LPC Microcontrollers中的主题 Re: GPIO-triggered DMA

GPIO-triggered DMA

lpcware — Wed, 15 Jun 2016 17:48:08 GMT

Content originally posted in LPCWare by anhdung88 on Sun Aug 03 07:45:08 MST 2014
I'm following a project that is streaming image from camera module like this:
http://www.rpg.fi/desaster/blog/tag/lpc1769/
He is using GPIO pins to fetch data from camera but I think when put the processor with more works like streaming it over LAN, the performance is unacceptable.
I wander whether if a mechanism to make DMA transfer from GPIO pins for faster with two questions
1) Does LPC1769 or higher level LPC chips support GPIO DMA transactions?
2) If no direct method found, may I use UART DMA transaction instead? If it's feasible, UART-DMA performance vs using FGPIO (time consume)?

Re: GPIO-triggered DMA

lpcware — Wed, 15 Jun 2016 17:48:09 GMT

Content originally posted in LPCWare by nxp_apps on Sun Aug 03 20:38:03 MST 2014
Hi,

Please refer to application note + software below to DMA data from memory to GPIO.
Hope this helps.

http://www.nxp.com/documents/application_note/AN10850.zip

Thanks,

nxp support

Re: GPIO-triggered DMA

lpcware — Wed, 15 Jun 2016 17:48:10 GMT

Content originally posted in LPCWare by anhdung88 on Mon Aug 04 05:19:26 MST 2014
Thanks for your response, this AN is about timer-triggered DMA, but I mean that is the DMA request triggered by a pin and transactions take place between GPIO pins/port to memory.

Re: GPIO-triggered DMA

lpcware — Wed, 15 Jun 2016 17:48:10 GMT

Content originally posted in LPCWare by HCTEK on Mon Aug 04 07:48:40 MST 2014
Hello,

I did not know if I understand your question. You want a DMA transfer requested by a pin/GPIO and perform that transfer from GPIO to internal memory?

Re: GPIO-triggered DMA

lpcware — Wed, 15 Jun 2016 17:48:11 GMT

Content originally posted in LPCWare by DannyBergh on Tue Aug 05 00:54:23 MST 2014
It think what he means is that he wants to transfer a 8 or 16 bits port using DMA. The trigger moment is an external clock line. So there are multiple IO's for parallel data, and one clock line to synchronize these. I don't know if the MCU has capture inputs and if they are linked with the DMA? Or you could use a less elegant solution and use a timer with an external clock (your sync line) and let it overflow each clock, this timer interrupt can be used by DMA to trigger?