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comparison doc/FTDI-EEPROM-tools @ 51:311c800268b8

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doc/FTDI-EEPROM-tools: added note about bigger EEPROMs not providing any more room for strings
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 22 Apr 2019 23:28:27 +0000
parents b2e9a6f3c833
children 0514e3520be3
comparison
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50:fc6f64fb5714 51:311c800268b8
192 still 128 words long just like with -b, as that is what FT2232x chips apparently 192 still 128 words long just like with -b, as that is what FT2232x chips apparently
193 expect. I said "apparently" because I don't have any FT2232x hardware with 193 expect. I said "apparently" because I don't have any FT2232x hardware with
194 93C66 EEPROMs and I don't plan on acquiring or building any, hence this minimal 194 93C66 EEPROMs and I don't plan on acquiring or building any, hence this minimal
195 93C66 support is completely untested - use at your own risk. 195 93C66 support is completely untested - use at your own risk.
196 196
197 It also needs to be noted that with our current RE-based understanding of FTDI's
198 undocumented EEPROM structure, using a bigger EEPROM does NOT provide more room
199 for strings: all that happens with -b and -B options is that a gap of 64 unused
200 EEPROM words is inserted between the end of the fixed structure and the
201 beginning of strings. The exact same arrangement has been observed in all 93C56
202 EEPROM images found in the wild, presumably produced with FTDI's official tools,
203 including FTDI's own USB-COM232-PLUS2 board - thus it is not clear at all if
204 FT2232x chips actually support longer strings with bigger EEPROMs, and if not,
205 what does one need a bigger EEPROM for...
206
197 For the format of config files read by our ftee-gen2232[ch] tools and what 207 For the format of config files read by our ftee-gen2232[ch] tools and what
198 settings can be tweaked, read the source code. 208 settings can be tweaked, read the source code.
199 209
200 Erasing the EEPROM (making it blank) 210 Erasing the EEPROM (making it blank)
201 ==================================== 211 ====================================