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« on: February 20, 2018, 09:46:09 am »
Hi I was wondering if anyone would be able to provide me with a reason the FT4222h is losing bytes.
I am currently using the FT4222h in slave mode, with a microprocessor as master.
The microprocessor sends parcels 6630 bytes every 4ms. Using a Labview program, I poll the "SPI Slave Get Rx Status" and read when there are incoming bytes.
Occasionally the FT4222h has missed bytes and the next parcel has "merged" with the previous parcel.
E.g if i am sending a parcel of 0-6629, one parcel may come up 0,1,2,...4560,4561,90,130,1,25,230,0,1,2,3,...
where 90,130,1,25,230, is the protocol for the packet.
This occurs very infrequently, however I am requiring a high fidelity system, so losing bytes is not ideal.
I have set the latency as 4ms and the Transfer size for USB IN request to 6656 bytes. Slave is set as SPI_SLAVE_WITH_PROTOCOL.