80C552 board


New toy – a Philips PCB80C552-5-16WP based single board computer.

The board is designed to have 64KBytes of EEPROM from 0x0000 to 0xFFFF, 32KB of SRAM from 0x0000 to 0x7FFF and 32KB of peripherals space from 0x8000 to 0xFFFF

On the same board I’ve placed a SPI RTC, EEPROM and 4.096 voltage reference for the on-chip ADC.

The debugging is done via an FTDI usb – serial converter added on the same board.

The PSU is based on a buck converter for the 5V with the possibility to use 5V from the USB port via a jumper.

The board was made using the Eurocircuit’s BINDI pool.

There were 2 bugs after trying to power up, both of them because I failed to properly understand the documentation:

  • the memory space chip select decoder
  • the CS signal to the EEPROM space – the chip does not assert the normal RD line, but PSEN

Both problems where fixed on the first board – the first one by removing the address decoder and rebuilding it on a piece of proto. board, the second one by cutting the RD traces from the EEPROM chips and connecting them to PSEN

After performing those fixes I’ve started working on some basic libraries to cover on-chip peripherals:

  • interrupt driven UART
  • interrupt driven I2C
  • interrupt controller configuration
  • PWM

Thanks everyone from the eeblog forum for their support. Here is the original thread: EEVBLOG forum link

Here are some pictures of the board:

bottom layer top layer top layer _sbc_hotfix

I’ve also attached the schematic – please note that it contains the error I had to fix after getting the board


And for reference the top and bottom copper layers


Category: Electronica, Proiecte
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