Need buffer full to DMA to USB EP IN? | Cypress Semiconductor
Need buffer full to DMA to USB EP IN?
I am trying hard to understand the difference in the behavior between the bulk auto demo and one app where I set an auto dma between the uart rx and USB EP IN.
In the bulk auto demo, the bytes will be looped back onto the EP IN, no mather how few of them. No need to fill the DMA buffer before hitting the transfer data-IN button. There will be as many as sent, no padding (looked with some analyzer).
In the example I build, there is no way to get any bytes out of the EP before the DMA buffer is full. This seems to be the normal behavior when reading the doc, but I can not explain why the bulk loopback demo "seems" to be different.
My application is a simple DMA AUTO channel between UART (producer) and EP1 (consumer), 16-byte twin buffers (the smallest), infinite transfer, etc.
Any rational explanation for this behavior?
Thx for any help,