This document discusses in-circuit programming (ICP) and in-system programming (ISP) of microcontrollers. ICP requires an external programmer connected via a proprietary protocol like SWD to program the flash memory. ISP allows programming the flash without an external programmer by using an onboard bootloader and communicating with the host processor over an interface like I2C, UART, or SPI. The document provides steps to demo ISP using a UART interface by first programming a bootloader, preparing a firmware binary, using ISP tool software to update the firmware over UART, and testing the new firmware.

1. | Photo by Jeffery Cheng
MCU ICP and ISP
2023/06/02

2. Agenda
 In circuit programming (ICP)
 In system programming (ISP)
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3. In-circuit programming of MCU
 Working principle
。 Using Nulink programmer to
program APROM through
proprietary protocol
。 Needs a Nu-Link programmer
。 Nu-link writes data to
APROM via SWD interface
。 Using ICP-tool on PC to
control the NU-link
programmer
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4. In-system programming
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 Working principle
。 No extra programmer needed
。 Write interface from host to target
MCU can be I2C, UART, SPI, CAN,
RS485, USB.
。 Host can be any processor, not
necessarily to be a PC
。 Host communicates with the
bootloader residing in LPROM via
selected interface and writes data to
APROM flash.
。 A bootloader is needed in LDROM
。 Host program can be implemented
on selected processor based on
source codes provided by Nuvoton.

5. ISP demo (1)
 Need to program bootloader into LDROM first
。 Find bootloader sample code, build it, and flash it into LDROM
 M0A21_Series_BSP_CMSIS_V3.01.000SampleCodeISPISP_UARTKEILISP_UART.
uvproj
。 In Keil, Flash -> Configure flash tools -> Utilities -> Settings-> Chip
settings -> Chip booting selection -> LDROM
。 Load bootloader into LDROM.
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6. ISP demo (2)
 Prepare a firmware, which is a .bin file that will be updated to APROM
 Choose another project and build the code to get .bin which will be
needed in next step.
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7. ISP demo (3)
 Download and open ISP tool to
flash firmware (.bin) into
APROM
 https://www.nuvoton.com/too
l-and-software/software-
tool/programmer-tool/
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8. ISP demo (4)
 Update firmware to APROM via UART, not SWD.
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9. ISP demo (5)
 Test new firmware by resetting the board.
 It’s the CAN TX sample code.
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