Bus Blaster v4 design overview

Bus Blaster v4 design overview

Bus Blaster v4 is an experimental, high-speed JTAG debugger for ARM processors, FPGAs, CPLDs, flash, and more. Thanks to a reprogrammable buffer, a simple USB update makes Bus Blaster v4 compatible with many different JTAG debugger types in the most popular open source software.

• Based on FT2232H with high-speed USB 2.0
• Buffered interface works with 3.3volt to 1.5volt targets
• Reprogrammable buffer is compatible with multiple debugger types
• Compatible with 'jtagkey', 'KT-link' programmer settings in OpenOCD, urJTAG, and more
• Should support Serial Wire Debug when available
• Mini-CPLD development board: self programmable, extra CPLD pins to header
• Open source (CC-BY-SA)

Bus Blaster v4 is a redesign of v3/v2 that supports SWV, an obscure extension to a reduced pincount JTAG protocol most people will never use. Unless you need it, stick with v3 and save a few bucks!

• Can now support the SWV feature of Cortex microcontroller for advance debugging when software support is available
• SWV is little used and not currently supported in software, most users will be better off with Bus Blaster v4 available here
• Fitted in a DP9056 (90x56 mm) standard PCB
• Added series resistors to input and output pins to protect against damage and noise

Bus Blaster v4 is available now for $45. Each unit is tested with a real JTAG target before it ships.

Buffer logic

New buffer logic is designed using simple schematic entry, Verilog, or VHDL, and the free ISE Webpack software from Xilinx.

• See CPLD development tutorials

Here are two examples of buffer logic to give you an idea how flexible the design can be.

• See Bus Blaster buffer logic for the latest buffers and programming instructions

Buffer logic for Bus Blaster v4 and Bus Blaster v2/v3 ARE NOT COMPATIBLE!

JTAGkey compatible

KT-link compatible