Dataman S4 Programming The 68764

The Motorola 68764 is an early form of 2764 in a 24-pin package. It can be programmed on S4 using a simple adapter.

The adapter consists of 2 stacked sockets. In the following diagram, the outer 2 columns represent the lower, 28 pin socket, and the inner columns the upper, 24 pin socket. The sockets are positioned such that their ground pins (pin 12 upper, pin 14 lower) are aligned. All pins are common except pins 18 upper (20 lower), 21 upper (23 lower) and 24 upper (26 lower), which should not be mated.

  • Pin 18 upper is jumpered to pin 23 lower
  • Pin 21 upper is jumpered to pin 2 lower
  • Pin 24 upper is jumpered to pin 28 lower
  • No connection to pin 20 lower or pin 26 lower
  • Take care that pin 21 upper and 23 lower do not short

S4 Programming 68764 Diagram

The 68764 is placed in the upper socket, and the whole assembly programmed in S4 using the 68764 algorithm.

  • Algorithm details: Rom size: 8k bytes
  • Vcc Program: 5V
  • Vpp Program: 25V
  • Pulse width: 2 milliseconds

Program by applying 25V, 2ms pulses to pin 20 (S4 pin 22)