Motorola MC6809 connection guide

Motorola MC6809 MC6809 DIP-40 wiring guide with power, signal assignments, and bench checks.

MC6809 DIP-40

40 contacts Current package

Motorola · Motorola P plastic (Case 711), S CERDIP (Case 734) and L ceramic (Case 715) share this top-view 40-pin assignment. On-chip oscillator.

5 V supply and bypass

Required

Apply regulated 5 V and fit a 100 nF ceramic bypass with short connections to the supply rails.

+5 V
- 5 V supply +
- VCC (7)
- C1.1
0 V
- 5 V supply −
- VSS (1)
- C1.2

Bench checks

Verify pin 1 is grounded and measure 4.75–5.25 V at pin 7.
Keep RESET asserted during supply and clock startup. The bypass capacitor is a board-level design choice.

Motorola MC6809 datasheet DS9845-R2, pp. 1–2

Connection scenarios

Driven clock and reset

Use a 4 MHz TTL-compatible logic source on EXTAL, tie XTAL to VSS and bring out E and Q for measurement. Use a separately controlled reset driver with a high above 4.0 V.

Reference
- VSS (1)
- XTAL (39)
- Clock driver GND
- Reset driver GND
- Oscilloscope GND
4 MHz time base
- Clock driver OUT
- EXTAL (38)
Reset
- Reset driver OUT
- /RESET (37)
Run and interrupt idle
E clock probe
- E (34)
- Oscilloscope CH1
Q clock probe
- Q (35)
- Oscilloscope CH2

Bench checks

Confirm that E and Q are 1 MHz and Q leads E. The driver connects to EXTAL only.
Hold RESET low for more than one bus cycle and through supply and clock stabilization. Verify the boot ROM maps 0xFFFE–0xFFFF.
Keep MRDY and DMA/BREQ high for initial bring-up. If using MRDY with a G7F, T5A, P6F or T6M mask, implement the 4× clock synchronization in Fig. 12(b).

Motorola MC6809 datasheet DS9845-R2, Figs. 6 and 11–12, XTAL/EXTAL and MRDY descriptions

MC6809 DIP-40 wiring map

Highlighted contacts are used in the required step or selected circuit. Select a contact to inspect it.

Top view · Pin 1 at upper left · Schematic outline

Selected pin details

40 · /HALT

Input · Control

Low pauses after the current instruction. BA and BS go high and the CPU releases the bus. Keep both clocks running.

Motorola MC6809 datasheet DS9845-R2, pin assignment and pin descriptions

Electrical limits · Pin in the reference

Models and documents

Covers the Motorola MC6809 and MC6809E plus their A and B speed grades. On the MC6809, E and Q are outputs. On the MC6809E, both are inputs, and pins 33, 36, 38 and 39 also differ. Hitachi HD6309 and later CMOS versions require their own datasheets.

MC6809: 1.0 MHz maximum bus rate. MC6809P/S/L (0–70 °C) and MC6809CP/CS/CL (−40 to +85 °C).
MC68A09: 1.5 MHz maximum bus rate. MC68A09P/S/L (0–70 °C) and MC68A09CP/CS/CL (−40 to +85 °C).
MC68B09: 2.0 MHz maximum bus rate. MC68B09P/S/L (0–70 °C) and MC68B09CP/CS/CL (−40 to +85 °C).

Motorola MC6809 datasheet DS9845-R2· Manufacturer scan, © 1983. Pin map p. 1, electrical and bus timing pp. 2–3, crystal and reset pp. 7–8, ordering p. 35. Scan SHA-256 87037123596de83bbc44ac63fbcde3950d368d5ee30880bffaa54e23bb81ea68.
Motorola MC6809E datasheet DS9846-R2· Manufacturer scan, © 1984. Check the pin assignment, external clock thresholds and timing, TSC timing and ordering table. Scan SHA-256 42c50598f2184bc37535a8d59be60a895c14e34919d706317b18f02f73441808.
Motorola MC6809–MC6809E Microprocessor Programming Manual· Programming model, interrupt handling and vectors. Appendix B lists the two pin assignments side by side.