# RV-Debugger-BL702

**Repository Path**: linjpxt/RV-Debugger-BL702

## Basic Information

- **Project Name**: RV-Debugger-BL702
- **Description**: rv debugger by BL702
- **Primary Language**: C
- **License**: Not specified
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 1
- **Forks**: 0
- **Created**: 2025-04-29
- **Last Updated**: 2026-02-04

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Description

**RV-Debugger-BL702** is an opensource project that implement a JTAG+UART debugger with BL702C-A0.

[BL702](https://www.bouffalolab.com/bl70X) is highly integrated BLE and Zigbee combo chipset for IoT applications, contains **32-bit RISC-V** CPU with FPU, frequency up to **144MHz**, with **132KB RAM** and **192 KB ROM**, 1Kb eFuse, **512KB embedded Flash**, USB2.0 FS device interface, and many other features.

The firmware implement is inspired by [open-ec](https://github.com/rgwan/open-ec), implement by Sipeed teams and community developers.

The firmware emulate an [FT2232D](https://ftdichip.com/products/ft2232d/) device, defaultly implement an JTAG+UART debugger, and can be implement as a Dual-Serial Port debugger, a bluetooth debugger, etc. 

Community Forum:  bbs.sipeed.com

# Hardware
## Offical Board

Sipeed RV-Debugger-Plus  (BL702C-A0)

Purchase link: Aliexpress

Schematic: [BL702_USB2JTAG_3610_sch.pdf](hardware/BL702_USB2JTAG_3610_sch.pdf)

Assembly: [BL702_USB2JTAG_3610_asm.pdf](hardware/BL702_USB2JTAG_3610_asm.pdf)

(LED0 is the led close to edge, indicate for RX)

<img height=480 src="res/rv-debugger.png">
<br />

## Third-party Hardware

TODO

# Firmware
## build firmware

To build usb2uartjtag firmware:

~~~
cd firmware/bl_mcu_sdk
make clean
make BOARD=bl702_debugger APP_DIR=../app APP=usb2uartjtag
~~~

The firmware is './out/app/usb2uartjtag/usb2uartjtag_bl702.bin'.

To build usb2dualuart firmware:

~~~
cd firmware/bl_mcu_sdk
make clean
make BOARD=bl702_debugger APP_DIR=../app APP=usb2dualuart
~~~
The firmware is './out/app/usb2dualuart/usb2dualuart_bl702.bin'.

## flash firmware

Hold "boot" button down, then plug usb cable to PC USB port, and you will see "CDC Virtual ComPort" in device manager , remember the com number.

The flash tool is in tools/bflb_flash_tool directory, and input the command (replace port number and firmware name):

Windows:
~~~
.\bflb_mcu_tool.exe --chipname=bl702 --port=COM9 --xtal=32M --firmware="<path to firmware.bin>"
~~~

Linux:
~~~
./bflb_mcu_tool --chipname=bl702 --port=/dev/ttyACM0 --xtal=32M --firmware="<path to firmware.bin>"
~~~

The output looks like:
~~~
tools\bflb_flash_tool> .\bflb_mcu_tool.exe --chipname=bl702 --port=COM9 --xtal=32M --firmware="main.bin"
[22:07:28.296] - ==================================================
[22:07:28.296] - Chip name is bl702
[22:07:28.297] - Serial port is COM9
[22:07:28.299] - Baudrate is 115200
[22:07:28.299] - Firmware is main.bin
[22:07:28.300] - Default flash clock is 72M
[22:07:28.300] - Default pll clock is 144M
[22:07:28.311] - ==================================================
[22:07:28.483] - Update flash cfg finished
[22:07:28.500] - EFUSE_CFG
[22:07:28.500] - BOOTHEADER_CFG
......
[22:07:31.274] - Load 53856/53856 {"progress":100}
[22:07:31.274] - Write check
[22:07:31.274] - Flash load time cost(ms): 267.942626953125
[22:07:31.275] - Finished
[22:07:31.276] - Sha caled by host: 825d198270c2cf509acda8f8e0830751c532da802060c324a4479e1fe599ae1f
[22:07:31.276] - xip mode Verify
[22:07:31.288] - Read Sha256/53856
[22:07:31.288] - Flash xip readsha time cost(ms): 12.508056640625
[22:07:31.288] - Finished
[22:07:31.288] - Sha caled by dev: 825d198270c2cf509acda8f8e0830751c532da802060c324a4479e1fe599ae1f
[22:07:31.288] - Verify success
[22:07:31.289] - Program Finished
[22:07:31.289] - All time cost(ms): 2220.2548828125
[22:07:31.390] - [All Success]
~~~

Another GUI flash tool is BouffaloLabDevCube:
- [Bouffalo Lab Dev Cube For Windows](https://dev.bouffalolab.com/media/upload/download/BouffaloLabDevCube-1.5.2-win32.zip)
- [Bouffalo Lab Dev Cube For Ubuntu](https://dev.bouffalolab.com/media/upload/download/BouffaloLabDevCube-1.5.2-linux-x86.tar.gz)

## usb2uartjtag (default)

Support JTAG+UART function

UART support baudrate below 2Mbps, and 3Mbps, and some experimental baudrate (stability is not guaranteed):

~~~
12M, 9.6M, 8M, 6.4M, 6M, 4.8M, 4M, 3.2M
we remap baudrate in 10000~12000 to (baud-10000)*10000
for example, 11200bps -> 12Mbps
~~~

LED0 for RX indication, LED1 for TX indication.

JTAG function is verified for :

- RV32 Xuantie E906/E907
- RV64 Xuantie C906
- Gowin FPGA GW1N-1, GW1NS-4C. (need enable GOWIN_INT_FLASH_QUIRK)

## usb2dualuart
TODO.


# Project Structure

```
RV-Debugger-BL702
├── firmware
│   ├── app
│   │   ├── usb2dualuart
│   │   └── usb2uartjtag
│   └── bl_mcu_sdk
├── hardware
├── README.md
└── res
```
BL SDK usage tutorial refer to http://bouffalolab.gitee.io/bl_mcu_sdk/

### Code Explanation
~~~
firmware/app/usb2uartjtag:
├── main.c
├── uart_interface.c
├── jtag_process.c
└── io_cfg.h         //main io cfg, another file is pinmux_config.h in bsp/board/bl702_debugger
components/usb_stack/class/vendor:
└── usbd_ftdi.c      //all FTDI vendor request process, like baudrate set, dtr/rts set, Latency_Timer
~~~