topic Re: DMA through GPIO or SPI for 30Mhz bit- stream in LPC Microcontrollers

DMA through GPIO or SPI for 30Mhz bit- stream

lpcware — Wed, 15 Jun 2016 18:22:39 GMT

Content originally posted in LPCWare by giladkapel on Fri Apr 10 04:27:41 MST 2015
Hi,

I would like to continuously transfer (just send, no receive, no feedback) array of bytes to one of the pins.
I though of using SPI as I read that there are problems with GPDMA and since the MCU runs at 180Mhz, fastest SPI should be 45Mhz (I just need 30Mhz)
Once the transfer is finished, I would like to execute a callback function and restart the transfer for a different array of bytes.

1. Can the LPC1830 do this?
2. Is there any simple example out there for DMA on SPI?

Thanks for your help

Gilad.

Re: DMA through GPIO or SPI for 30Mhz bit- stream

lpcware — Wed, 15 Jun 2016 18:22:40 GMT

Content originally posted in LPCWare by mc on Tue Apr 14 06:51:00 MST 2015
Hi Gilad,
Please look below SSP example in LPCopen.

Keil IAR:
lpcopen_2_12_keil_iar_ngx__1830\applications\lpc18xx_43xx\examples\periph\periph_ssp

LPCXpresso:
lpcopen_2_12_lpcxpresso_ngx_xplorer_1830\periph_ssp\example

LPCOpen link for LPC1800 is:
http://www.lpcware.com/content/nxpfile/lpcopen-software-development-platform-lpc18xx-packages-0

Re: DMA through GPIO or SPI for 30Mhz bit- stream

lpcware — Wed, 15 Jun 2016 18:22:40 GMT

Content originally posted in LPCWare by giladkapel on Sun May 17 13:07:52 MST 2015
Hi,

Thanks for your help, I was able to get the SPI working in 30Mhz and it looks good.
I have another issue I would like to ask about.
I was only able to send 8bit or 16bit words. I need to send a 'word' which is 392bits long.
I can send this large word in chunks of 8bit or 16bit but I prefer to send it as a long stream of bits.
Is this possible using the LPC1800? All I need is a stream of bits from memory (DMA) and a 30Mhz clock.

thanks again for your help

Gilad.