Hi, are you planning on debugging bare metal A53 applications, or low level firmware stuff? I don't see the rest of the JTAG pins in the pinmux tables either, and when further reading the RK3328 user manual it seems it's not really JTAG but SWDIO they support with JTAG emulated by the DAP SWJ-DP IP block, which is indeed only a two pin interface described in chapter 11...
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