9316B / 2316B ROM 2K x 8 pinout

DIP-24. 2K x 8 mask ROM: Apple II monitor and BASIC ROMs; TRS-80 ROM C and character generator

24-pin 2 KB mask ROM with three chip selects (pins 18, 20, 21) whose polarity is set by the mask, so it depends on the part. Board wiring, by machine: Apple II and II Plus: six sockets cover $D000-$FFFF (drawn as 9316B); /CS1 (20) and /CS3 (21) are active LOW, tied together and driven by the 74LS138 at F12, one output per 2 KB block; CS2 (18) is active HIGH and follows the slot /INH line, so a card pulling /INH LOW turns every ROM off. TRS-80 Model III: ROM C (U106) has pin 18 grounded, pin 21 tied to +5 V and pin 20 driven by /ROMC (Technical Reference Fig. 6, p. 33). A 2716 EPROM has /CE, /OE and Vpp on pins 18, 20 and 21 with other polarities, so it needs an adapter or rewiring.

Open the interactive 9316B pinout

Pins

Pin	Name	Type	Signal
1	A7	addr	Address bus bit 7.
2	A6	addr	Address bus bit 6.
3	A5	addr	Address bus bit 5.
4	A4	addr	Address bus bit 4.
5	A3	addr	Address bus bit 3.
6	A2	addr	Address bus bit 2.
7	A1	addr	Address bus bit 1.
8	A0	addr	Address bus bit 0.
9	D0	data	Data bit 0 out.
10	D1	data	Data bit 1 out.
11	D2	data	Data bit 2 out.
12	GND	ground	0 V.
13	D3	data	Data bit 3 out.
14	D4	data	Data bit 4 out.
15	D5	data	Data bit 5 out.
16	D6	data	Data bit 6 out.
17	D7	data	Data bit 7 out.
18	CS2	ctrl	Chip select; polarity set by the mask (board wiring in the summary).
19	A10	addr	Address bus bit 10.
20	CS1	ctrl	Chip select; polarity set by the mask (board wiring in the summary). (2716: /OE.)
21	CS3	ctrl	Chip select; polarity set by the mask (board wiring in the summary).
22	A9	addr	Address bus bit 9.
23	A8	addr	Address bus bit 8.
24	+5V	power	+5 V.

Fitted in

Apple II
Apple II Plus
TRS-80 Model III U106 (ROM C) and U36 (character generator MCM68A316E)
TRS-80 Model 4 U70 (MCM68A316 ROM C) and U23 (MCM68A316E character generator)

9316B / 2316B ROM 2K x 8 pinout

Pins

Fitted in

Sources