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1 | /* |
2 | * (C) Copyright 2000 | |
3 | * Dave Ellis, SIXNET, dge@sixnetio.com | |
4 | * | |
5 | * See file CREDITS for list of people who contributed to this | |
6 | * project. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation; either version 2 of | |
11 | * the License, or (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
21 | * MA 02111-1307 USA | |
22 | */ | |
23 | ||
24 | Using the Motorola MPC8XXFADS development board | |
25 | =============================================== | |
26 | ||
27 | CONFIGURATIONS | |
28 | -------------- | |
29 | ||
30 | There are ready-to-use default configurations available for the | |
31 | FADS823, FADS850SAR and FADS860T. The FADS860T configuration also | |
32 | works for the 855T processor. | |
33 | ||
34 | LOADING U-Boot INTO FADS FLASH MEMORY | |
35 | -------------------------------------- | |
36 | ||
37 | MPC8BUG can load U-Boot into the FLASH memory using LOADF. | |
38 | ||
39 | loadf u-boot.srec 100000 | |
40 | ||
41 | ||
42 | STARTING U-Boot FROM MPC8BUG | |
43 | ----------------------------- | |
44 | ||
45 | To start U-Boot from MPC8BUG: | |
46 | ||
47 | 1. Reset the board: | |
48 | reset :h | |
49 | ||
50 | 2. Change BR0 and OR0 back to their values at reset: | |
51 | rms memc br0 00000001 | |
52 | rms memc or0 00000d34 | |
53 | ||
54 | 3. Modify DER so MPC8BUG gets control only when it should: | |
55 | rms der 2002000f | |
56 | ||
57 | 4. Start as if from reset: | |
58 | go 100 | |
59 | ||
60 | This is NOT exactly the same as starting U-Boot without | |
61 | MPC8BUG. MPC8BUG turns off the watchdog as part of the hard reset. | |
62 | After it does the reset it writes SYPCR (to disable the watchdog) | |
63 | and sets BR0 and OR0 to map the FLASH at 0x02800000 (and does lots | |
64 | of other initialization). That is why it is necessary to set BR0 | |
65 | and OR0 to map the FLASH everywhere. U-Boot can't turn on the | |
66 | watchdog after that, since MPC8BUG has used the only chance to write | |
67 | to SYPCR. | |
68 | ||
69 | Here is a bizarre sequence of MPC8BUG and U-Boot commands that lets | |
70 | U-Boot write to SYPCR. It works with MPC8BUG 1.5 and an 855T | |
71 | processor (your mileage may vary). It is probably better (and a lot | |
72 | easier) just to accept having the watchdog disabled when the debug | |
73 | cable is connected. | |
74 | ||
75 | in MPC8BUG: | |
76 | reset :h | |
77 | rms memc br0 00000001 | |
78 | rms memc or0 00000d34 | |
79 | rms der 2000f | |
80 | go 100 | |
81 | ||
82 | Now U-Boot is running with the MPC8BUG value for SYPCR. Use the | |
83 | U-Boot 'reset' command to reset the board. | |
84 | =>reset | |
85 | Next, in MPC8BUG: | |
86 | rms der 2000f | |
87 | go | |
88 | ||
89 | Now U-Boot is running with the U-Boot value for SYPCR. |