topic Re: Using ISP on LPC55S28-EVK in LPC Microcontrollers

Using ISP on LPC55S28-EVK

steve5528 — Tue, 15 Apr 2025 18:35:11 GMT

Good Day!

I'm having no success to use ISP to download firmware on to the board LPC55S28-EVK.

Board is powered by External +5V power via P5 Micro USB connection.
ISP boot jumper J10 is installed (this jumper ties port P0_5 to ground, forcing the LPC55Sxx into ISP mode whenever it is reset)
Jumper P1 is installed which makes FC0 UART at P8 available for ISP
P8 Flexcom 0 USART is connected to Serial USB Adapter (TX pin -> RX, RX pin -> TX, GND -> GND)

Serial USB adapter is connected to PC, and it appears in device manage on Windows 11.
When reset is pressed, the resident app blinky is not executed so it appears that the ISP mode is enabled.

When Linkflash.exe is run, and refresh button is clicked on its UI, 'Probe' field never gets updated with any entry.
Protocol field remains SWD
Same behavior if FC0/UART is disconnected, and FS USB P10 connector is connected to PC.

The board works fine for flash/debug with onboard debug probe;

How can i make ISP work?

Thank you!

Re: Using ISP on LPC55S28-EVK

Alice_Yang — Wed, 16 Apr 2025 02:16:32 GMT

Hello @steve5528

1> Linkflash.exe tool is not used to program the image based on ISP mode, . Please use Flash Magic or the Secure Provisioning Tool :

https://www.nxp.com/design/design-center/software/development-software/mcuxpresso-software-and-tools-/mcuxpresso-secure-provisioning-tool:MCUXPRESSO-SECURE-PROVISIONING

2>For the ISP-related pins, please refer to the LPC55s28 User Manual.

Alice

Re: Using ISP on LPC55S28-EVK

steve5528 — Fri, 18 Apr 2025 06:42:05 GMT

Hello @Alice_Yang

yes, pin assignments are as you've outlined. When flashmagic is used, the COM port gets detected, however the error "failed autobaud" is preventing image download. I tried 9600 to 115200 baud with no success. what do you suggest?

Thank you.

Re: Using ISP on LPC55S28-EVK

Alice_Yang — Fri, 18 Apr 2025 09:52:16 GMT

Hello @steve5528

Please use the Secure Provisioning Tool to have a try. If it still doesn't work, please send your hardware schematic, and take a video about your steps. I'll help you check.

Thank you.

Alice

Re: Using ISP on LPC55S28-EVK

steve5528 — Mon, 21 Apr 2025 16:42:51 GMT

Hello @Alice_Yang

thank you for the suggestion. I was able to program the MCU with secure provisioning tool the first time. Even though the selection in Boot field was "Plain unsigned", subsequent attempts to write a different image fails with the error "### WARNING - CFPA page already written; can be updated only with higher CFPA version ###" -- the tool by default updates the CFPA even though I did not explicitly select it. How do I disable the version number requirement? the version of the tool is 25.03.

Thank you!

Re: Using ISP on LPC55S28-EVK

Alice_Yang — Thu, 24 Apr 2025 02:41:46 GMT

Hello @steve5528

If you choose "Plain unsigned", even though you flash the CFPA, it doesn't matter. What is flashed is a default value, and it has no impact.

Mainly check whether the connection can be established. Please select "Target" -> "Connection", and then click "Test connection". If the result is "OK", it means that the device has entered the ISP mode.

Alice