Adr. Code Befehl Kommentar
(dez.)
00 39 CLR A (URSTART)
01 57 OUTL P1,A Port löschen
02 20 08 CALL BYTE Resetmeldg.
04 20 08 CALL BYTE überlesen
06 04 40 JP HAUPT
08 186 00 MOV R2,0 (UP BYTE)
10 39 CLR A auf Taste
11 54 11 JT0 warten
13 151 CLR C
14 70 17 JNT1 Datenbit
16 167 CPL C einlesen
17 103 RRCA und in
18 42 XCH A,R2 16 bit-Zahl
19 103 RRCA schieben
20 42 XCH A,R2
21 38 21 JNT0 Clk=H ?
23 188 40 MOV R4,40 Timeout
25 38 13 JNT0 nächstes Bit
27 236 25 DJNZ R4 Schleife
29 42 XCH A,R2 12 bit zu
30 247 RLCA 8 bit
31 42 XCH A,R2 umformen
32 247 RLCA
33 170 MOV R2,A Taste in R2
34 131 RET
Adr. Code Befehl Kommentar
(dez.)
40 (HAUPTPROG.)
40 191 00 MOV R7,0 Shift löschen
42 20 08 CALL BYTE Taste lesen
44 03 84 ADD A,84 Shift rechts?
46 150 52 JNZ
48 191 128 MOV R7,128 Shift setzen
50 04 85 JP
52 250 MOV A,R2
53 03 119 ADD A,119 Shift links?
55 198 48 JZ
57 250 MOV A,R2
58 03 08 ADD A,08 Taste losgelassen?
60 198 74 JZ
62 250 MOV A,R2
63 03 208 ADD A,208 Code>48?
65 246 68 JC Code= alter Code-48
67 250 MOV A,R2
68 20 110 CALL MAKRO Makro testen
70 111 ADD A,R7 Shift addieren
71 57 OUTL P1,A Taste ausgeben
72 04 42 JP
74 20 08 CALL BYTE Folgebyte
76 03 84 ADD A,84 Shift re.?
78 198 88 JZ
80 250 MOV A,R2
81 03 119 ADD A,119 Shift li.?
83 198 88 JZ
85 39 CLR A norm. T. losgelassen
86 04 70 JP
88 191 00 MOV R7,0 Shift losgelassen
90 04 85 JP
Adr. Code Befehl Kommentar
(dez.)
95 39 CLR A (WAITROUTINE)
96 98 MOV T,A
97 187 07 MOV R3,7 Ausgabefrequenz
99 85 START T
100 22 104 JTF
102 04 100 JP
104 235 100 DJNZ R3
106 131 RET
110 170 MOV R2,A (MAKROAUSGABE)
111 03 174 ADD A,174 F1?
113 150 121 JNZ
115 184 200 MOV R0, 200 Tabelle
117 185 10 MOV R1, 10 10 Codes
119 04 160 JP OUT
121 250 MOV A,R2
122 03 173 ADD A, 173 F2?
124 150 132 JNZ
126 184 210 MOV R0, 210 Tabelle
128 185 04 MOV R1, 4 4 Codes
130 04 160 JP OUT
132 250 MOV A, R2
133 03 254 ADD A, 254 F3?
135 150 143 JNZ
137 184 215 MOV R0, 215 Tabelle
139 185 03 MOV R1, 3 3 Codes
141 04 160 JP OUT
143 250 MOV A, R2
144 03 170 ADD A, 170 F4?
146 150 172 JNZ
148 184 220 MOV R0, 220 Tabelle
150 185 03 MOV R1, 3 3 Codes
152 04 160 JP OUT
Adr. Code Befehl Kommentar
(dez.)
(UP Out)
160 39 Clr A keine Taste
161 57 Outl P1,A gedrückt (ZX)
162 20 95 Call Wait warten
164 248 Mov A, R0 nächsten
165 163 Mov A, (A) Code aus der
166 57 Outl P1,A Tab. holen
167 20 95 Call Wait warten
169 24 Inc R0 nächste Zelle
170 233 160 DJNZ R1 fertig?
172 250 Mov A, R2 alten Code
173 131 RET herstellen
Makrotabellen:
F1 -> Adr.200: 118/253/117/11/95/95/31/31/112/246
Makro: PRINT/Shift Enter/USR/1/2/2/8/8/,/"
F2 -> Adr.210:22/253/117/31
Makro: RAND/Shift Enter/USR/8
F3 -> Adr.215: 114/31/112
Makro: POKE/8/,
F4 -> Adr.220: 118/253/114
Makro: PRINT/Shift Enter/PEEK
Any AT keyboard can be connected to the ZX81. The interface receives the 12-bit serial data from the keyboard and transforms it into 7-bit-Code plus one bit for Shiftkey. The 2716-EPROM E2 presents the ZX keyboard matrix and matches the ZX leads A8 … A15 with the 8-bit from the 8049 to data DO … D4. Remember, the ZX reads the keyboard by pulling one of A8 … A15 to low and reading the port SFE.
Just before finishing the AT-interface, I heard that a ZX-user from USA (see IKI by Jack Dohany, ZAQ! Spring ’96) developed a similar interface, but using XT-keyboards. Due to the 8049 microcontroller my interface is programmable; you can press one function key (F 1 … F12) at the keyboard and the interface gives a sequence of some keys to the ZX81!
Kai Fischer, [address omitted], Germany [phone number omitted]