AnsweredAssumed Answered

Blackfin SPI DMA-driven with SC16IS750

Question asked by mrgabu on Dec 16, 2013
Latest reply on Feb 1, 2014 by Prashant

Hello guys,

I'm working on a VDK driver for BF518 to communicate with SC16IS750 using SPI.

 

Hardware : ADSP-BF518F ezboard and SC16IS750 custom board.

 

First of all I'm using interrupt mode to configure the bridge IC (SPI to UART) and then I must send a lot of data using FIFO mode write cycle.

Using interrupt to send data is inconvenient, because the TX LVL exceeds 64 bytes (chip limit) very quickly and I have to wait RX answer and then send more data. On my application I can't wait.

 

My idea is use SPI in DMA mode (UART will work at almost 1Mbps and SPI at 5Mbps).

 

As I found on docs (adi_spi_dma.pdf , 8.1.2. Outbound Example), I must start the Driver with ADI_DEV_PDD_ENTRY_POINT but without a ADI_DMA_MANAGER_HANDLE.

 

BTW, I tried without DMA Handler and With DMA Handler.

All of commands returned SUCCESS (for DEV and DMA return codes) but I can't trace any signal on MISO lines using a osciloscope...

Using interrupt everything works as expected.

 

Someone used SPI in DMA mode or can send some considerations to use it with NXP SC16IS750 FIFO write cycle ?

 

Thanks in advanced

Best regards.

Outcomes