LPC55xx : enter ISP mode with UART

[Phil49]

Hi,

I need to enter ISP mode with UART (flexcom 0)

Is it possible when a firmware is already in place on LPC55xx ?

After a reset, I send a "ping" command (5A A6), but I receive no response and the program in place launch.

The default CMPA is in "Auto ISP" mode

How to force CMPA to be in "UART ISP" mode without ISP pin ?

Note : When LPC55xx have no firmware, the "ping" command have a response ACK (5A A7 ...), because the LPC55xx goes into ISP mode automatically

Regards,

Phil

[Alice_Yang]

Hello ,

When the user image in flash is blank or invalid, it will enter ISP mode refer to DEFAULT_ISP_MODE bits defined in Table 170.

It is meaning, if there is a work well image in flash, it won't check DEFAULT_ISP_MODE bits.

BR

Alice

[Phil49]

Hi Alice,

So how can I enter in ISP UART mode (without ISP pin) when I want upgrade my firmware ?

Phil

[danielholala]

how can I enter in ISP UART mode (without ISP pin)

Have a look at the manual UM11126, chapter 6: "LPC55S6x/LPC55S2x/LPC552x Boot ROM".

There it reads:

There are several paths into the ISP mode:

• Entry through the ISP pin assertion.
  – This mechanism is mainly used on EVK boards and customer boards where
  switches and jumpers are affordable in-terms of space and cost.
  – This method is used to recover a part programmed with corrupted image which is
  not detectable by ROM. Once in ISP mode commands are provided to re-program
  the flash with proper image.
• Entry through fall-through mode.
  – When the user image in flash is blank or invalid the ROM enters into ISP mode.
  – This mode of entry allows programming factory fresh parts through ISP interface.
• Entry through ROM API call.
  – Used by application code to implement in field update using ISP mechanism
• Entry through the Debug Mailbox command.
  – This mechanism is mainly used to recover a part programmed with a corrupted image. For instance, on boards/products where the ISP pin mechanism in not affordable and SED pins are accessible or when ISP mode is disabled through the “Default ISP mode” field in the CMPA_BOOT_CFG configuration word.
  – For security sensitive application option to control access to this mechanism is provided through Debug Authentication procedure.