Hi.
The TRM describes that we can configure TXSIZE of uPP as follows:
UPTCR:TXSIZEA
0-3h Transmit threshold for Channel A. Controls the number of bytes that interface Channel A waits before beginning transmission. Only applies when Channel A is configured in transmit mode using the MODE bit in the uPP channel control register (UPCTL).
0 : 64 bytes <= Question: Can we use this setting for DMA descriptor byte count greater than 64?
1 : 128 bytes (requires DMA descriptor byte count greater than 64)
2h: Reserved
3h: 256 bytes (requires DMA descriptor byte count greater than 192)
When we transfer data less than 64 byte-counts, do we need to configure TXSIZE >= 1?
My customer is seeing the under-run error when he transfers 260 byte-counts with TXSIZE=0.
He'd like to identify the cause of the error. 260 byte-counts with TXSIZE=0 is not allowed? Or his system may be overloaded to handle the DMA?
Best regards,
Tsutomu Furuse
