SyncMOS Technologies International, Inc.

SM5964A

8-Bit Micro-controller

With 64KB ISP Flash & TWSI & PWM & 1KB RAM embedded

Specifications subject to change without notice contact your sales representatives for the most recent information.

Ver 2.3 SM5964A

10/2006

5

MNEMONIC

PDIP 40 pin

PQFP 44 Pin

PLCC 44 pin

Names and Functions

ALE

30

27

33

Address Latch Enable:

Output pulse for latching the low byte of the address during an

access to external memory. In normal operation, ALE is emitted

twice every machine cycle, and can be used for external timing or

clocking. Note that one ALE pulse is skipped during each access to

external data memory. Setting SFR SCONF.0 can disable ALE. With

this bit set, ALE will be active only during a MOVX instruction.

#PSEN

29

26

32

Program Store Enable:

The read strobe to external program memory. When executing code

from the external program memory, #PSEN is activated twice each

machine cycle, except that two #PSEN activations are skipped

during each access to external data memory. #PSEN is not activated

during fetches from internal program memory.

#EA

31

29

35

External Access Enable:

#EA must be externally held low to enable the device to fetch code

from external program memory locations. If #EA is held high, the

device executes from internal program memory.

X1

19

15

21

Crystal 1:

Input to the inverting oscillator amplifier and input to the internal

clock generator circuits.

X2

18

14

20

Crystal 2:

Output from the inverting oscillator amplifier.