BB v3c and in-circuit SPI flash programming

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BB v3c and in-circuit SPI flash programming

Postby emusic » Sun Mar 22, 2015 8:04 am

Just tried to in-circuit read/write MX25L3206E flash in small "MIFI" router

Connected BB v3c to the IC using a clip with a short DIP-to-SPI cable.

Unfortunately, works very unreliably because CS and SCLK lines of the IC are hardly pulled up and BB due to its output buffer resistors cannot pull them down to the ground (resulting voltage is 2-2.5 V).

Using AsProgrammer (a Russian tool) and USBASP flashed with special AsProgrammer firmware, was able to read/write the IC in-circuit. But AsProgrammer is extremely slow (9 min to read 4MB flash, 25 min to erase-write-verify).

So added two 2N3906 emitter followers to CS/SCLK (200-Ohm resistors from TMS/TCK to bases) and now it works fine and reliably with BB/flashrom, starting from clock divisor 8 (2..4 are unreliable). Less than a minute for full 4MB flash read.
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Re: BB v3c and in-circuit SPI flash programming

Postby maxxproff » Thu Aug 03, 2017 6:51 pm

emusic wrote:...Using AsProgrammer (a Russian tool) and USBASP flashed with special AsProgrammer firmware, was able to read/write the IC in-circuit. But AsProgrammer is extremely slow (9 min to read 4MB flash, 25 min to erase-write-verify)...

Maybe it was because "slow sck" jumper ON.
If "slow sck" jumper OFF, then AsProgrammer works with medium speed.
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Re: BB v3c and in-circuit SPI flash programming

Postby emusic » Tue Aug 08, 2017 12:15 am

maxxproff wrote:Maybe it was because "slow sck" jumper ON.

No, I never soldered JP3.
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