FTDI Community

General Category => General Discussion => Topic started by: Ket3r on February 03, 2021, 12:46:50 PM

Title: FT4222 Spi Slave stops after 48 Bytes
Post by: Ket3r on February 03, 2021, 12:46:50 PM
Anyone else has the problem that you can only fill up the spi slave buffer in the ft4222 with 48 bytes?

I use the ft4222ev board (Rev D Chip) as an SPI Slave. This works fine until I try to write more than 48 Bytes of data to the chip. My Testsetup is a Ft4222EV (slave) connected with an C232HM-EDHSL-0 (master). I observe the SPI communication with an signal analyzer.

If I load the FT4222 with an byte array from 0 to 127 I only receive 0x00 after 48th byte. I attached the code that I use to load the FT4222. I also attached screenshots from the signal analyzer observing the operation.

Is it intended behavior?
Did I miss something in the datasheet?
Anyone else has the same problems?

Best regards,