LPC5528 CFPA and CMPA programming process

[gary_yang]

Hi Sir:

We are a third-party programmer manufacturer.

Currently developing LPC5528 CFPA and CMPA programming process, using ISP Uart.

But at the beginning of sending (0x5A 0xA6) (baud rates 115200), the IC did not respond, it seems that the Uart communication failed

 Our schematic is below, do you have any suggestions?

 

[gary_yang]

Hi Sir：

Our circuit can use SWD to programing Flash,but use Uart to send data (0x5A 0xA6), IC does not respond.

Generally speaking, after the power on,Uart sends data (0x5A 0xA6), will the IC respond? Is there any other process required?

Thanks

[Pavel_Hernandez]

Hello, the LPC5528 does not have any reference for a power sequence or timing. 

• After the bootloader detects the Ping packet (0x5A 0xA6) on UARTn_RX, the bootloader firmware executes the autobaud sequence.

Could you confirm if you have the possibility to check if the signal goes to the MCU in an oscilloscope? to confirm if the 0x5A has integrity.

Best regards,
Pavel

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be supporting your case, I reviewed your information and I recommend reviewing the chapter 6.1 Pin description, I think the method to enter in ISP is missing.

From User Manual.

Let me know if you have more doubts.

Best regards,
Pavel

[gary_yang]

Hi Sir:
ISP0 (PIO0_5 pin) has been pulled low, but send (0x5A 0xA6) (baud rate 115200), IC still does not respond
Is there any other setting required to use ISP mode (UART)?

[Pavel_Hernandez]

Hello, I review your schematic, I recommend reviewing the schematic for the EVK if you want to use the USB and DCDC, in another way I recommend reviewing this app note Hardware Design Guidelines for LPC55(S)xx Microcontrollers (nxp.com). 

The logic state determines the boot source.

Best regards,
Pavel