source: rtems/c/src/lib/libbsp/arm/raspberrypi/README @ 8fbe2e6

4.11
Last change on this file since 8fbe2e6 was c32b1ef, checked in by Alan Cudmore <alan.cudmore@…>, on Mar 23, 2013 at 6:13:07 PM

bsp/raspberrypi: New BSP

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1BSP for the Raspberry Pi ARM board
2This is a basic port that should work on either Model A or Model B.
3
4It currently supports the following devices:
5    o Console using the PL011 UART0
6       The console driver only works with polled mode right now,
7       the interrupt code is there, but it does not work yet.
8       The console driver is currently hardcoded at 115k 8N1
9    o Clock uses the internal ARM timer
10       The Raspberry Pi can be overclocked through the config.txt file, this
11       would affect the duration of the clock tick.
12    o Benchmark timer reads the lower 32 bit GPU timer register
13
14To run an RTEMS binary, it must be stripped and loaded on the SD card along with
15the following files:
16  bootcode.bin
17  config.txt
18  loader.bin
19  start.elf
20  kernel.img ( the RTEMS binary, you can change the name in config.txt )
21
22These files can be obtained from a Linux installation image, or from here:
23https://github.com/raspberrypi/firmware
24
25I used an old 256MB SD card to boot RTEMS.
26Much more information about the SD card file and bootloader can be found here:
27http://elinux.org/RPi_Hub
28http://www.raspberrypi.org
29
30The linker script is set up for 128MB, so it can be used with a GPU/ARM split
31of 128/128.
32The bootloader that is used on the SD card determines the split of RAM between the
33ARM and the GPU. It might make sense to adjust the GPU/ARM memory split to give
34more memory to RTEMS, especially on a 512MB board.
35
36To do:
37    It would be nice to get support in the BSP for the following:
38    o SD card
39    o USB and USB 10/100 network chip on Model B
40    o SPI
41    o GPIO
42    o ARM MMU
43    o Graphics console
44    o Sound
45
46Credits and links:
47
48  There is a wealth of code and information to reference on the raspberrypi.org bare metal forums:
49  http://www.raspberrypi.org/phpBB3/viewforum.php?f=72
50
51  I found information about how to program the timers, interrupts, and UART 0
52  from the examples provided by:
53
54  David Welch:
55  https://github.com/dwelch67/raspberrypi
56  The readme file at his github repository has valuable information about connecting a UART cable, JTAG etc.
57
58  Steve Bate:
59  http://www.stevebate.net/chibios-rpi/GettingStarted.html
60  Steve provided a port of the Chibios RTOS to the raspberry Pi
61
62  James Walmsley:
63  http://www.raspberrypi.org/phpBB3/viewtopic.php?f=72&t=22423
64  James ported FreeRTOS to the raspberry Pi.
65
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