Multi-Programmer With Serial / SPI Programming

Rev A August 2019

Features

• Sockets for direct programming:
  • ATMEGA328P TQFP 32 (via adapter)
  • ATMEGA328P DIP 28 pins
  • ATTINY44/84
  • ATTINY45/85
• Headers for in-circuit programming:
  • Serial Header:
    • 5 pins 2.54mm
  • SPI Headers (too many):
    • 2x3 pins 2.54mm (99% of use)
    • 2x3 pins 1.27mm
    • 1x6 pins 1.25mm (micro-JST)
    • Tag-Connect (mostly useless, since there are no two-ended Tag-Connect cables. Will be removed in future revisions)
• Two programming modes:
  • Serial passtrough
    • Useful to programm chips with Arduino bootloader, or for any USB<->Serial adapter needs
  • ICSP Programming
    • Compatible with Arduino as ISP programmer in Arduino interface
  • Toggle Serial/ICSP mode with pushbutton switch
• USB-B port (could be a downside but I am fond of them: they are sturdy)

Notes

• Socketed chips:
  • ATmega328P running ArduinoISP
  • 555 Used for Mode switch debouncing (old school)
  • PALCE16V8 for mode switching logic (LEDs, pin routing) source
• Optional crystal socket, not needed for new chips (internal clock is used)
  • Required for serial programming if the target is set to use an external crystal (Need to confirm if needed in SPI mode)
• Boots in serial mode, be sure to switch mode to use SPI mode
• Reset button resets the target chip (in both modes) and the Arduino as ISP software
• Don't put more than one target chip at a time (undefined behavior, no protection, might destroy the universe)

Images

Render	Real PCB

Schematics (pdf)

• Complete schematics

PCB Images (svg)

• Top
• Bottom

Future

• Try to combine 555 and programmable logic on Arduino
• Remove useless connectors
• Save mode in EEPROM so it is remembered on next power-up
• LEDs are too bright