IC number:	Z8400 (Z80A CPU, Z80B CPU)
IC function:	8-bit microprocessor

Component documentation

IC number	Manufacturer	Documentation
Z8400 - Z80 CPU	Zilog	Product specification (PDF), CPU user's manual (PDF)
Z8400 - Z80 CPU	STMicroelectronics	Not available

Component versions

IC number	Package	Speed	CBM part number	CBM part description
Z8400A - Z80A CPU	40-pin DIP	4 MHz	906150-01	Z80A CPU
Z8400B - Z80B CPU	40-pin DIP	6 MHz	906150-02	Z80B Microprocessor 6 MHz

Positions

Device	Position	Package	Speed
A2090	U28	DIP	4 MHz
A2090A	U28	DIP	4 MHz
C128 revision 6	U10	DIP	6 MHz
C128 revision 7	U10	DIP	6 MHz
C128D	U10	DIP	6 MHz

Pinout

Pin	Type	Name	Signal name
			A2090, A2090A	C128 revision 6	C128 revision 7	C128D
1..5	Output	A11..A15	KA11..KA15	A11..A15
6	Input	CLK	CLK	Z80_PHI via U60 and Q6		Z80_PHI via U60 and U57
7..8	I/O	D4..D3	DB4..DB3 via U31	ZD4..ZD3
9..10	I/O	D5..D6	DB5..DB6 via U31	ZD5..ZD6
11	Power	+5V	VCC	+5V
12	I/O	D2	DB2 via U31	ZD2
13	I/O	D7	DB7 via U31	ZD7
14..15	I/O	D0..D1	DB0..DB1 via U31	ZD0..ZD1
16	Input	INT_	_INTRQ	IRQ_
17	Input	NMI_	VCC via RN6	+5V via R34		+5V
18	Output	HALT_	unused
19	Output	MREQ_	_MRQ	unused
20	Output	IORQ	_IORQ	Z80I/O
21	Output	RD_	_RD	connected to pin 1 of U12
22	Output	WR_	_WR	connected to pin 1 of U31		connected to pin 5 of U31
23	Output	BUSACK_	unused	connected to pin 11 of U37	BUSACK_ via U37
24	Input	WAIT_	_CWAIT	+5V
25	Input	BUSREQ_	VCC via R6	BUSREQ_	connected to pins 6 and 8 of U37 and pin 2 of U60	connected to pins 2 and 4 of U37 and pin 12 of U57
26	Input	RESET_	_XRST	RESET_
27	Output	M1_	unused	M1_
28	Output	RFSH_	_RFSH via U37 and U29	unused
29	Power	GND	GND
30..40	Output	A0..A10	KA0..KA10	A0..A10