On Thu, Aug 3, 2023 at 11:18 AM Yegor Yefremov <yegorsli...@googlemail.com> wrote: > > On Tue, Aug 1, 2023 at 11:44 AM Yegor Yefremov > <yegorsli...@googlemail.com> wrote: > > > > On Mon, Jul 31, 2023 at 1:53 PM Yegor Yefremov > > <yegorsli...@googlemail.com> wrote: > > > > > > I want to write ca. 25 bytes as user data (my FTDI chips are FT2232, > > > FT4232 and FTX). What is my strategy to calculate the user_data_addr? > > > > > > If I set EEPROM defaults via ftdi_eeprom_initdefaults() providing only > > > the product string. Then I perform ftdi_eeprom_build() and use its > > > return value to calculate the user_data_addr like: eeprom->size - > > > user_area_size > > > > > > But this doesn't work as with 128 byte EEPROM (FT2232/4232), the > > > free_end is 26 and thus I get: > > > > > > "Warning, user data overlaps the strings area!" > > > > > > How should EEWriteUserArea() look like in libftdi1? > > > > > > And what about returning an error instead of printing a warning when > > > the user data overlaps with the strings or generated data? > > > > After adding debug output, I can see that free_start for the > > TYPE_2232C chip is at 0x15 and free_end at 0x16. And this doesn't make > > much sense as it is much smaller than user_area_size value. > > > > According to the Application Note AN_121 [1], the user area starts > > after the SerialNumber string (at least for the 128 bytes EEPROMs, > > 256 and 512 bytes EEPROM have another approach). Unfortunately, I > > still cannot find the user area description for the FT-X series. > > > > FT_000071 for the D2XX.dll describes the following routines handling > > the user area: > > > > FT_EE_UASize() > > FT_EE_UARead() > > FT_EE_UAWrite() > > > > This would be useful to have them in libftdi. > > > > [1] > > https://www.ftdichip.com/Documents/AppNotes/AN_121_FTDI_Device_EEPROM_User_Area_Usage.pdf > > [2] > > https://ftdichip.com/wp-content/uploads/2020/08/D2XX_Programmers_GuideFT_000071.pdf > > I have sent two patches [1], [2] that fix the issue for me. The > question is, whether we should spare the byte after "output[i & > eeprom_size_mask] = eeprom->is_not_pnp" for better alignment. Variable > naming and return value of eeprom_build() should be also reworked to > correspond to the FTDI's application note. > > What do you think about it? > > [1] http://developer.intra2net.com/mailarchive/html/libftdi/2023/msg00018.html > [2] http://developer.intra2net.com/mailarchive/html/libftdi/2023/msg00019.html
I finally found FTX memory layout [1] in AN_201. It differs much from the one with an external EEPROM. Compared to the latter, it has fixed areas. For the first implementation, it will be sufficient to implement User Area 1. [1] https://ftdichip.com/wp-content/uploads/2020/08/AN_201_FT-X-MTP-Memory-Configuration.pdf#page=7 -- libftdi - see http://www.intra2net.com/en/developer/libftdi for details. To unsubscribe send a mail to libftdi+unsubscr...@developer.intra2net.com
