Rockbox Development > New Ports
Cowon D2
shotofadds:
Ok, so we know there's a difference in LCD and/or backlight handling in some newer D2+ units. Firmware 3.11 works with these as well as older players, so it obviously has a mechanism to detect and work with both types. Someone needs to do some disassembly to work out how this is done in the new firmware.
I'd look into it myself, but I'm about to go away for 2 weeks and I already have plenty of other things to do before then!
shotofadds:
Followers of this thread might be interested in a couple of recent changes:
r22283 re-enables the SD driver, since there have been no more reports of damaged cards.
r22284 implements ECC correction for files read from NAND, which should solve problems with tracks skipping unexpectedly when played from the internal memory.
helloworld1:
--- Quote from: shotofadds on August 12, 2009, 01:59:41 PM ---Ok, so we know there's a difference in LCD and/or backlight handling in some newer D2+ units. Firmware 3.11 works with these as well as older players, so it obviously has a mechanism to detect and work with both types. Someone needs to do some disassembly to work out how this is done in the new firmware.
I'd look into it myself, but I'm about to go away for 2 weeks and I already have plenty of other things to do before then!
--- End quote ---
I can confirm that the backlight cannot be turned on in the new D2+ model. The 2.01 firmware cannot drive the backlight too. But 2.11 2.10 or 3.11 can drive the light. I am using the latest SVN to build the bootloader.
Under very very strong light, I can even see the rockbox logo. So LCD is working but the backlight.
EDIT:
How to dissemable the OF under Linux?, I am willing to help.
shotofadds:
Ok, I spent a couple of hours looking into this today and it looks like some new D2+ units have an entirely different power management chip, instead of the PCF50606 used by older D2+'s and the 'classic' D2.
Looking at firmware 4.11+ (since that is what I use on my player) it shows some interesting changes almost straight away:
- Follow the branch at 0x200000F8 (LDR PC,=0x20009BD4)
- In older firmwares, the first call in this routine starts writing to the PCF50606 almost immediately (using I2C slave address 0x10)
- In 4.11, this now tests the value of GPIOA6 (used for backlight control on older D2s) and stores a flag depending on its value
- Depending on this flag, the next routine (at 0x200722E4) either calls the PCF50606 init routine (0x200BD1C8) or another init routine (0x200BDBE8)
- The new init routine makes numerous I2C writes to slave address 0xE6, with completely different register addresses to the PCF chip.
Similarly, the backlight control routine (0x20072320) checks this flag, and calls either the PCF routine (0x200BD5C4) or a new one (0x200BE19C). To control the backlight brightness, this new routine writes registers 0x28 and 0x29 to I2C address 0xE6.
I don't know what this new chip is - anyone fancy opening their D2+ to find out? Although having said that, this disassembly should give us enough information to get Rockbox working eventually... it's just that I won't be around for the next couple of weeks to look into it.
samokhov:
--- Quote from: shotofadds on August 12, 2009, 04:02:01 PM ---r22284 implements ECC correction for files read from NAND, which should solve problems with tracks skipping unexpectedly when played from the internal memory.
--- End quote ---
It seems to work great so far. I've had a track that only played a few seconds from the start. Now it plays the full 10 minutes. Thanks a ton!
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