BIOS reference
From Milkymist Wiki
[edit] History
The Milkymist BIOS is based on FreeMAC, originally written for running on the ARM embedded processors of Prism54 Wi-Fi cards. It has undergone major modifications since then.
[edit] Boot process
The BIOS is the first program to be executed by the Milkymist SoC once the FPGA is configured. It is stored into off-chip flash and executed in place. Details of the boot process can be found in http://www.milkymist.org/socdoc/bios.pdf.
[edit] Commands
Bios allow you runs some few commands but very useful if you know how use it:
mr : read address space
mr <address> [length] mw : write address space
mw <address> <value> [count]
Remember when writing values ALL of then are 32 bits, or will be shirked to that size, so if you write:
mw 0xb0000800 0x03 : that’s actually 0x00000003 written in addresses 0xb0000800, 801, 802, 803
mw 0xb0000801 0x03 : that’s actually 0x00000003 written in addresses 0xb0000800, 801, 802, 803
mw 0xb0000800 0x11223344 : that’s actually 0x11223344 written in addresses 0xb0000800, 801, 802, 803
mr 0xb0000800 4 : will return 11 22 33 44 ."3D
mr 0xb0000800 5 : will return 11 22 33 44 00 ."3D.
[count] assumes same length
GPIO Examples for the avnet board port.
mr 0x80001000 8
Read the status of push buttons (try touching some and read at the same time)
mw 0x80001004 1
Put LED 2 on
mw 0x80001004 2
Put LED 3 on
mw 0x80001004 2
Put LEDs off
mw 0x80001004 0