Hi there!
I need to make a u-boot config for my custom MPC875-based board.
Until now I just copied everything from esteem192e as it seemed most similar to my hardware to me, and renamed everything to "esm" which is the "codename" of the hardware.
Anyway, I'm not sure if there isn't a board that is more similar to mine which I missed, that's why I'm asking you.
The board will have an MPC875 at 133MHz speed (the first problem, as the u-boot readme doesn't mention a CPU type CONFIG_MPC875, and there also is no CPU of the 870/875/880/885 family available). It'll have an ethernet LXT970A PHY chip and an ISP1301 USB PHY chip for net/usb, plus a three-pin serial interface connected directly to the CPU.
The RAM will consist of 2x K4S561632E SDRAM chips (2*32MB). The 2 chips each take 16bits from the 32bit address bus, chip1 0-15, chip2 16-31. For addressing the adress lines A17-A29 connect to both chips' inputs A0-A12, address lines A6 and A7 connect to the chips' inputs BA0 and BA1.
The flash will consist of 4x AM29LV160D chips, each getting 8 bits of the 32bit data bus, all being connected to the 21bit wide adress bus. Address bus lines A1 to A20 connect to the chips' inputs A0-A19, the chips' inputs called D15/A1 are connected to address bus line A0.
There will be more hardware available on the board, but I won't bother with that as it's not important for the task of getting that PowerPC subsystem running, I suppose.
I could send you schematic diagrams of the layout as graphics if these explanations are not explanatory enough.
The README says of u-boot says for a custom config I'll need a u-boot.lds, a flash.c, a board.c and some more things. Do I need to change anything about the u-boot.lds, the flash.c or the board.c - I hope a custom .../include/configs/ESM.h will suffice?
Thanks in advance,
Peter Asemann