QSPI CINSTR Command Read Multiple Bytes

[lufeitan]

Hi,

I am trying to read the SFDP (Serial Flash Discovery Parameter) register of a Micron NOR flash memory using nRF52840 QSPI peripheral. The read SFDP register op code is 0x5A, which I send using the CINSTR command. However, the number of bytes in the register is 128. From my understanding, the maximum number of bytes that could be read back using a CINSTR command is 8 bytes. The values are given in this enum:

typedef enum
{
    NRF_QSPI_CINSTR_LEN_1B = QSPI_CINSTRCONF_LENGTH_1B, /**< Send opcode only. value = 0*/
    NRF_QSPI_CINSTR_LEN_2B = QSPI_CINSTRCONF_LENGTH_2B, /**< Send opcode, CINSTRDAT0.BYTE0. value = 1*/
    NRF_QSPI_CINSTR_LEN_3B = QSPI_CINSTRCONF_LENGTH_3B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT0.BYTE1. value = 2*/
    NRF_QSPI_CINSTR_LEN_4B = QSPI_CINSTRCONF_LENGTH_4B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT0.BYTE2. value = 3*/
    NRF_QSPI_CINSTR_LEN_5B = QSPI_CINSTRCONF_LENGTH_5B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT0.BYTE3. value = 4*/
    NRF_QSPI_CINSTR_LEN_6B = QSPI_CINSTRCONF_LENGTH_6B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT1.BYTE4. value = 5*/
    NRF_QSPI_CINSTR_LEN_7B = QSPI_CINSTRCONF_LENGTH_7B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT1.BYTE5. value = 6*/
    NRF_QSPI_CINSTR_LEN_8B = QSPI_CINSTRCONF_LENGTH_8B, /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT1.BYTE6. value = 7*/
    NRF_QSPI_CINSTR_LEN_9B = QSPI_CINSTRCONF_LENGTH_9B  /**< Send opcode, CINSTRDAT0.BYTE0 -> CINSTRDAT1.BYTE7. value = 8*/
} nrf_qspi_cinstr_len_t;

 

At this moment, I can only read 8 bytes of the 128 byte SFDP register. How can I read all of the bytes in the SFDP register using CINSTR, or is there another method?

Thank you,

Lu Tan

[Simonr]

Hi

Please check out the long frame mode described in the QSPI Driver which will allow for arbitrary byte length which should make it possible to read the full SFDP register using CINSTR reads.

Best regards,

Simon

[lufeitan]

Thank you, Simon.

Do I send nrfx_qspi_lfm_start() first or nrfx_qspi_lfm_xfer() first?

I am thinking

1.  nrfx_qspi_lfm_start() with opcode and length of 1B.

2. nrfx_qspi_lfm_xfer() with read buffer of 128 bytes.

PS: In regards to nrfx_qspi_lfm_xfer(), I am unclear on the final parameter (finalize). It is explained as set "True if custom instruction long frame mode is to be finalized after this transfer." Does this mean set to 1 if the next instruction I want to sent is not long frame and effectively ends long frame mode?

Best regards,

Lu Tan

Edit 1: I just tried to compile the code with the above two functions. I get error that they are undefined?

II have included nrf_drv_qspi.h. Do these functions belong to another QSPI header?

[Simonr]

Hi

The nrfx functions are defined in the nrfx_qspi.h and nrfx_qspi.c files. Please include these and see if you're able to build the project.

Best regards,

Simon

[lufeitan]

Hi,

I was using SDK v15.2.0. Those function are not included in nrfx_qspi.h and nrfx_qspi.c.

Only in SDK v16.0.0 are those functions included in nrfx_qspi.h and nrfx_qspi.c.

Are my observations correct or did I miss something about SDK v15.2.0?

Thanks,

Lu Tan