Finally flashed my SST-DTV

For a long time only the DTV versions with an Atmel Flash ROM can be flashed (You need this to store your own games or custom software). For the newer DTVs with SST Flash there was no software solution known to flash this ROM, too. Actually, a software only solution will never work… You need a small hardware fix – discovered by tixiv from Forum64 – to make everything work…

Hardware fault

The SST Flash compared to the Atmel one is very modern and fast. This results in some kind of pickiness concerning signals that drive it. The DTV has a quite bogus Flash ROM write sequence with two write bursts instead of one (I think the first one is derived from the SDRAM sequence).

SRAM/Flash Write
Clock Cycle 0  1  2  3  4  5  6  7
CPUAddrEn  /----------------------_
nROMCS     ---------_____________/-
nIORD      -------------------------
nWrite     ------_/---_______/----
Address      Row/Col<-Flat Static->

(The diagram is from the DTV Programming Manual)

When sending a Magic sequence to the ROM to enter flash mode, the ROM actually did get two writes for each command and not only one as expected. So the sequence was never detected by the flash and you are unable to ever write anything to it…

… and fix

Tixiv’s idea was now to simply delay the chip enable (/CE) signal to ensure the the flash only registers the second write burst as a valid one. The first one then is silently ignored. The delay can be applied by loading a small capacitor with the /CE line. This is a very easy to install and elegant method to delay some timing…

You need a 48pF capacitor that is soldered between the /CE line to the flash and ground or power… I did the following wiring: (Note that this one is not the simplest solution – but it fit well in my current wiring)

Have a look at Tixiv’s SST Fix if you want to fix your own DTV…

Check it out…

Now it was time to check out if it really works… Just download TLR’s and run the flash_id.prg on your DTV. If everything works well then you get a response from the flash:

… and flash

Unfortunately, TLR’s flash tool did not work out of the box. Tixiv told me that a new version is currently in development and I asked TLR if I might have a look at it… He send me the fresh beta of the 1.0 and it really worked great… I was able to flash the DTVMon, a new custom DTV kernel by Peiselulli and finally I was brave enough to even replace the original kernal with a patched one using TLR’s kernal patcher!

So stay tuned… TLR will release his final 1.0 flash tool soon and you can start flashing your SST DTV! So keep checking his page…

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