Sinclair ZX80 / ZX81 / Z88 Forums

Posted: **Thu Sep 19, 2024 9:26 am**

Hi,

My new project is to read a bar code from the IRQ $7F.

Can be use to select an ID game in a ROM cartrige using a paper or a cardboard picture/info card.
It runs with two bits, and others can drive a joystick.

It's a weird project, but the concept is just funny...

Wait the $7F Bit 7 signal (synchro), and read the secound data on the next raw on the card.

Test card 40x50mm:

: Test_Card.jpg (28.24 KiB) Viewed 1687 times

ZX81_CardReader.pdf: (169.21 KiB) Downloaded 120 times

Work in progress...

Posted: **Sat Sep 21, 2024 2:13 pm**

Hi,

The first release is ready (Kicad r.8):
http://zx81.ordi5.free.fr/brico/ZX81_CardReader/

Driver:

Code: Select all

;------- TASM ASM mnemonics. -------
; Compile this file using:
; Set TASMOPTS = -b
; tasm -80 ThisCode.tas MyBinary.BIN
;-----------------------------------
; Zx81 Program name: VB81 XuR [CardReader.bas] :
; REM   line   name: D=16514/16693 : H=4082/4135

#define ORG  .org       ; TASM cross-assembler definitions
#define equ  .equ
;-----------------------------------

;------------------------------------
;-BASIC sub-routine entry.          -
;+----------------------------------+
; Lb4082  ;  <- USR BASIC Enty.
;+----------------------------------+


ORG $4082 ; [@16514/@h4082]
; OPTICAL READER  (BITs 6-7)
; 7 =SYNC
; 6 =DATA (BLACK STRIP=1 WHITE=0)

Lb4082:
	LD BC,$0800 
Lb4085:
	IN A,($7F) ; MAGECO 8 IO card.
	BIT 7,A 
	JR NZ, Lb4085 ; [$4085:16517]
	LD DE,$0010 ; DELAY / to grab a good  inline data.
Lb408E:
	DEC DE 
	LD A,D 
	OR E 
	JR NZ, Lb408E ; [$408E:16526]
	IN A,($7F) ; MAGECO 8 IO card.
	RR C 
	BIT 6,A 
	JR NZ, Lb409D ; [$409D:16541]
	SET 7,C 
Lb409D:
	DEC B 
	JR Z, Lb40A8 ; [$40A8:16552]
Lb40A0:
	IN A,($7F) ; MAGECO 8 IO card.
	BIT 7,A 
	JR NZ, Lb4085 ; [$4085:16517]
	JR Lb40A0 ; [$40A0:16544]
Lb40A8:
	RET ; ==========================
	
; JOYSTICK (BITs 0-5)
Lb40A9: ; <16553>
	LD BC,$0000 
	IN A,($7F) ; MAGECO LIGHT-PEN [V]/8 IO card.
	RES 6,A 
	RES 7,A 
	LD C,A 
	RET ; ==========================
.end

Code: Select all

     1  REM [HEX:\
01,00,08,DB,7F,CB,7F,20,\
FA,11,00,01,1B,7A,B3,20,\
FB,DB,7F,CB,19,CB,77,20,\
02,CB,F9,05,28,08,DB,7F,\
CB,7F,20,DF,18,F8,C9,01,\
00,00,DB,7F,CB,B7,CB,BF,\
4F,C9 ]

    10 PRINT USR 16514
    15 STOP
    20 PRINT ""JOY:";USR 16553
    30 GOTO 20

CARDREADER.P: (1.09 KiB) Downloaded 87 times

Have fun.

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