A Serial Programmer for the AT89S52

Licensed under GPLv3

Uses Python 3

Needed Hardware

• Hydrabus (Similar to BusPirate, probably very simple to adapt)

Dependencies

• Python 3
• PySerial

Wiring

• Connect Vcc to 5V and GND to GND (duh)
• Connect SPI, MOSI and MISO between the chip and the Hydrabus
• The AT89S52 needs a clock, so connect an oscillator to XTAL1 and XTAL2
• The reset pin needs 0.7 * Vcc, so connect it to a pullup to 5V and a diode to CS, so when the CS Pin is 0V, the Reset Pin is under 1V. This may not work all the time, use a transistor or something similar in that case

Gotchas

• The hex parser is very basic, only usable for certain types of hex files, for example the ones output by as31
• No checking for the device
• Some delays needed by hardware only provided by slowness of python
• When something fails, the hydrabus may not be properly reset

To be done

• Implement proper hex parsing
  • Maybe use a library
• Solve the problem of flash write waiting a bit nicer
  • Currently, the programm only transfers one byte at a time
• Check chip IDs