I2C Slave with TWI not sending all data

RE: I2C Slave with TWI not sending all data

Simon — Thu, 22 Jul 2021 11:38:43 GMT

I'm glad you got it working and I'm happy to help!

RE: I2C Slave with TWI not sending all data

brandonv — Tue, 20 Jul 2021 14:37:56 GMT

We needed to send the full array at one time instead of each byte individually. The tx_prepare is preparing the full 18 bytes to send at one time. We got it working now. Thank you for the help.

RE: I2C Slave with TWI not sending all data

Simon — Mon, 19 Jul 2021 12:16:00 GMT

For ncs v1.6.0, the TWIM’s prj.conf file needs to be modified.

Replace CONFIG_SPI_1=n with CONFIG_NRFX_SPI1=n in proj.conf

RE: I2C Slave with TWI not sending all data

Simon — Fri, 16 Jul 2021 09:48:02 GMT

Try to remove the printk's between each nrfx_twis_tx_prepare(), also sizeof(zero) will send "\0".

A colleague (Jeff4BLE) created a project to demonstrate how to use an I2C Slave in NCS, check it out here:

devzone.nordicsemi.com/.../blinky_2D00_twim.zip devzone.nordicsemi.com/.../blinky_2D00_twis.zip

"This has been tested with ncs v1.5.1. Extract the attached to \zephyr\samples\basic\blinky-twis

To test the attached, use two nrf52840dks. One as a Master and the other as a Slave.

Connect master’s P0.31 (CLK) to the Slaves P0.27.

Connect master’s P0.20 (SDA) to the slave’s P0.26.

Be sure that the DK’s share a common ground.

Connec the virtual com port on each DK.

To run the tests, first reset the slave and then the master.

TWIM can be built with two configurations. This is selected by changing the value of TWI_LOOPBACK in the main.c (Line 40).

#define TWI_LOOKBACK false.

The master repeatedly sends “From TWIM” to the slave.

The slave cycles through a large message that is sent over multiple read requests from the master."

"#define TWI_LOOPBACK true

The master will first a message “Begin Loopback.” Subsequent messages will be the last message received from the slave."

Some few notes:

It’s not a good idea to leave the printk in the twis_event_handler.
The nrfx_twis_init return values are not thoroughly looked into
In blinky-twis’s twis_event_handler, if printk("\nTWIS READ ERROR\n"); and printk("\nTWIS GENERAL ERROR\n"); are uncommented, these messages are printed. This would seem to indicate that the program is getting TWIS_EVT_READ_ERRORS and TWIS_EVT_GENERAL_ERRORs. I have has time to track this down. However, the program appears to work as expected. So it’s not a high priority. This may be related to 1.

Best regards,

Simon

RE: I2C Slave with TWI not sending all data

brandonv — Mon, 12 Jul 2021 17:38:18 GMT

Simon,

The two appear to have similar function calls to nrfx_twis_tx_prepare() to populate the buffer for transmission.

I am currently calling this function in successive order to transmit the total data. Should there be something in between each call?

RE: I2C Slave with TWI not sending all data

Simon — Sun, 11 Jul 2021 11:23:29 GMT

Sorry for the delay on this.

Have you seen the sample TWIS Slave and TWI Master Mode Drivers Example from the nRF5 SDK? It uses the nrf_drv API instead of the NRFX api, but they should be fairly similar. Looking at that sample, and specifically the file examples/peripheral/twi_master_with_twis_slave/eeprom_simulator.c, you may get an idea how to implement an I2C slave.

If this didn't help, I will investigate your issue more thoroughly.

Best regards,

Simon