Hi All, Presently we are working on EMAC for MCB2300 Board with LPC2378 uController, with KEIL.
We are implementing a small firmware for sending and receiving the Ethernet frames. While transmitting the Ethernet frames using DMA descriptors, we created only one descriptor and sending the data in application context.First time data is sending correctly next time if we reuse the descriptor we are getting the Tx Err interrupt.
If we use two DMA descriptors it was working without any errors, while using one descriptor and reusing the same descriptor is giving the errors.
For one Descriptor we did the following changes: 1.We initialize the buffer and control word feilds in DMA Descriptor and status also with alignement.
2. Initialize the NoOfDescriptors reg with 0(NoOfDescriptors - 1) and increment the produce index register.Here NoOfDescriptors = 1.
Now we get the TxDone interrupt and verify the values of produce index = 1 , and consume index = 0. when we make produce index = 0, we got the TxFinsih interrupt after that if we send one more frame we got the Tx Error.
Can Anybody made an attempt with one DMA Descriptor for Transmitting the ethernet frame.