}write{reverse off} to {reverse on}rom{reverse off}."
5185 PRINT"{down}Qit can only {reverse on}read{reverse off} {reverse on}rom{reverse off}."
5190 GOSUB50000
5195 PRINT"{clear}{down}Qthe decoding is the"
5200 PRINT"{down} same as for {reverse on}ram{reverse off}"
5205 PRINT"{down} but the {reverse on}read/write"
5210 PRINT"{down} line is not used."
5215 PRINT"{down}Qwhen the appropriate"
5220 PRINT"{down} address is on the"
5225 PRINT"{down} {reverse on}address bus{reverse off}, and"
5226 PRINT"{down} the {reverse on}decoder{reverse off} sends a"
5227 PRINT"{down} {reverse on}chip enable{reverse off}{.*4}"
5230 PRINT"{down} rom always{down}{left*6}{cm u*6}{up} puts"
5235 PRINT"{down} data on the {reverse on}data bus{reverse off}."
5240 GOSUB50000
5245 PRINT"{clear}{down}Qit is {reverse on}rom{reverse off} which"
5250 PRINT"{down} contains the info"
5255 PRINT"{down} necessary for the"
5260 PRINT"{down} {reverse on}6510{reverse off} to understand"
5265 PRINT"{down} the {reverse on}basic{reverse off} language."
5270 PRINT"{down}Qit is {reverse on}rom{reverse off} which"
5275 PRINT"{down} contains the"
5280 PRINT"{down} programs which"
5285 PRINT"{down} make the micro"
5290 PRINT"{down} smart{down}{left*5}{cm u*5}{up} as soon"
5295 PRINT"{down} as it's turned on!":ms$="sin({pi}/2)=1":GOSUB63200:GOSUB50000
5475 PRINT"{clear}{down*2}Qnow consider the commodore 64:"
5476 PRINT"{down} it has 64k of {reverse on}ram{reverse off}{.*3}":GOSUB50000     :
5477 PRINT"{down} right?":GOSUB50000:ms$=" right!!":GOSUB63200:GOSUB50000
5478 PRINT"{home}{down*6}Qbut it's smart and has"
5479 PRINT"{down} lot's of {reverse on}rom{reverse off}{.*3}":GOSUB50000:PRINT"{down} right?":GOSUB50000:GOSUB63200
5480 PRINT"{home}{down*10}Qbut the {reverse on}6510{reverse off} has only a"
5481 PRINT"{down} 16 bit address bus?!?":GOSUB50000:ms$=" {reverse on}!#$%'{?*3}{reverse off}":GOSUB63200
5482 GOSUB50000:PRINT"{clear}{down*5}Qso how does the {reverse on}6510{reverse off} talk to"
5483 PRINT"{down} 64k of {reverse on}ram{reverse off} and{down}{left*3}{cm y*3}{up} 20k of {reverse on}rom{reverse off}":ms$="{?*10}":GOSUB50000
5484 PRINT"{down}Qbesides..how come it says:":PRINT"{down} {reverse on}only{reverse off} 38911 bytes free{?*3}"
5485 ms$="i{reverse on}wuz{reverse off}robbed":GOSUB63200
5486 GOSUB50000:PRINT"{clear}{down*4}Qnow that's{down}{left*6}{cm u*6}{up} another story!"
5487 ms$="au revoir!":GOSUB63200:sn$="{0*3}10":GOSUB63520:END
5490 PRINT"{clear}{down} {sh asterisk*2}Q{sh asterisk*11}"
5491 PRINT" {sh asterisk*2}{sh +}Q{sh asterisk*9}"
5495 PRINT" {sh asterisk*2}{sh +*2}Q{sh asterisk*8}{reverse on}address"
5500 PRINT" {sh asterisk*2}{sh +*3}Q{sh asterisk*7}{reverse on}bus{space*4}"
5505 PRINT" {sh asterisk*2}{sh +*4}Q{sh asterisk*6}"
5510 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*5}Q{sh asterisk*3}"
5515 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*5}{sh +}Q{sh asterisk*2}"
