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Diffstat (limited to 'qemu/roms/u-boot/board/fads/README')
-rw-r--r-- | qemu/roms/u-boot/board/fads/README | 73 |
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diff --git a/qemu/roms/u-boot/board/fads/README b/qemu/roms/u-boot/board/fads/README new file mode 100644 index 000000000..087368278 --- /dev/null +++ b/qemu/roms/u-boot/board/fads/README @@ -0,0 +1,73 @@ +/* + * (C) Copyright 2000 + * Dave Ellis, SIXNET, dge@sixnetio.com + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +Using the Motorola MPC8XXFADS development board +=============================================== + +CONFIGURATIONS +-------------- + +There are ready-to-use default configurations available for the +FADS823, FADS850SAR and FADS860T. The FADS860T configuration also +works for the 855T processor. + +LOADING U-Boot INTO FADS FLASH MEMORY +-------------------------------------- + +MPC8BUG can load U-Boot into the FLASH memory using LOADF. + + loadf u-boot.srec 100000 + + +STARTING U-Boot FROM MPC8BUG +----------------------------- + +To start U-Boot from MPC8BUG: + +1. Reset the board: + reset :h + +2. Change BR0 and OR0 back to their values at reset: + rms memc br0 00000001 + rms memc or0 00000d34 + +3. Modify DER so MPC8BUG gets control only when it should: + rms der 2002000f + +4. Start as if from reset: + go 100 + +This is NOT exactly the same as starting U-Boot without +MPC8BUG. MPC8BUG turns off the watchdog as part of the hard reset. +After it does the reset it writes SYPCR (to disable the watchdog) +and sets BR0 and OR0 to map the FLASH at 0x02800000 (and does lots +of other initialization). That is why it is necessary to set BR0 +and OR0 to map the FLASH everywhere. U-Boot can't turn on the +watchdog after that, since MPC8BUG has used the only chance to write +to SYPCR. + +Here is a bizarre sequence of MPC8BUG and U-Boot commands that lets +U-Boot write to SYPCR. It works with MPC8BUG 1.5 and an 855T +processor (your mileage may vary). It is probably better (and a lot +easier) just to accept having the watchdog disabled when the debug +cable is connected. + +in MPC8BUG: + reset :h + rms memc br0 00000001 + rms memc or0 00000d34 + rms der 2000f + go 100 + +Now U-Boot is running with the MPC8BUG value for SYPCR. Use the +U-Boot 'reset' command to reset the board. + =>reset +Next, in MPC8BUG: + rms der 2000f + go + +Now U-Boot is running with the U-Boot value for SYPCR. |