| Feature | ICP (In-Circuit Programming) | ISP (In-System Programming) |
|---|---|---|
| Full Name | In-Circuit Programming | In-System Programming |
| Purpose | Programs a microcontroller while it is still on the circuit | Programs a microcontroller without removing it from the system |
| Connection Requirement | Requires access to programming pins on the circuit board | Uses standard communication interfaces (SPI, UART, etc.) |
| Typical Usage Stage | Manufacturing/test stage | Field updates and development stage |
| System Power | Often requires external programming power | Uses system power (target board can be powered) |
| Microcontroller State | Can be programmed even if microcontroller is blank | Assumes microcontroller has a working bootloader or interface |
| Tools Used | Dedicated programmer/debugger (e.g., JTAG, SWD) | On-board bootloader, or external programmer via standard I/O |
| Flexibility | Less flexible for field upgrades | More flexible; supports firmware updates without disassembly |
| Hardware Complexity | May require additional programming circuitry | Minimal extra hardware required |
| Examples | Programming via JTAG or SWD interfaces | Programming via USB, UART, SPI using bootloader or firmware |
ICP-dat
If ISP fails or UART is unavailable, consider using ICP via SWD with Nuvoton's Nu-Link debugger.