Executing out of Winbond serial NOR flash on the MIMXRT1024

[BAW]

Hello,

I am new to the MXRT parts. I have a MIMXRT1024 eval board. There is a "on-chip" Winbond serial NOR flash (W25Q32JV) connected to the processor via the Flex SPI peripheral. It looks like the access speed is 133 MHZ per bit or 16.625 MHZ per byte.

To XIP our application out of the flash would be extremely slow.

Is my understanding incorrect?

Is XIP out of the flash just not something that is done and the flash is just used as a file system where you store your application and run your application out of RAM?

The issue we would have running out of RAM is that our application program size is larger than the 256KB on the part.

Thanks for any insight,

Brent

[BAW]

Thanks for the additional info Lucas.

I just want to understand what the access rate of the flash will be when XIP. This is from the reference manual.

24.4 Quad Serial Peripheral Interface

This chip has one Quad Serial Peripheral Interface block (named FlexSPI) acts as an interface to one or two external serial flash devices, each with up to four bidirectional data lines.

The key features includes:

• Each channel can be configured as 1/2/4-bit operation

• Support both dual-channel or single-channel operation

• Support both SDR mode and DDR mode

• Support up to 166MHz SDR Mode and 166MHz DDR Mode (with external Flash

  device DQS input)

• Support up to 133MHz SDR Mode and 66MHz DDR Mode (with internal DQS

  loopback mode)

Is the configuration for the RT1024 part when configured for Quad mode => clock frequency is 133 MHZ for 4 bits => 133 * 4 / 8 = 66.5 MB/sec or 133 * 4 * 4 / 8 = 266 MB/sec?

Also you mention - " But when you using our SDK with IDE(IAR, MCUXpress, Keil), the flashloader will help you enable the Quad mode."

Can you point me to documentation for this?

Thank you for your help!

Brent

[lucas_cao · Accepted solution]

Hi @BAW 

For quad mode, it should be :

clock frequency is 133 MHZ for 4 bits => 133 * 4 / 8 = 66.5 MB/sec

But when you using our SDK with IDE(IAR, MCUXpress, Keil), the flashloader will help you enable the Quad mode.

I don't know where the document share this information......Maybe some where have that but i don't know.

[BAW]

Thank you for the information. That answers my question.

[BAW]

Thank you for the information.

Can you tell me or point me to the documentation that describes whether the MIMXRT1024DAG5A is utilizing quad mode when connected to its on-chip Winbond serial NOR flash (W25Q32JV)?

Looking at the Winbond documentation below I believe it would be capable of (133MHz x 4) for Quad I/O * 4 / 8 = 266 MB/sec

The W25Q32JV supports the standard Serial Peripheral Interface (SPI), and a high performance Dual/Quad
output as well as Dual/Quad I/O SPI: Serial Clock, Chip Select, Serial Data I/O0 (DI), I/O1 (DO), I/O2, and
I/O3. SPI clock frequencies of up to 133MHz are supported allowing equivalent clock rates of 266MHz
(133MHz x 2) for Dual I/O and 532MHz (133MHz x 4) for Quad I/O when using the Fast Read Dual/Quad
I/O instructions. These transfer rates can outperform standard Asynchronous 8 and 16-bit Parallel Flash
memories.

Is this correct?

Thanks!

[lucas_cao]

Hi @BAW 

I remember that this flash didn't enable the Quad mode by default. But when you using our SDK with IDE(IAR, MCUXpress, Keil), the flashloader will help you enable the Quad mode.

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be supporting your case, the meaning of XIP is executed in place. this means the code can execute from the memory, but the other capability is to charge some tasks in RAM.

Best regards,
Pavel

[BAW]

Hi Pavel,

Thank you for the response. I am sorry if I was not clear in what I was asking. I know XIP is execute in place.

My question is it looks like the access speed of the Winbond serial NOR flash (W25Q32JV) is 133 MHZ / bit or 16.625 MHZ per byte - 500 MHz running in RAM compared to 16.625 MHZ per byte / 8.3125 MHZ per 2-bytes (depending on if it is a one-byte instruction, two-byte instruction, etc.)

And if you have an processor intensive application you would not be able to XIP out of the flash device (just too slow to if you do), you would need to run out of RAM.

Is my understanding correct?

Thanks for your help,

Brent

[lucas_cao]

If the Flash works under Quad mode, the max speed may:

(Max Frequency * 4 / 8 )    MB/s