topic Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT in LPC Microcontrollers

LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Laks489 — Fri, 23 May 2025 05:56:41 GMT

How can I expand the storage on the LPC55S69JBD100E using an external SPI flash memory?

The internal flash is not sufficient for my application, so I want to use the FlexSPI interface to connect external NOR flash.

What are the hardware and software steps needed to enable this, and how can I configure it .

Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Harry_Zhang — Fri, 23 May 2025 09:51:55 GMT

Hi @Laks489

unfortunately, the LPC55S69 does not have the FlexSPI interface.

But it has Flexcomm Interface 0 (USART, SPI, I2C, I2S).

You can use it to connect external NOR flash. But this does not support XIP.

Do you need to store data in external flash?

Harry

Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Laks489 — Fri, 23 May 2025 10:02:54 GMT

Do you need to store data in external flash?

No , I need to utilize this External flash memory for code storage .

Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Harry_Zhang — Fri, 23 May 2025 10:17:13 GMT

Hi @Laks489

Even if you can store the code in external flash, this chip does not support XIP.

When you need to execute code, you need to transfer the code to your RAM, which is also relatively small.

So I don't think this can meet your needs.

Harry

Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Laks489 — Fri, 23 May 2025 10:28:42 GMT

Even if you can store the code in external flash, this chip does not support XIP.

If the microcontroller supports XIP, can both QSPI and standard SPI interfaces be used to connect external flash for code storage, or is XIP limited to specific interfaces like QSPI only?

Re: LPC55S69JBD100E - EXTERNAL FLASH SUPPORT

Harry_Zhang — Tue, 27 May 2025 02:54:41 GMT

Hi @Laks489

"If the microcontroller supports XIP, can both QSPI and standard SPI interfaces be used to connect external flash for code storage, or is XIP limited to specific interfaces like QSPI only?"

XIP is generally limited to specialized interfaces like QSPI or FLEXSPI that are designed for high-speed memory-mapped access. Standard SPI cannot be used for XIP due to its lower bandwidth and lack of memory-mapped support.

Harry