Error -In dma data transfer

Hi, Nirav.

In my opinion your problem comes from using the DMA API calls from inside an ISR. The following excerpt from the Nios II SW programmer manual, chapter 6 should help you in understanding:

Restricted Environment

ISRs run in a restricted environment. A large number of the HAL API

calls are not available from ISRs. For example, accesses to the HAL file

system are not permitted. As a general rule, when writing your own ISR,

never include function calls that can block waiting for an interrupt.

In addition, you should be careful when calling ANSI C standard library

functions inside of an ISR. No calls should be made using the C standard

library I/O API, because calling these functions can result in deadlock

within the system, i.e., the system can become permanently blocked

within the ISR. In particular, you should not call printf() from within

an ISR without careful consideration. If stdout is mapped to a device

driver that uses interrupts for proper operation, the printf() call can

deadlock the system waiting for an interrupt that never occurs because

interrupts are disabled. You can use printf() from within ISRs safely,

but only if the device driver does not use interrupts.

Hope this helps.

Maurizio