4.4.1. Mixing JTAG devices with JTAG-DP

Existing tools expect JTAG controllers to appear on the main JTAG chain. This method reduces the requirement to modify existing tools, but has the disadvantage that it loses the ability to independently remove power to TAP controllers without stopping the operation of any other TAP controller on the main chain, in this case the DAP. This method of linking devices in series is not recommended for TAP controllers implemented within IEM boundaries that might power- down.

Figure 4.4 shows a core and DAP connected in parallel with JTAG.

Figure 4.4. JTAG core connected in parallel with DAP

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