connectors.md

Connectors

X1 - system bus

Pin 1 is bottom left, 2 is top left (as seen from the outside).

Signal	Bottom pin	Top pin	Signal
RESET	1	2	~CS3
~I/OR	3	4	~CS2
~INTA	5	6	~CS1
A13	7	8	-
A11	9	10	+5V
A12	11	12	-
~MEMW	13	14	-
A8	15	16	-
A1	17	18	GND
A0	19	20	-
A9	21	22	-
A2	23	24	-
A7	25	26	-
A15	27	28	-
A14	29	30	-
A3	31	32	-
D3	33	34	-
D2	35	36	-
D4	37	38	-
D1	39	40	-
D5	41	42	-
D0	43	44	-
D6	45	46	-
D7	47	48	-
A10	49	50	HLDA
~MEMR	51	52	A4
~I/OW	53	54	A5
INTE	55	56	A6
INT	57	58	~RESIN
HOLD	59	60	φ2TTL

X2 - PIO

Pin 1 is bottom left, 2 is top left (as seen from the outside).

Signal	Bottom pin	Top pin	Signal
PB2	1	2	-
PB1	3	4	-
PB0	5	6	~PC2
PB3	7	8	~PC3
PB4	9	10	-
PB5	11	12	-
PB6	13	14	-
PB7	15	16	-
-	17	18	-
PC5	19	20	-
PC6	21	22	-
PC7	23	24	-
PA7	25	26	-
PA6	27	28	-
PA5	29	30	-
PA4	31	32	-
PA3	33	34	-
PA2	35	36	-
PA1	37	38	-
PA0	39	40	GND

X3 - tape recorder

Pin	Signal
1	Output (to tape)
2	GND
3	Input (from tape)

X4 - power supply

Pin	Signal
1	+12V
2	+5V
3	GND
4	-5V
5	GND

X5 - video output

Pin	Signal
1	-
2	VIDEO (CVBS mono)
3	B
4	G
5	R
6	GND

Keyboard

Keyboard is connected using wires soldered to numbered pads. Unfortunately, numbers do not match.

Signal	Mainboard pad	Keyboard PCB pad
D0	8	34
D1	7	33
D2	6	32
D3	5	31
D4	4	30
D5	3	29
D6	2	28
D7	1	27
A0	11	9
A1	12	8
~I/OR	14	5
~I/OW	15	36
RESET	13	35
~CS1	9	6
~RESIN	10	10
BUZZER	16	16