Data loss issue in FTDI FT232H and FT2232H Sync 245 FIFO Mode (Part3)
coutinuation of PART2
I examined various signal of FT232H.
And I found TXE# status signal go to Low level without timing of FT_READ.
For example TXE# go to Low when is in FT_OPEN or FT_Purge.
FT_OPEN or FT_PURGE cause reset in FT device, I think. And if WR# fix to TXE# or fix to Low , then something problem occur in the timing of FT_OPEN or FT_PURGE, doesn't it?
Then I change WR# status control to High when FT_OPEN and FT_PURGE. Of course FT_READ go WR# to Low. As below figure.
FTDI's application note （AN-130） (9page) shows 'both of buffer(for TX and RX) has 4k size, but in situation of SYNC 245 FIFO use only dual 512byte FIFO. And 2 FIFO work alternatively' , so I think uncontrol accident cause in loss-data situation.
Once controlled FIFO access achive, data-loss has no appear.
I wish my experience gives someone's help.
thank you.
