SPI Read issue

[Chinna]

Hi,

I am using nRF52832 microcontroller in project. 

I use SPI interface for serial EEPROM.

I could able to see write packets are getting transmitted and verified the signals by probing. SS, SCK and MOSI are perfect.

But when i initiate the Read sequence, I could see the clock is transmitting the Read Instruction Code and Followed by from which address the read should start. Verified the same via probing the signal. But slave is not responding i am seeing continuous HIGH state on the MISO line. Application software read the receive buffer content as 0x00 at all time.

So kindly share your suggestions and possible reasons for fixing this issue.

Note: M95M02 is the serial flash part number that i am using.

Thanks & Regards,

Chinnasamy.

[KevinL]

You say the chip select is always high, but the chip select of SPI is active low. The datasheet says so at page 9 under Chip select.

Have you tried having the chip select low during transmission?

[Chinna]

Hi Kevin,

Yes. I have tried CS LOW during transmission. But it did not worked. 

We are very much close to the problem, Pin 9, 10 are by default NFC pin. But since we connected for CS(P0.10) and MISO(P0.09) purpose for the serial EEPROM interface, we are not able to get the purpose solved because of the NFC default configuration.

But some of the forum says, enable macro  "CONFIG_NFCT_PINS_AS_GPIOS" to configure NFC pins as GPIO pins. Even after enabling the macro same state. we defined "CONFIG_NFCT_PINS_AS_GPIOS" in sdk_config.h.

Kindly share you suggestion on the same. 

Thanks & Regards,

Chinnasamy.

[bjorn-spockeli]

Have you added CONFIG_NFCT_PINS_AS_GPIOS to the Preprocessor Definitions?

[Chinna]

Yes. Added this macro helped me to get P0.09 and P0.10 to configure as GPIO. Now SPI configuration is working fine. But i am not able to read (MISO) data on the receive buffer.