ESP32 JTAG

USB and WiFi JTAG "cable" for FPGA

USB: Simulate a FT2232H Device

WiFi: Act as an XVC server

JTAG: HW SPI master and SPI slave in byte mode shifting, GPIO in bit mode shifting

Feature

• High speed shifting, with WiFi speeds up to 5M
• Clock adaptable

Test

HW: ESP32S2 <=> SN74AVC4T774 <=> XC7K480T

• Vivado
  • XVC: ✅. Speeds up to 5M
  • USB: ❌. TODO: Known Issues. Will be ported to ch32v30x https://github.com/llcc01/ch32v30x_jtag
• Gowin (TODO)

Sofware Development Environment

ESP-IDF in VSCode

Hardware

ESP32

Any ESP32 with SPI master and slave controller. The SPI clock is connected through the internal mux.

JTAG Wiring

⚠️Level shifting is required. IC: SN74AVC4T774, etc.

// esp32_jtag_idf/main/jtag_dev.c
#define PIN_NUM_JTAG_TDI 39
#define PIN_NUM_JTAG_TDO 40
#define PIN_NUM_JTAG_TCK 41
#define PIN_NUM_JTAG_TMS 42

Button

// esp32_jtag_idf/main/user_io.c
#define GPIO_NUM_SW2 BOOT_BUTTON_NUM
#define GPIO_NUM_SW3 26
#define GPIO_NUM_SW4 21
#define BUTTON_ACTIVE_LEVEL 0

GPIO_NUM_SW2: WiFi configuration

GPIO_NUM_SW3: USB mode

GPIO_NUM_SW4: XVC mode

LED

WS2812

// esp32_jtag_idf/main/user_io.c
#define RMT_LED_STRIP_GPIO_NUM 18

Red Blink: Waiting for mode selection

Blue Blink: Waiting for connection in XVC mode

Blue: XVC mode connected

Green: USB mode

Mode Selection

1. Restart
2. Red Blink
3. Press GPIO_NUM_SW3 to enter USB mode, press GPIO_NUM_SW4 to enter XVC mode

WiFi Configuration

1. Restart
2. Red Blink
3. Press and hold GPIO_NUM_SW2, then press GPIO_NUM_SW4
4. Connect to hotspot ESP32_xxxx
5. Setup in http://192.168.4.1

ref

FTDI

AN_201_FT-X MTP Memory Configuration.pdf

AN_108_Command_Processor_for_MPSSE_and_MCU_Host_Bus_Emulation_Modes.pdf

https://github.com/sipeed/RV-Debugger-BL702

ESP32S2

esp32-s2_datasheet_cn.pdf

esp32-s2_technical_reference_manual_cn.pdf