74LS169 synchronous 4-bit up/down counter pinout

DIP-16. Presettable synchronous binary counter, up or down; often a programmable clock divider

On the Electron (IC9) it divides the 16 MHz clock by 13 for the cassette and baud timing: CLK (pin 2) takes 16 MHz from the 74S04 pin 8, A and B (pins 3, 4) are tied high and C and D (5, 6) low, and QD (pin 11) gives an 812 ns (1.23 MHz) clock to ULA pin 55 and expansion pin 13. No output = tape dead. The board also takes a 74LS163 with the extra parts R59, R60, R62, Q9 marked * on the drawing.

Open the interactive 74LS169 pinout

Pins

Pin	Name	Type	Signal
1	U/D	ctrl	Count direction: high = up, low = down.
2	CLK	clock	Clock; counts on the rising edge.
3	A	ctrl	Preset data A (least significant).
4	B	ctrl	Preset data B.
5	C	ctrl	Preset data C.
6	D	ctrl	Preset data D (most significant).
7	/ENP	ctrl	Count enable P (both enables low to count).
8	GND	ground	Ground.
9	/LOAD	ctrl	Synchronous load of A-D on the next clock.
10	/ENT	ctrl	Count enable T; also enables RCO.
11	QD	io	Counter output D (most significant).
12	QC	io	Counter output C.
13	QB	io	Counter output B.
14	QA	io	Counter output A (least significant).
15	/RCO	ctrl	Ripple carry out: low at terminal count (15 up, 0 down).
16	VCC	power	+5 V.

Fitted in

Acorn Electron IC9

74LS169 synchronous 4-bit up/down counter pinout

Pins

Fitted in

Sources