Rockbox Development > New Ports
SanDisk Sansa m200 series (v1)
LambdaCalculus:
Mine is a NAND based... anyone want to trade?
rickbronson:
I've been thinking about this SD NAND bridge. There must be a way to disable the bridge because the TCC770 needs to be able to talk with the NAND directly when it boots. There is no way the TCC770 can boot via SD (that I can tell). So it must be doing this upon boot:
1. SD bridge is wired to NAND and TCC770 is wired to NAND.
2. Upon boot SD bridge tristates output to NAND.
3. TCC770 boots and boots from NAND via direct connection.
4a. Booted software (HARP) detects presence of SD bridge and tristates NAND direct connection and uses SD bridge only.
4b. Booted software (pre HARP) detects no SD bridge and continues to use NAND direct connection.
Make sense?
LambdaCalculus:
Very interesting. :) I think the next step now is find some way of monitoring the boot sequence of a NAND and HARP m200, and comparing the results.
I'll try and see if the OF brings up any juicy info.
shotofadds:
--- Quote from: rickbronson on June 12, 2008, 12:29:43 PM --- I've been thinking about this SD NAND bridge. There must be a way to disable the bridge because the TCC770 needs to be able to talk with the NAND directly when it boots. There is no way the TCC770 can boot via SD (that I can tell).
--- End quote ---
It's a possibility, sure. Although for this to work, the bridge would have to be disabled at reset as I doubt there's any hardware-specific code in the TCC770 boot ROM.
But in that case, the experiment to read the NAND chip id should have been successful.... maybe I'll have a go if/when I get some time next week.
--- Quote from: LambdaCalculus379 on June 12, 2008, 12:43:11 PM ---Very interesting. :) I think the next step now is find some way of monitoring the boot sequence of a NAND and HARP m200, and comparing the results.
--- End quote ---
Might be a good idea to look for differences in the startup code between the v1/2/3.xx firmwares?
LambdaCalculus:
--- Quote from: shotofadds on June 12, 2008, 12:54:43 PM ---Might be a good idea to look for differences in the startup code between the v1/2/3.xx firmwares?
--- End quote ---
A very good idea indeed, shotofadds. I'll try and look for the firmware updaters for each version. I'll let you know if I find anything.
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