blob: 0873682787a2d9d4d1ef53af7cd7eb15912323d1 [file] [log] [blame]
wdenk5b1d7132002-11-03 00:07:02 +00001/*
2 * (C) Copyright 2000
3 * Dave Ellis, SIXNET, dge@sixnetio.com
4 *
Wolfgang Denk1a459662013-07-08 09:37:19 +02005 * SPDX-License-Identifier: GPL-2.0+
wdenk5b1d7132002-11-03 00:07:02 +00006 */
7
8Using the Motorola MPC8XXFADS development board
9===============================================
10
11CONFIGURATIONS
12--------------
13
14There are ready-to-use default configurations available for the
15FADS823, FADS850SAR and FADS860T. The FADS860T configuration also
16works for the 855T processor.
17
18LOADING U-Boot INTO FADS FLASH MEMORY
19--------------------------------------
20
21MPC8BUG can load U-Boot into the FLASH memory using LOADF.
22
23 loadf u-boot.srec 100000
24
25
26STARTING U-Boot FROM MPC8BUG
27-----------------------------
28
29To start U-Boot from MPC8BUG:
30
311. Reset the board:
32 reset :h
33
342. Change BR0 and OR0 back to their values at reset:
35 rms memc br0 00000001
36 rms memc or0 00000d34
37
383. Modify DER so MPC8BUG gets control only when it should:
39 rms der 2002000f
40
414. Start as if from reset:
42 go 100
43
44This is NOT exactly the same as starting U-Boot without
45MPC8BUG. MPC8BUG turns off the watchdog as part of the hard reset.
46After it does the reset it writes SYPCR (to disable the watchdog)
47and sets BR0 and OR0 to map the FLASH at 0x02800000 (and does lots
48of other initialization). That is why it is necessary to set BR0
49and OR0 to map the FLASH everywhere. U-Boot can't turn on the
50watchdog after that, since MPC8BUG has used the only chance to write
51to SYPCR.
52
53Here is a bizarre sequence of MPC8BUG and U-Boot commands that lets
54U-Boot write to SYPCR. It works with MPC8BUG 1.5 and an 855T
55processor (your mileage may vary). It is probably better (and a lot
56easier) just to accept having the watchdog disabled when the debug
57cable is connected.
58
59in MPC8BUG:
60 reset :h
61 rms memc br0 00000001
62 rms memc or0 00000d34
63 rms der 2000f
64 go 100
65
66Now U-Boot is running with the MPC8BUG value for SYPCR. Use the
67U-Boot 'reset' command to reset the board.
68 =>reset
69Next, in MPC8BUG:
70 rms der 2000f
71 go
72
73Now U-Boot is running with the U-Boot value for SYPCR.