No TWI connection with s100, Dev Kit and BLE

[Pim]

Dear all,

I'm trying to connect the NRF51-DK (PCA10028) with a LSM330DLC accelerometer over TWI (I2C). I'm using the ble_app_uart example, included the twi_master.h file and selected the twi_master (software) in the Run-Time environment.

I call twi_master_init() in the main function. I used the i2c.c wrapper I found here on the forum and using its readI2cReg i'm trying to read a register from the LSM330DLC in order to verify the connection. However, the first twi_master_transfer function returns false, indicating that no data was transferred successfully. I get no further errors and the UART demo still works correctly while running the application.

Can someone please point me in the right direction? Without a clear error I find it very difficult to look in the right place. I added the KEIL5 folder to the post if someone wants to check out the files: ble_app_uart.zip

[Alex]

Are you sure you defined the same pins for TWI communication as LSM connected on PCB?

[Pim]

Alex, I think I did. Default pins according to twi_master_config.h are 24U for Clock Pin and 25U for Data pin. However, on the development board pin 24 is used for the LED so I changed twi_master_config.h to make sure that Clock pin is now 25U and Data pin is 28U. These pins are connected to the LSM. Do I need to change / declare these pins anywhere else?

[i_am_trying]

I'm hoping you wouldn't mind...you're a spot farther with TWI than i am. i am having trouble adding twi to an (example) app. i try both twi_master.h as well as nrf_drv_twi.h..but the build environment (I am using Keil MDK) can't find the files. I add them which adds a slew more of files not found.

Are you using Keil? Could you please share your setup? thank you.

[Alex]

It looks like the I2C address you used is wrong. You have to shift it one bit left

// LSM330D I2C address
// Accelerometer = 001100xb
#define LSM330D_A_ADDR0     0x30  // SA0=0(GND)
#define LSM330D_A_ADDR1     0x32  // SA0=1(VDD)

[Susheel Nuguru]

Pim, can you please update us with your status? Did you manage to fix your issue?