[SOLVED] Automation (SDK) - Using a single JLINK device to access multiple CPUS on JTAG chain

hilamiranda · May 31, 2016 at 4:24 PM

Hello

we are planning a PCB which has 4 M4 CPUs, all connected to one JTAG chain.
Is it possible to use one JLINK device to access all CPUs?

In addition, we use JLink SDK for automation. Can you explain how to use JLink SDK in order to communicate with all CPUs (assuming we close and open communication channel for each CPU)

For example, how to configure so that JLINKARM_Open communicates with a specific CPU.

Many Thanks!

Hila

SEGGER - Niklas · June 2, 2016 at 5:01 PM

Hi Hila,

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Is it possible to use one JLINK device to access all CPUs?

Yes, it is.

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assuming we close and open communication channel for each CPU

Sorry, I do not understand what you want say. What to mean by "channel"?

Quote

For example, how to configure so that JLINKARM_Open communicates with a specific CPU.

JLINKARM_Open() opens a connections to a J-Link, not to a target!
Connecting to the target is done with JLINKARM_Connect().

In order to connect to a specific device in the chain (otherwise J-Link connects to the first device that matches the given target device/core name) you need to specify IRPre and DRPre using JLINKARM_ConfigJTAG().

This is also explained in UM8002.

Best regards,
Niklas

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