Usually data communication interfaces are classified to be serial or parallel. Talking about JTAG interface, we can mention briefly that data is transferred in JTAG serially. However, JTAG is explained better as a complete system with four‐wire interface, control logic, instructions register, data registers and even programming and description languages. That is what we can find in this document.
1 - Introduction 2 - Simplified Description 3 - Detailed Description 3.1 - Interface Pins 3.2 - TAP Contents 3.3 - TAP Controller 3.4 - Instruction Register 3.5 - Data Registers 4 - Boundary Scan Description Language 5 - SVF Files 6 - OpenOCD SVF Player 6.1 - OpenOCD Structure 6.2 - Working with OpenOCD 6.3 - OpenOCD Configuration Files 6.4 - Running SVF Files