Next EEHack update

[steveo]

i finally have an ECM and a serial interface working on the bench. i have decided to stop bundling a flash tool with eehack and turn it into a separate (better) tool that'll come with EEHack... i will use this tool as a learning experience for my next project (another flash tool.) stay tuned.

[NomakeWan]

Oooooh I’m excited! Best of luck to you!

[steveo]

HERE WE GO AGAIN

god my brain hurts already

the beer on the right is the most important tool on this makeshift workbench.

IMG_1318.jpg

i keep saying to myself that good things will come of this, even though i never really plan on owning an LT1 again.

[steveo]

step one is to solve the bin scrambling thing that's been driving me nuts for ages.

i've traced the flash to 68k address lines. the following shows the re-ordered lines, so a bit of bit shifting in the indexes in my flash tool should easily convert bins between 'datastream flash' and 'hardware flash' bin formats. here's the t-side magic (lines that are normal not shown):

CPU_ADDRESS,EEPROM_ADDRESS
13,1
12,2
11,3
3,11
2,12
1,13

[steveo]

seems they were nice enough to make t-side and e-side the same, so that formula works for addressing on both sides.

i will now find a reasonably optimal mathematical function to derive the modified address scheme in either direction.

this reminds me of when kur4o gave me a bunch of examples for EE's programming key challenge/response, and it took me a ton of staring to realize that EE's secret programming key was just a NOT gate.

[steveo]

the bits in question we are swapping to derive the correct hardware addressing actually move a mask of 0xE from the low bytes to the high bytes (0xE to 0x000E)

i doubt it's an accident. i think we have found a hilarious GM circuit design easter egg.

[steveo]

i think this will translate 'hard' to 'soft' addressing in $EE bins:

( x & ~0xE00E ) | ((x & 0xE000) >> 12) | ((x & 0xE) << 12)

EDIT: this is not a working example, it fails to reverse the bits, will post a better and more human readable thing soon