work on a reference debugger for several devices We need to first expose the JTAG pins of the target CPU. There are 3 ways of doing that: 1. Put CPU on a motherboard with XDP, ITP or HDT debug port. 2. Use a top side probe to access top side metal pads of Intel Core family and Intel Second Generation Core family. 3. Solder wires to the JTAG pins of the CPU or JTAG traces on the motherboard. Secondly, we need to send signals of the correct voltage/current and speed to the JTAG pins. We need to use TAP voltages (which are usually Vcore images) and speed. This can be done using a buffer board that incorporates level shifters. JTAG TAP DC electrical specifications are available in CPU datasheets. |
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