Guidance: MibSpi Slave with DMA, transfer data size 255 * 8 bits

Dejan Pojbic

Other Parts Discussed in Thread: RM46L450

Hi,

I need guidance do develop a mibspi slave driver with dma.

I saw the example in help, which is written for master in loopback. To put mibspi in slave mode is no problem.

If i understand correctly, if i want to use DMA, mibspi it must be in multibuffer mode. The RAM for buffer mode is only 128 bytes.

But i want to send and receive 255 bytes. im sending char leng of 8 bits. How to achieve this? Second thing is, that when transfer is complete a interrupt must be set.

Can u help me? Thx.

Im using RM48L950AZWIT.

over 12 years ago

0 Zhaohong Zhang over 12 years ago

TI__Mastermind 22715 points

Dejan,

I would like to recommend you setting up MIBSPI in the compatibility mode and use DMA to move data between MIBSPI RX/TX registers and data buffers defined in system RAM. The attached code example is for SPI master. You can easily changed it for SPI slave.

6607.spi_dma.zip

Thanks and regards,

Zhaohong

0 Dejan Pojbic over 12 years ago in reply to Zhaohong Zhang

Intellectual 480 points

Hi,

thx for the project, i have still some questions aka problems :) . Which settings on DMA are the most important?

I use MIBSPI3 so my DMA request lines should be:

#define SPI3_RX_DMA_REQ 14 /*MIBSPI(Compatibility Mode) RX DMA Request line*/
#define SPI3_TX_DMA_REQ 15 /*MIBSPI(Compatibility Mode) TX DMA Request line*/

Is this true? Can you please give device.h? Its missing on upper zip file.

0 Zhaohong Zhang over 12 years ago in reply to Dejan Pojbic

TI__Mastermind 22715 points

Dejan,

Your DMA request setting is correct. The device.h file is attached here.

5482.device.h

Thanks and regards,

Zhaohong

0 Dejan Pojbic over 12 years ago in reply to Zhaohong Zhang

Intellectual 480 points

Zhaohong,

That means that ONLY those DMA request lines are correct for MIBSPI3?

If select some diffrent lines or channel, DMA will not work?

Best regards,

Dejan

0 Zhaohong Zhang over 12 years ago in reply to Dejan Pojbic

TI__Mastermind 22715 points

Dejan,

DMA request and DMA channel are separate items. DMA requests are signals coming from peripheral modules. You can hook up any DMA request to any DMA channel to perform the transfer. There are only two DAM request from one MIBSPI module.

Thanks and regards,

Zhaohong

0 Dmitri Snejko over 12 years ago in reply to Zhaohong Zhang

Intellectual 745 points

Be honest I am also confused as Dejan. I am working with RM46 and I don't see any notes in the reference manual about fixed DMA request numbers associated with peripherals. Could you post a reference manual page number or a document describing how particular DMA request lines are allocated with peripheral modules.

Regards, Dmitri

0 Zhaohong Zhang over 12 years ago in reply to Dmitri Snejko

TI__Mastermind 22715 points

Dmitri,

You should be able to find informationfrom the device datasheet. For example you can find the table at page100 of RM46L450 datasheet (http://www.ti.com/lit/ds/symlink/rm46l450.pdf). For the request shared by multiple modules, you can only enable DMA request from one of them.

Thanks and regards,

Zhaohong

0 Dmitri Snejko over 12 years ago in reply to Zhaohong Zhang

Intellectual 745 points

Hi Zhaohong,

Thanks, now it became like more clear picture! The request line number at the source and the request line number at DMA are not the same things! I think the reference manual should be more clear on this particular matter.

Regards, Dmitri

0 Charles Johnston over 12 years ago in reply to Zhaohong Zhang

Expert 2690 points

Hello Zhaohong,

I can't download this file (or the associated include file below), even when logged in. Is the link broken or do I need special access?

Thanks, Charlie Johnston

0 Charles Johnston over 12 years ago in reply to Charles Johnston

Expert 2690 points

Hello Zhaohong,

I see my last post was added to the end of the thread, so it may be confusing.

I'm interested in downloading the 6607.spi_dma.zip file and the associated 5482.device.h file to see how to easily transfer > 256 bytes. When I click on the links, I get a Server Error; 403 - Forbidden: Access is denied.

Thanks, Charlie Johnston

0 Zhaohong Zhang over 12 years ago in reply to Charles Johnston

TI__Mastermind 22715 points

Charles,

I uploaded file again here.

5811.spi_dma.zip

Please let me know if it works for you.

Thanks and regards,

Zhaohong

0 Charles Johnston over 12 years ago in reply to Zhaohong Zhang

Expert 2690 points

Zhaohong,

That works perfectly!

Thanks, Charlie Johnston

Arm-based microcontrollers

Arm-based microcontrollers forum

Guidance: MibSpi Slave with DMA, transfer data size 255 * 8 bits