[flashrom] ft2232_spi JTAGkey OE disabled for CS high
Ulrich Holeschak
ulrich at holeschak.de
Fri May 20 01:08:46 CEST 2016
Hello,
when using the ft2232_spi driver with Amontec JTAGkey, the OE signal
(bit 4) is disabled
when de-asserting CS:
msg_pspew("De-assert CS#\n");
buf[i++] = SET_BITS_LOW;
buf[i++] = cs_bits;
buf[i++] = pindir;
This means that the CS high signal is floating and the voltage level is
unstable.
Filtering the OE bit fixes this issue:
msg_pspew("De-assert CS#\n");
buf[i++] = SET_BITS_LOW;
buf[i++] = cs_bits & 0x0F; // keep OE active
buf[i++] = pindir;
Regards,
Ulrich
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