Use SPIM to send data to panel, but uint8_t only send 255 byte at a time.

[Coldson]

Hi, I try to send data through SPIM to my panel(Sharp Memory LCM), and I success get the picture (only part of the picture).

The reason why is that function can only support uint8_t, max length 255 byte, but this panel need to send at least 2Kbyte at a time.

(Using function nrf_drv_spi_transfer(&spi, m_tx_buf, m_length, m_rx_buf, m_length)))

Are there any way to send 2K size data through SPI at a time?

Thx for ur kindly help.

Update 1(2016/05/14): I use nrf_drv_spi_transfer() function, send data repeatedly until all data transfer, but it's too lag to display...I will keep study it.

Update 2(2016/05/16): I decided not to use DMA and just replace all tx_buf_length with uint16_t on nrf_drv_spi.c & nrf_drv_spi.h and u can run this panel. nrf_drv_spi.c nrf_drv_spi.h

[James Yu]

Yes you can do it.

1. Control the SS pin manually by configuring it as a GPIO output and and setting it high initially.
2. Break your data into 255 byte chunks
3. Before sending data set SS low.
4. Call nrf_drv_spi_transfer() for first chunk
5. Wait for SPI event handler to know when transfer is complete
6. Repeat 4-5 until all data is transferred, then set SS high.

[Coldson]

Hi, I found that SPIM EasyDMA ArraryList can handle this problem, but I don't know how to use it. Did u use that before? Thx

[James Yu]

Yes it seems that will work as well, although I haven't used it before.

[Coldson]

Hi, I try ur solution, and it work also. Thx.