README.fads 2.7 KB

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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. Using the Motorola MPC8XXFADS development board
  24. ===============================================
  25. CONFIGURATIONS
  26. --------------
  27. There are ready-to-use default configurations available for the
  28. FADS823, FADS850SAR and FADS860T. The FADS860T configuration also
  29. works for the 855T processor.
  30. LOADING U-Boot INTO FADS FLASH MEMORY
  31. --------------------------------------
  32. MPC8BUG can load U-Boot into the FLASH memory using LOADF.
  33. loadf u-boot.srec 100000
  34. STARTING U-Boot FROM MPC8BUG
  35. -----------------------------
  36. To start U-Boot from MPC8BUG:
  37. 1. Reset the board:
  38. reset :h
  39. 2. Change BR0 and OR0 back to their values at reset:
  40. rms memc br0 00000001
  41. rms memc or0 00000d34
  42. 3. Modify DER so MPC8BUG gets control only when it should:
  43. rms der 2002000f
  44. 4. Start as if from reset:
  45. go 100
  46. This is NOT exactly the same as starting U-Boot without
  47. MPC8BUG. MPC8BUG turns off the watchdog as part of the hard reset.
  48. After it does the reset it writes SYPCR (to disable the watchdog)
  49. and sets BR0 and OR0 to map the FLASH at 0x02800000 (and does lots
  50. of other initialization). That is why it is necessary to set BR0
  51. and OR0 to map the FLASH everywhere. U-Boot can't turn on the
  52. watchdog after that, since MPC8BUG has used the only chance to write
  53. to SYPCR.
  54. Here is a bizarre sequence of MPC8BUG and U-Boot commands that lets
  55. U-Boot write to SYPCR. It works with MPC8BUG 1.5 and an 855T
  56. processor (your mileage may vary). It is probably better (and a lot
  57. easier) just to accept having the watchdog disabled when the debug
  58. cable is connected.
  59. in MPC8BUG:
  60. reset :h
  61. rms memc br0 00000001
  62. rms memc or0 00000d34
  63. rms der 2000f
  64. go 100
  65. Now U-Boot is running with the MPC8BUG value for SYPCR. Use the
  66. U-Boot 'reset' command to reset the board.
  67. =>reset
  68. Next, in MPC8BUG:
  69. rms der 2000f
  70. go
  71. Now U-Boot is running with the U-Boot value for SYPCR.