SPIS of nrf52 could not read the data accuracy

[hzhuxin]

I am working with SPIS example ( sdk version 15.3). SPI master send data regulaly. For example, it sent 5ms cs low, but there are only two bytes transferred, the first byte at begin of 5ms, other one at the end. SPIS of nrf52 not read the second one, what can I do with it?

[Edvin]

Hello,

From your main.c file, you have:

APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, 0, m_rx_buf, 1));

Try to increase the length of the receive buffer, which you currently have set to 1.

Can you try:

APP_ERROR_CHECK(nrf_drv_spis_buffer_set(&spis, m_tx_buf, 2, m_rx_buf, 2));

[hzhuxin]

I had tried from 2 to 20, the same result.

[Edvin]

You say that you have created this graph. Are there any simplifications? Is the CLK signal low for the 5ms that no data is sent?

[hzhuxin]

Yes, i create the graph.
but no any info lost.

CLK only had two 8 bits cycle, one at the cs got low, another at before cs to high.

CLK & CS relationship, please check the attachment.

The data in gray box was lost. All other data are no problem.

[Edvin]

Hello,

I assume the yellow line is your CLK and the blue is the MOSI? To me it looks like there is nothing in the MOSI in the yellow box. It looks like it belongs to the 3rd 8 but cycle on the CLK. 

However, where do you set up your SPIS to read? Can you send some snippets?

[hzhuxin]

blue line is CS

I read the SPIS in spis_event_handler, the code were post 3 days ago!

[hzhuxin]

I post another photo to show the MOSI and CLK, so you can clear to read the detail infomation, yellow line is the CLK and blue line is MOSI.

[Edvin]

Hello,

When you set the buffer to 20 bytes (the length), what are the values in the buffer when the event is triggered? 

BR,

Edvin