(please see previous thread for history - PQII/ PQIII Flash Programmer )
Sorry, we do not offer JTAG/COP interface specification to customers, so you can not implement your own flash programmer for PQ2/PQ3 devices using internal debugging interface of PQ2/PQ3 device.
The only thing I can offer here is implement flash programming via standard JTAG commands, i.e. place PQ2/PQ3 device to JTAG boundary scan mode and program external flash, connected to PQ2/PQ3 device by "bit-banging" on PQ2/PQ3 pins using JTAG boundary scan commands. In this case the processor itself will be in reset mode, so you do not need PQ2/PQ3 debug interface description.