rtel wrote on Wednesday, January 10, 2007:
Just to go a little further to what John has already stated.
[As I think I state in numerous places on the WEB site and in the code) The sample UART drivers provide an example of interaction between the kernel and an interrupt which is useful for users to copy. However the actual implementation of the driver is often deliberately inefficient, for example it might not use the DMA or even the buffers on the peripheral. This is because the provision of the driver is also for the purpose of testing the port. The more interrupts the peripheral can generate the higher the loading and statistical change of finding an error. If you have a 16 byte buffer and generate an interrupt every 16 characters then you are generating 16 times less interrupts than if you turn the buffering off.