2.2 inch tft spi interface, low spi throughput

[caglarabidin]

Hi,

We are trying to interface 2.2 inch 320x240 tft screen via spi on imx6q(pico-pi-imx6). we are able to display video on the screen but we got 5 fps and ~1000KB/s throughput even at 30, 60 MHz spi clks. During the data transmission at high clock speeds, there is a  ~50 us gap between bursts. We believe this is the reason of the low  throughput. My question is how can we reduced the gap between the bursts. Is any modification  required to improve  throughput  for spi transmission? Is it possible to send   continuous  data with 30MHz or higher spi clocks?

Thanks in advance,

[richardallen2]

Are you using DMA or the CPU to drive the SPI?

[caglarabidin]

Hi Richard,

I enabled DMA  option in fbtft driver and checked DMAREG to confirm DMA is enabled.

[igorpadykov]

Hi caglar

max.spi clocks can be found in sect.4.12.2 ECSPI Timing Parameters i.MX6DQ Datasheet

http://www.nxp.com/docs/en/data-sheet/IMX6DQCEC.pdf

In general (if ecspi uses sdma) for reducing gaps one can try to tweak QoS using NIC-301,

described in Table 45-5. QoS and tidemark parameters i.MX6DQ Reference Manual

http://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------