Hello,
The programming algorithm is vaguely listed in the data book, but the precise meaning of some of the steps is unclear.
- Switch S1 powers up the device.
- Software synchronizes the external oscillator to the internal clock.
- Switch S2 applies Vpp to the IRQ/Vpp pin.
- Software sets the ELAT bit (EPROG register).
- Software writes to an EPROM/OTPROM address.
- Software sets the EPGM bit for a time tEPGM, to apply the programming voltage.
- Software clears the ELAT bit.
D0 to D7 of the parallel port are connected to PA0 to PA7 of the device.
/Strobe -> /RESET
Ack -> PB0, with 2k2 pullup
PE -> PB1, with 2k2 pullup
Init -> OSC1, with 220R pullup
IRQ/Vpp switched to 0 volt, or Vpp
Vcc switched to 0 volt, or +5 volt
The relationship between the various operations, and the manipulation of the pins, is not detailed. My guess is that this device predates any Freescale involvement.
Regards,
Mac