Conditions for NRFX_SPIS_XFER_DONE event Trigger

[mystic_harbor]

I am using SPIS for my project. I am manually toggling CS for the peripheral. I get NRFX_SUCCESS for nrfx_spis_buffers_set() function. Also, when I probe the CS signal on oscilloscope, I see that CS transitions from low to high state. However, I am not getting NRFX_SPIS_XFER_DONE event.

My code is looking for NRFX_SPIS_XFER_DONE event to proceed further. I am not sure what will make  NRFX_SPIS_XFER_DONE event to get triggered as I have buffers set appropriately (getting NRFX_SUCCESS) and also CS going to High state. 

I am using NRF53 with nrfConnect SDK

[Einar Thorsrud]

Hi,

The NRFX_SPIS_XFER_DONE events occurs after a END event in the peripehral itself (see product specification for details). Based on what you write, you are just testing with toggling CS, and not actually having a SPI master? The slave does not generate it's own clock, so if you don't have a master (real or dummy) that drives the clock, there will not be any transactions.

[mystic_harbor]

I am using NRF5340 as SPI slave and an image sensor as SPI master. I am getting all signals from the sensor. CS also gets toggled from Low to High state and the data output from the camera is fed to MOSI pin. However, when I printed the rx_buffer, it's not getting updated, but I am getting NRFX_SUCCESS for nrfx_spis_buffers_set(). Maybe this is the reason why I am not able to get NRFX_SPIS_XFER_DONE event. How can this be resolved

Below is my prj.conf

# GPIO
CONFIG_GPIO=y

# I2C
CONFIG_I2C=y

# Log
CONFIG_LOG=y

# Bluetooth
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_GATT_CLIENT=y
CONFIG_BT_DEVICE_NAME="Test"
CONFIG_BT_DEVICE_APPEARANCE=833
CONFIG_BT_MAX_CONN=1
CONFIG_BT_MAX_PAIRED=1
CONFIG_BT_BUF_ACL_RX_SIZE=502
CONFIG_BT_ATT_PREPARE_COUNT=2
CONFIG_BT_L2CAP_TX_BUF_COUNT=10
CONFIG_BT_L2CAP_TX_MTU=498
CONFIG_BT_CONN_TX_MAX=10
CONFIG_BT_BUF_ACL_TX_COUNT=10
CONFIG_BT_BUF_ACL_TX_SIZE=502
CONFIG_BT_USER_DATA_LEN_UPDATE=y
CONFIG_BT_USER_PHY_UPDATE=y
CONFIG_BT_HCI_CORE_LOG_LEVEL_INF=y
CONFIG_BT_RX_STACK_SIZE=8192

# GPIOTE
CONFIG_NRFX_GPIOTE=y
# The below command is needed to include multiple GPIOTEs (FRAME_VALID, LINE_VALID).
# Else, the configuration of GPIOTE initialized second would fail. Only the first one would work
CONFIG_NRFX_GPIOTE_NUM_OF_EVT_HANDLERS=2

# Timer
CONFIG_NRFX_TIMER0=y
CONFIG_NRFX_TIMER1=y

# SPI
CONFIG_SPI=n
CONFIG_NRFX_SPIM2=n
CONFIG_NRFX_UARTE2=n
CONFIG_NRFX_SPIS2=y

CONFIG_LOG_BUFFER_SIZE=10000

[Einar Thorsrud]

I am not able to say much based on just your config, Can you share the code as well? Also, if you need a simple example of using SPI slave, you can look at this unoficial sample that includes a slave and a master. This use the Zephyr API, but there are also samples using nrfx directly under modules/hal/nordic/nrfx/samples/src/nrfx_spim_spis/ in the SDK.

[mystic_harbor]

modules/hal/nordic/nrfx/samples/src/nrfx_spim_spis/- This is the example I referred to implement.

I have attached the complete code in a private ticket.

Thanks!

[Einar Thorsrud]

Hi,

My collaegue Torbjørn is handling the other case and I see you have good progress. The only thing I notice is that in that case it seems like you want the nRF to act as SPI master, and in that case, using SPIS (slave) will nto work. With that approach, it seems you want to have one slave talk to another slave, but that is not how SPI works. You need to have a master on the bus. And that should be the nRF in this case.

[mystic_harbor]

Thank you for responding.

No, I want to use nRF as SPI Slave itself. I only mentioned that <NRF_PSEL(SPIS_CSN, 1, 12)> command in overlay file doesn't work for SPIS and works only for SPIM. if its included when SPIS is enabled, it throws build error

[Einar Thorsrud]

Hi,

OK. So another (or he same?) nRF is acting as an SPI master in addition to the SPI slave, then? I think we need to back-track a bit so that we get a better understanding of the basics of what you are doign here. I suggest we continue with that in the other thread for now, and then we can update here with the conclusion.