AMP FlashProg

This is an alternate firmware for the AMP or BMP which uses it as a SPI flash programmer, interfaced over USB serial.

Pinout

          ______
  VTref --|1  2|-- SWDIO/TMS....FLASH MOSI
    GND --|3  4|-- SWDCLK/TCK...FLASH SCLK
    GND --|5  6|-- SWO/TDO......FLASH CS
        x-|7  8|-- TDI..........GPIO
    GND --|9 10|-- nRST.........FLASH MISO
          ------

GPIO is controlled over the serial port and may be used for e.g. holding an FPGA in reset while writing to its flash memory.

Protocol

The serial port transmits and receives ASCII-coded data.

Transmit	Effect
0x67 g	Sets GPIO low
0x47 G	Sets GPIO high
0x73 s	Sets CS low
0x53 S	Sets CS high-impedance (typically then pulled high)
0x6d m	Sets default flash-programming mode (MOSI out, MISO in)
0x4d M	Sets FPGA-programming mode (MOSI in, MISO out)
0x70 p	Disables target power (default)
0x40 P	Enables target power
0-9, a-f, A-F	Data nibbles to transmit
Anything else	No effect

Each nibble is transmitted upon reception and the four data bits received on the SPI bus are then sent back as a hex character over the serial port.

The MOSI and SCLK pins are high impedance when not actively transmitting data, with SCLK pulled up.