Can we use LPC1768 to configure FPGA via JTAG

[marysoniadurom]

My project prototype have LPC1768 Mbed board and Altera Max10M50 development kit. I would like to perform Remote System Upgrade(RSU) on FPGAs using LPC1768 via JTAG.  My idea is to receive FPGS Configuration data from Host PC via UART, store it , then write it to Configuration Flash of Max10 FPGA.

Is that doable?

[kerryzhou]

Hi Mary,

    If you want to use the LPC1768 to control your FPGA via JTAG, you can select some IO pin, then simulate the JTAG control sequence to control FPGA, and write the according code. But I Think you can use the LPC JTAG pin to control the external JTAG device, the on chip JTAG interface is used for the chip debug mode, to chip, it is a slave, but actually, you want to use the LPC as the JTAG master. So you need to prepare the according code. You also need to learn the JTAG protocol.

Wish it helps you!

Have a great day,
Kerry

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[marysoniadurom]

Thank you for your reply.

So LPC1768 has an on-chip JTAG slave device that can be used only for debugging and programming the chip.

Is there any registers associated with JTAG interface like Instruction/Data register that can be accessed?

Do I need to code the entire JTAG protocol from scratch like generating TCK and sampling TDI &TDO?

[kerryzhou]

Hi Mary,

    Unfortunately, the JTAG interface don't have the according instruction/data register for your normal usage in the LPC17XX, so you need to code the entire JTAG protocol.

Wish it helps you!

Have a great day,
Kerry

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