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TI-99/4A Side port - Side cart

44 pin connector

WARNING! Any hardware misconfiguration or improper power-pull from the side port can damage/destroy the TI-99!

Pin

Name

Direction

Description _

1 VCC (+5V) - +5 Volts power supply

2 SBE OUT Low if addr in >9000-94xx (sound port)

3 RESET* OUT System reset (active low)

4 EXTINT* IN External interrupt (active low)

5 A5 OUT Address bus, bit 5

6 A10 OUT -

7 A4 OUT -

8 A11 OUT -

9 DBIN (DIN) OUT Active high = read memory

10 A3 OUT -

11 A12 OUT -

12 READY IN Active high = memory is ready

13 LOAD* IN Unmaskable interrupt (=> BLWP @>FFFC)

14 A8 OUT -

15 A13 OUT -

16 A14 OUT -

17 A7 OUT -

18 A9 OUT -

19 A15/CRUOUT OUT Address bus, lsb. Also CRU output bit.

20 A2 OUT -

21 GND - Ground

22 CRUCLK* OUT Inversion of TMS9900 CRUCLOCK pin

23 GND - Ground

24 PHI3* OUT Inversion of phase 3 clock

25 GND - Ground

26 WE* OUT Write Enable (derived from TMS9900 WE* pin)

27 GND - Ground

28 MBE* OUT Active low if addr in >4000-5FFF (card ROMs)

29 A6 OUT -

30 A1 OUT -

31 A0 MSB OUT Address bus, bit 0 (most significant bit)

32 MEMEN* (ME) OUT Memory access enable (active low)

33 CRUIN IN CRU input bit to TMS9900

34 D7 IN/OUT Data bus, bit 7 (least significant)

35 D4 IN/OUT -

36 D6 IN/OUT -

37 D0 IN/OUT Data bus, bit 0 (most significant)

38 D5 IN/OUT -

39 D2 IN/OUT -

40 D1 IN/OUT -

41 IAQ IN Interrupt acknowledged by TMS9900

42 D3 IN/OUT -

43 VDD (-5V) - -5 Volts power supply

44 AUDIOIN IN To sound generator AUDIO IN pin

I/O PIN Description

Signature PIN I/O Description A0 (MSB) 31 Out Address Bus 16-bit memory when MEMEN is active A1 30 Out Address Bus 16-bit memory when MEMEN is active A2 20 Out Address Bus 16-bit memory when MEMEN is active A3 10 Out Address Bus 16-bit memory when MEMEN is active A4 7 Out Address Bus 16-bit memory when MEMEN is active A5 5 Out Address Bus 16-bit memory when MEMEN is active A6 29 Out Address Bus 16-bit memory when MEMEN is active A7 17 Out Address Bus 16-bit memory when MEMEN is active A8 14 Out Address Bus 16-bit memory when MEMEN is active A9 18 Out Address Bus 16-bit memory when MEMEN is active A10 6 Out Address Bus 16-bit memory when MEMEN is active A11 8 Out Address Bus 16-bit memory when MEMEN is active A12 11 Out Address Bus 16-bit memory when MEMEN is active A13 15 Out Address Bus 16-bit memory when MEMEN is active A14 16 Out Address Bus 16-bit memory when MEMEN is active A15/CRUOUT 19 Out Address Bus 16-bit memory when MEMEN is active A15 is also used for CRU Data out on CRU output inst. D0 (MSB) 37 I/O bidirectional data bus D1 40 I/O bidirectional data bus D2 39 I/O bidirectional data bus D3 42 I/O bidirectional data bus D4 35 I/O bidirectional data bus D5 38 I/O bidirectional data bus D6 36 I/O bidirectional data bus D7 34 I/O bidirectional data bus

Pin	Name	Direction	Description _
1	VCC (+5V)	-	+5 Volts power supply
2	SBE	OUT	Low if addr in >9000-94xx (sound port)
3	RESET*	OUT	System reset (active low)
4	EXTINT*	IN	External interrupt (active low)
5	A5	OUT	Address bus, bit 5
6	A10	OUT	-
7	A4	OUT	-
8	A11	OUT	-
9	DBIN (DIN)	OUT	Active high = read memory
10	A3	OUT	-
11	A12	OUT	-
12	READY	IN	Active high = memory is ready
13	LOAD*	IN	Unmaskable interrupt (=> BLWP @>FFFC)
14	A8	OUT	-
15	A13	OUT	-
16	A14	OUT	-
17	A7	OUT	-
18	A9	OUT	-
19	A15/CRUOUT	OUT	Address bus, lsb. Also CRU output bit.
20	A2	OUT	-
21	GND	-	Ground
22	CRUCLK*	OUT	Inversion of TMS9900 CRUCLOCK pin
23	GND	-	Ground
24	PHI3*	OUT	Inversion of phase 3 clock
25	GND	-	Ground
26	WE*	OUT	Write Enable (derived from TMS9900 WE* pin)
27	GND	-	Ground
28	MBE*	OUT	Active low if addr in >4000-5FFF (card ROMs)
29	A6	OUT	-
30	A1	OUT	-
31	A0 MSB	OUT	Address bus, bit 0 (most significant bit)
32	MEMEN* (ME)	OUT	Memory access enable (active low)
33	CRUIN	IN	CRU input bit to TMS9900
34	D7	IN/OUT	Data bus, bit 7 (least significant)
35	D4	IN/OUT	-
36	D6	IN/OUT	-
37	D0	IN/OUT	Data bus, bit 0 (most significant)
38	D5	IN/OUT	-
39	D2	IN/OUT	-
40	D1	IN/OUT	-
41	IAQ	IN	Interrupt acknowledged by TMS9900
42	D3	IN/OUT	-
43	VDD (-5V)	-	-5 Volts power supply
44	AUDIOIN	IN	To sound generator AUDIO IN pin