MC6801 microcontroller pinout

DIP-40. ADAMnet processors (single-chip mode, 1 MHz). Master and tape-drive 6801s on the Memory and I/O board; keyboard and printer each have their own.

The ADAM runs every ADAMnet device on a 6801 in single-chip mode, clocked from a 4 MHz crystal divided by four (1 MHz E). The master 6801 talks to the Z80 through the MIOC and runs the network; a second 6801 on the same board runs the data drive; the keyboard and printer carry their own. A dead master 6801 means no tape, keyboard or printer. The printer also holds the power supply, so check its rails first. No replacement part exists: each 6801 runs Coleco's program from its own 2 KB mask ROM, so a blank MC6801 or a ROM-less MC6803 will not work. Only a 6801 from the same position on a donor board (master, data drive, keyboard or printer) will run.

Open the interactive 6801 pinout

Pins

Pin	Name	Type	Signal
1	Vss	ground	Ground.
2	XTAL1	clock	Crystal input 1 for the on-chip oscillator. The ADAM uses a 4 MHz crystal.
3	EXTAL2	clock	Crystal input 2, or the external clock input when no crystal is used.
4	/NMI	ctrl	Non-maskable interrupt input. Active LOW.
5	/IRQ1	ctrl	Maskable interrupt input 1. Active LOW.
6	/RESET	ctrl	Reset. The rising edge also latches the mode from P20-P22. Stuck LOW means no ADAMnet.
7	Vcc	power	+5 V supply.
8	P20	io	Port 2 bit 0. Mode bit PC0 at reset; timer input capture (TIN).
9	P21	io	Port 2 bit 1. Mode bit PC1 at reset; timer output compare (TOUT).
10	P22	io	Port 2 bit 2. Mode bit PC2 at reset; serial clock (SCLK).
11	P23	io	Port 2 bit 3. Serial receive (SCI RX) when the UART is on.
12	P24	io	Port 2 bit 4. Serial transmit (SCI TX) when the UART is on.
13	P10	io	Port 1 bit 0. General I/O.
14	P11	io	Port 1 bit 1. General I/O.
15	P12	io	Port 1 bit 2. General I/O.
16	P13	io	Port 1 bit 3. General I/O.
17	P14	io	Port 1 bit 4. General I/O.
18	P15	io	Port 1 bit 5. General I/O.
19	P16	io	Port 1 bit 6. General I/O.
20	P17	io	Port 1 bit 7. General I/O.
21	Vcc Standby	power	Standby supply for the on-chip RAM. Must be powered whenever the internal RAM is used.
22	P47	io	Port 4 bit 7. General I/O in single-chip mode.
23	P46	io	Port 4 bit 6.
24	P45	io	Port 4 bit 5.
25	P44	io	Port 4 bit 4.
26	P43	io	Port 4 bit 3.
27	P42	io	Port 4 bit 2.
28	P41	io	Port 4 bit 1.
29	P40	io	Port 4 bit 0.
30	P37	io	Port 3 bit 7. General I/O in single-chip mode.
31	P36	io	Port 3 bit 6.
32	P35	io	Port 3 bit 5.
33	P34	io	Port 3 bit 4.
34	P33	io	Port 3 bit 3.
35	P32	io	Port 3 bit 2.
36	P31	io	Port 3 bit 1.
37	P30	io	Port 3 bit 0.
38	SC2	ctrl	Strobe/control 2. In single-chip mode: output strobe OS3 for port 3. (R/W in expanded modes.)
39	SC1	ctrl	Strobe/control 1. In single-chip mode: input strobe IS3 for port 3. (IOS or AS in expanded modes.)
40	E	clock	Enable clock output, crystal ÷ 4.

Fitted in

Coleco ADAM

MC6801 microcontroller pinout

Pins

Fitted in

Sources