nrf52 SPIS max speed when connected to a HUB

[User1321]

A brief description of my system:

I have a HUB gathering data from the nrf52832 through SPI. The hub is the master and the nrf52832 is the slave. According to the nrf52 specification, the maximum frequency that the SPIS accepts is 8MHz. I have settled in both sides the SPI_mode 3.

When I set the clock frequency to 1MHz, the system works fine i read the data properly, however when in the HUB I increase the SPI speed to 2MHz the data is received on my HUB shifted one bit.

On the oscilloscope I see the clock signal properly but the nRF52 takes outputs its first bit one clock cycle later, therefore I get the data shifted. The HUB has a peripheral output clock capable of 32 kHz, 19.2 MHz and I see the clock signal on the oscilloscope correct.

I have done some tests between two nrf52832 at 4MHz, one as a master and one as slave and it works fine, what could be the reason? Is there any setting that I need to do? any recommendation to fix this issue?

Thanks in advance for your attention,

[Jørgen Holmefjord]

Hi,

It sounds like you could be affected by anomalia 109: DMA: DMA access transfers might be corrupted. Could you check if the workaround described in the PDF document solves the issue?

Best regards,

Jørgen

[User1321]

Ok great! I will read that! does this explain why it works properly when I connect two nordic uC? One as master and one as slave at 8MHz?

[User1321]

I changed the hub's SPI, managing manually the Cheap Select pin, making it go low a bit earlier than the clock and now it works fine, no drifting on the bits!! I also transfer my code to the SDK 13.0. Previously I was working with SDK 11.0!