IC function:	1 Mbit (1M×1) DRAM
Related components:	8 kbit (8k×1) DRAM, 16 kbit (16k×1) DRAM, 64 kbit (64k×1) DRAM, 256 kbit (256k×1) DRAM

Component documentation

IC number	Manufacturer	Documentation
µPD421000	NEC	Not available
MSM511000	Oki	Not available

Component versions

IC number	Package	Access time	CBM part number	CBM part description
µPD421000C-10, MSM511000-10RS	18-pin DIP	100 ns	318076-01	IC, DRAM 1MB X 1

Positions

Device	Installed RAM	Positions	Positions (not installed)	Package	Access time
A2058	8 Mb	U15..U78		DIP	100 ns
	4 Mb	U15..U30, U47..U62	U31..U46, U63..U78
	2 Mb	U15, U17, U19, U21, U23, U25, U27, U29, U47..U54	U16, U18, U20, U22, U24, U26, U28, U30..U46, U55..U78

Pinout

Pin	Type	Name
1	Input	DIN
2	Input	_WE
3	Input	_RAS
4	N/C	NC
5..8	Input	Address
9	Power	VCC
10..15	Input	Address
16	Input	_CAS
17	Output	DOUT
18	Power	GND