5520 PRINT" ..{sh -*5}{.*5}{sh -*2}.."
5525 PRINT" {sh asterisk*2}{sh +*5}{sh asterisk*5}{sh +*2}{sh asterisk}Q"
5530 PRINT"{space*2}{cm a}{cm e*5}{sh asterisk*3}{cm s} {sh -*2}.{sh -}"
5535 PRINT"{space*2}{sh -}decoder1{sh -} {sh -*2}.{sh -}"
5540 PRINT"{space*2}{cm z}{sh asterisk*4}{cm r}{sh asterisk*3}{cm x} {sh -*2}.{sh -}{arrow left}{reverse on}11"
5545 PRINT" r/w{sh asterisk}{cm s} {sh -}{space*5}{sh -*2}.{sh -}{reverse on}wires"
5550 PRINT"{space*2}{cm a}{sh asterisk*2}{cm e}{sh asterisk}{cm e}{sh asterisk*3}{cm s} {sh -*2}.{sh -}"
5555 PRINT"{space*2}{sh -}memory 1{cm q}{arrow left}{cm x*2}-{cm x}"
5560 PRINT"{space*2}{cm z}{cm r*8}{cm x}"
5565 PRINT" {sh asterisk*2}Q{sh +*7}{sh asterisk*3}"
5570 PRINT" {sh asterisk*3}Q{sh +*6}{sh asterisk*3}"
5575 PRINT" {sh asterisk*4}Q{sh +*5}{sh asterisk*3}"
5580 PRINT" {sh asterisk*5}Q{sh +*4}{sh asterisk*3}{reverse on}data"
5585 PRINT" {sh asterisk*6}Q{sh +*3}{sh asterisk*3}{reverse on}bus "
5590 PRINT" {sh asterisk*7}Q{sh +*2}{sh asterisk*3}"
5595 PRINT" {sh asterisk*8}Q{sh +}{sh asterisk*3}"
5600 PRINT" {sh asterisk*9}Q{sh asterisk*3}"
5605 RETURN
5620 RETURN
50000 GETa$:IFa$<>""THEN50000
50001 GETa$:IFa$=""THEN50001
50002 IFa$="@"THEN63500
50003 RETURN
51000 n=3
51001 x$="":FORu=nTO0STEP-1:x%=x/(2^u):x=x-x%*(2^u):x$=x$+CHR$(48+x%)
51002 NEXT:RETURN
52000 m=3
52001 y$="":FORv=mTO0STEP-1:y%=y/(16^v):y=y-y%*(16^v)
52002 y$=y$+CHR$(48+y%-7*(y%>9)):NEXT:RETURN
55000 PRINT"{clear}{down*4}":POKE59468,14:PRINTCHR$(14)
55005 PRINT" These{space*2}micros'n'chips tutorials are"
55010 PRINT"{down} meant to provide{space*2}an{space*2}understanding"
55020 PRINT"{down} of microcomputer{space*2}hardware.They are"
55030 PRINT"{down} not{space*2}intended{space*2}to{space*2}be{space*3}exhaustive."
55040 PRINT"{down} Although they refer specifically to"
55050 PRINT"{down} the{space*2}commodore 64,{space*2}the{space*2}ideas{space*2}are"
55060 PRINT"{down} applicable to all micros."
55070 GOSUB50000:PRINT"{clear}":POKE59468,12:PRINTCHR$(142):RETURN
63000 PRINT"{clear}";
63001 l=LEN(t$):uu$="":FORi=1TOl:uu$=uu$+" ":NEXT:tt$=uu$+t$
63002 PRINT" {cm a}";:FORi=1TOl:PRINT"{sh asterisk}";:NEXT:PRINT"{cm s}"
63003 PRINT" {sh -}";:FORi=1TOl:PRINT" ";:NEXT:PRINT"{reverse off}{sh -}"
63004 PRINT" {cm z}";:FORi=1TOl:PRINT"{sh asterisk}";:NEXT:PRINT"{cm x}":PRINT"{up*2}{right*2}{reverse on}{red}";
63005 FORi=1TOl:PRINTMID$(tt$,i+1,l):PRINT"{up}{right*2}{reverse on}";:FORt=1TO50:NEXT
63006 NEXT:PRINT"{black}":RETURN
63100 bt$="{home}{down*24}"
63101 pt$="{red}{cm a}{sh asterisk*10}{cm s}{down}{left*12}{sh -}{right*10}{sh -}{down}{left*12}{cm z}{cm r}{sh asterisk*8}{cm r}{cm x}"
63102 pt$=pt$+"{down}{left*13}N{cm t*12}M{down}{left*14}{cm g}{=*12}{cm m}"
63103 pt$=pt$+"{down}{left*14}PO{cm t*10}PO{up*4}{left*12}"
63104 pt$=bt$+"{up*6}{right*26}"+pt$+"{black}"
63105 sn=1030:IFPEEK(0)=47THENsn=2054
63199 RETURN
63200 FORi=1TO2:PRINTpt$"{space*10}"
63201 FORt=1TO50:NEXT
63202 PRINTpt$ms$
63203 FORt=1TO50:NEXT:NEXT:RETURN
63300 GOSUB63200:FORt=1TO1000:NEXT:RETURN
63500 vs=VAL(sn$):vs=vs-1000:IFvs<1000THENvs=100
63510 sn$=MID$(STR$(vs),2):sn$=RIGHT$("{0*5}"+sn$,5):GOSUB63520:RUN
63520 FORi=1TO5:POKEsn+i-1,ASC(MID$(sn$,i,1)):NEXT:RETURN
stop tok64
(bastext 1.0)