Yet Better Link(YBLINK) is a pure-Rust CMSIS-DAP v2 probe firmware for HPM5301. The stable build uses USB high speed, FGPIO bit-banged SWD/JTAG, and a CDC ACM USB-to-UART bridge.
Current stable USB identity:
| Field | Value |
|---|---|
| VID:PID | 1209:5301 |
| Product | YBLINK CMSIS-DAP |
| Serial | YBLINK |
| Firmware version | 0.1.0 |
- CMSIS-DAP v2 bulk endpoint, 512-byte USB-HS packets.
- SWD target access on PA27/PA28.
- JTAG target access on PA27/PA28/PA29/PA26.
- Hardware nRESET control on PB10.
- CDC ACM serial bridge on UART0, PA00/PA01.
- UART0 RX uses HDMA with a 96 KiB circular buffer.
The firmware drives the HPM5301EVKLite J3 GPIO header. The target board must be powered normally and must share ground with YBLINK.
| YBLINK signal | HPM5301 pin | J3 pin | Target signal |
|---|---|---|---|
| SWCLK | PA27 | 23 | SWCLK |
| SWDIO | PA28 | 21 | SWDIO |
| nRESET | PB10 | 26 | NRST |
| GND | GND | 25/30/34/39 | GND |
Leave PA26 and PA29 disconnected for normal SWD.
| YBLINK signal | HPM5301 pin | J3 pin | Target signal |
|---|---|---|---|
| TCK | PA27 | 23 | TCK |
| TMS | PA28 | 21 | TMS |
| TDI | PA29 | 19 | TDI |
| TDO | PA26 | 24 | TDO |
| nRESET | PB10 | 26 | NRST |
| GND | GND | 25/30/34/39 | GND |
| YBLINK signal | HPM5301 pin | J3 pin | External signal |
|---|---|---|---|
| UART0 TXD | PA00 | 36 | Target RXD |
| UART0 RXD | PA01 | 38 | Target TXD |
| GND | GND | 25/30/34/39 | GND |
For a loopback smoke test, connect PA00/J3-36 directly to PA01/J3-38.
cargo build -p yblink --release |
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A customized board is also hand-soldered and tested ok, and you can find the sch, pcb and gerber file in hardware_altium_project directory. The five vias are for flashing the firmware(left to the right order: TMS, TCK, TDI, TDO, TRST).
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Install the Rust RISC-V target once:
rustup target add riscv32imafc-unknown-none-elfBuild the release firmware:
cargo build -p yblink --releaseThe output ELF is:
target/riscv32imafc-unknown-none-elf/release/yblink
Flash it with an external probe:
probe-rs download --chip HPM5301 --protocol jtag target/riscv32imafc-unknown-none-elf/release/yblinkA prebuilt firmware is firmware/yblink, you can use probe-rs to download it.