Subversion Repositories openrisc_2011-10-31

#

#  $Id: README,v 1.2 2001-09-27 12:00:36 chris Exp $

#

BSP NAME:           helas403

BOARD:              IMD, helas-ppc

BUS:                N/A

CPU FAMILY:         ppc

CPU:                PowerPC 403GA

COPROCESSORS:       N/A

MODE:               32 bit mode

DEBUG MONITOR:      Modified Motorola FBUG

PERIPHERALS

===========

TIMERS:             403GA internal

  RESOLUTION:         .04 microseconds

SERIAL PORTS:       403GA internal

REAL-TIME CLOCK:    403GA internal

DMA:                403GA internal

VIDEO:              none

SCSI:               none

NETWORKING:         none

DRIVER INFORMATION

==================

CLOCK DRIVER:       403GA internal

IOSUPP DRIVER:      N/A

SHMSUPP:            N/A

TIMER DRIVER:       403GA internal

TTY DRIVER:         403GA internal

STDIO

=====

PORT:               Console port 0

ELECTRICAL:         RS-232

BAUD:               9600

BITS PER CHARACTER: 8

PARITY:             None

STOP BITS:          1

Notes

=====

Board description

-----------------

clock rate:     25 MHz

bus width:      8-bit PROM, 32-bit DRAM

ROM:            Up to 512KByte (Am29F040), 90 nsec chip select 0

RAM:            4 to 32 MByte DRAM SIMM (autodetect), 70 nsec,

                no parity, at CS7 or CS6+CS7 (for two-bank-SIMMs)

helas403 only supports single processor operations.

Porting

-------

This board support package is written for a typical PPC403GA

system. The rough features of this board are described above.

This BSP contains files for two startup methods:

- Direct start from Flash after powerup (with code run out of flash):

  This is the default configuration, it uses the files

        flashentry/flashentry.s

        startup/linkcmds

 Please note, that this configuration is good to startup the system,

but it will not gain maximum performance due to slow Flash access (8

bit wide only)

- Start after software download into DRAM:

  This configuration will use:

        dlentry/dlentry.s

        startup/linkcmds.dl

If you want to use the download configuration, it is sufficient to

rename the file "startup/linkcmds.dl" to "startup/linkcmds", it will

automatically reference the dlentry.s as entry code. (Renaming is not

quite elegant, a more sophisticated solution will follow in future,

any hints welcome ;-)

For adapting this BSP to other boards, the following files should be

modified:

- c/src/lib/libbsp/powerpc/helas403/flashentry/flashentry.s

        for the memory controller configuration and other basic stuff

- c/src/lib/libbsp/powerpc/helas403/startup/linkcmds[.dl]

        for the memory layout required

- c/src/lib/libbsp/powerpc/helas403/startup/bspstart.c

        for adaption of BSP_Configuration. here you can select

        the clock source for the timers and the serial interface

        (system clock or external clock pin), the clock rates, initial

        baud rate and other stuff

- c/src/lib/libbsp/powerpc/helas403/include/bsp.h

        some BSP-related constants

The actual drivers are placed in

- c/src/lib/libcpu/powerpc/ppc403/*

        well, they should be generic, so there _should_ be no reason

        to mess around there (but who knows...)