Macronix MX25R6435F high performance mode - how to activate it?

[kobyfr]

The nRF52840 DK has a 64 mbit external flash on board. The MX25R6435F.

It's performance is too low, in terms of erase speeds - It takes several minutes to erase the entire flash.

We would like to speed that up.

We understand that this is the register to manipulate, for setting the external-flash in "high performance mode", doubling the erase speed.

We also know that the MX25R6435F registers can be accessed like so, as is apparent in the nordic SDK example projects:

    /* Get 3 byte identification value */

    uint8_t rdid_buf[3] = {0, 0, 0};

    cinstr_cfg.opcode = QSPI_STD_CMD_READ_ID;

    cinstr_cfg.length = NRF_QSPI_CINSTR_LEN_4B;

    ret = nrf_drv_qspi_cinstr_xfer(&cinstr_cfg, NULL, rdid_buf);

In what way should we update the configuration register, for achieving our goal of setting the external flash to high performance mode?

[awneil]

You really need to ask Macronix; it's their product - nothing to do with Nordic

[kobyfr]

I did, they gave me the code for a low level driver (which is not based on NRF-SDK), and asked that I consult with nordic...

Hasn't the Nordic team ever set the nRF52840-DK on-board external flash, to high-speed mode?

[awneil]

So is your question about what settings to make, or how to use the nRF52 QSPI interface?

The memory neither knows nor cares what microcontroller you use - the register configurations for setting it to 'high performance' mode will always be the same irrespective of the microcontroller you use.

Macronix are the ones that could tell you what those settings are.

Similarly, the nRF52 QSPI interface neither knows nor cares what peripherals are connected on the bus - sending and receiving stuff always works the same way.

Nordic can tell you how the nRF52 QSPI interface works;  but, presumably, you already have that part working - as you are already using it ?

[kobyfr]

Yes, we are using the DK ext-flash, and a flavor of that Macronix flash on our own circuits.

We have full erase/read/write capability via the QSPI interface.

The ext-flash on our own circuits is a flavor that is already in high-performance mode.

We will receive a batch of low-power ext-flash, and would like to set those to high-performance, in run-time.

Is this the manner to write to the ext-flash registers?

nrf_drv_qspi_cinstr_xfer

?

The method I mentioned above for reading the RDID?

I will inquire with Macronix about the register address of the "configuration register 2" they mention that should be updated.

[awneil]

kobyfr said:

Is this the manner to write to the ext-flash registers?

nrf_drv_qspi_cinstr_xfer

The documentation of that function is here:

https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.0.2/group__nrfx__qspi.html#ga3c1d253949ce90cd1444ab4bf5349471

[kobyfr]

Thanks, but I already read it, and it is not what I asked for.

Let me rephrase:

Your SDK sample applications access the RDID register of the ext-flash, reading its content. That is done via nrf_drv_qspi_cinstr_xfer.
what I ask is this : Can all registers of the ext-flash be accessed using nrf_drv_qspi_cinstr_xfer? 

[awneil]

What does the memory datasheet say is the opcode required for that?

EDIT

nRF Available opcodes seem to be here:

which seem to correspond to Table 5 in the datasheet:

https://www.macronix.com/Lists/Datasheet/Attachments/7913/MX25R6435F,%20Wide%20Range,%2064Mb,%20v1.5.pdf

[kobyfr]

Thanks.

Specifically, this is the sequence to take to modify the configuration register(s):