USB to JTAG+UART downloader

Introduction: Use BL702 to make a USB to JTAG+UART debugger (improved based on the Sipeed open source project)

1. Product introduction

The USB-JTAG debugger can be used on Windows and Linux without a driver, and is used to debug FPGA, C906 and other devices.

2. Application scenario

FPGA program download, simulated
USB to TTL communication

3. Product overview

This product is a USB-JTAG converter based on the Sipeed open source project. It realizes USB to JTAG+TTL by simulating the FT2232 protocol and is used to debug FPGA, C906 and other equipment. Or it has dual serial ports, reserves Bluetooth links, supports secondary development, and is open source code through Apache License 2.0. Please pay attention to its licensing content. The official system has integrated the FT2232 driver. The USB-JTAG debugger is a standard FT2232HL. Theoretically, it is compatible with FT2232 emulation environment and can be used (OpenWrt officially supports FT2232, but it is not sure whether it supports USB2JTAG, but it is certain that it supports USB2DualSerial). The best OpenOCD tool chain [Download OpenOCD by yourself, it is recommended to download from the official website]. If you only use the virtual serial port, you do not need a driver. If unknown hardware appears under Windows, please use a third-party tool to install the driver (such as Driver Wizard). The maximum communication rate of the USB-JTAG debugger is 2.5Mhz. The baud rate supported by the virtual serial port is Up to 2M. The main chip BL702 integrates the BLE function, so the debugger has reserved the corresponding impedance matching circuit and 1206 ceramic patch antenna pad when leaving the factory. If secondary development is required, please refer to the Boliu Intelligence* official website link for the software SDK part. For the hardware part, please go to the Sipeed* download site to obtain the corresponding HDK. Pressing the BOOT button without releasing it and then connecting to the computer will cause the RV debugger+ to enter the download mode. Cooperate with the official Bouffalo tool BLDevCube* to download firmware to the debugger.

4. Product parameters

Power supply voltage: 5V
Supported chips: Gowin FPGA*, Altera FPGA*, Pingtou Ge C906*
working current: 5mA when not supplying power to the target board [6]
Serial port baud rate: maximum baud rate 6M, supports any baud rate**

5. Instructions for use:

Free of charge on Windows and Linux driver use.
The default configuration is serial port + JTAG. If you need dual serial ports, please wait for the subsequent firmware upgrade
. For soldering and use, please refer to the welding and pin definition. For
secondary development of the zip, please visit the Boliu Intelligent official website.

6. Remarks

* Trademarks belong to their respective owners. This article Used for introduction purposes only
** Parameters are theoretical values, please do not use extreme conditions for testing, such as using 6M baud rate for long-term communication or strictly requiring bit error rate, or using extreme baud rates such as 1bps or 1.1bps For rate testing,
this product requires burning firmware. The firmware is in the attachment. Please use the Bouffalo official BLDevCube to burn the firmware. Please press and hold the burning button when burning.
This PCB does not have a silk screen. This is because I am a Death Star person who has a silk screen. However, Don't worry, there are detailed pictures in the attachment welding and pin definition.zip.
The attachment has source code and firmware. The source code comes from the Sipeed open source project, and the firmware is compiled by me.

7. Test video

serial communication test: Communication test under high baud rate.
I have tested it and transmitted it at 1500000 baud rate for 1 hour without errors. This is for reference only. It was not recorded due to market factors.