4 Mbit EPROM used in Commodore and Amiga equipment

IC function: 4 Mbit (128k×16 / 256k×8) EPROM
Related components: 4 Mbit Mask ROM (pin compatible Mask ROM), 2 Mbit Mask ROM (used in newer A570)

Component documentation
IC number	Manufacturer	Documentation
27C400	Intel	Not available
µPD27C4000	NEC	Not available

Component versions
IC number	Package
D27C400	40-pin Ceramic DIP
µPD27C4000D	40-pin Ceramic DIP

Programmed components
CBM part number	CBM part description	Part description
391298-01		A570 / A690 ROM V1.0

Positions
Amiga	Position	Package
A570 / A690	U20	DIP

Pinout
Socket pin	ROM pin	Type	Name	Signal name
Socket pin	ROM pin	Type	Name	A570 / A690
1			(A18)	A19
2	1	Input	A17	A18
3..10	2..9	Input	A7..A0	A8..A1
11	10	Input	_CS	connected to SW1 and R29
12	11	Power	GND	GND
13	12	Input	_OE	*CSROM
14	13	Output	D0	D0
15	14	Output	D8	D8
16	15	Output	D1	D1
17	16	Output	D9	D9
18	17	Output	D2	D2
19	18	Output	D10	D10
20	19	Output	D3	D3
21	20	Output	D11	D11
22	21	Power	VCC	VCC
23	22	Output	D4	D4
24	23	Output	D12	D12
25	24	Output	D5	D5
26	25	Output	D13	D13
27	26	Output	D6	D6
28	27	Output	D14	D14
29	28	Output	D7	D7
30	29	Output	D15	D15
31	30	Power	VSS	GND
32	31	Input	_BYTE	VCC
33..41	32..40	Input	A16..A8	A17..A9
42			(NC)	unused