MPC5748G JTAG or NEXUS?

[leonardogovoni]

Hallo,

I am brand new to the Qorivva systems and I work on Hardware design using NXP Microcontrollers.

I am building a system with five MPC5748G Microprocessors and I need to design the Program and Debug access ports.

I cannot decide whether to use JTAG oder NEXUS interface. Moreover I want to understand if connecting all the five uCs

with only one debug port (daisy chain configuration) is a good idea or not.

In the Reference Manual I couldn't find enough information.

In the AN5220 Hardware design guidelines they just state how to connect a JTAG, and in the Manual of the development board it is only showed the connectors' pinout. They don't say anything about multiple uCs.

I found a document AN3968 about the Nexus connector relative to the MPC567 family, is it the same for MPC5748?

But no document says anything about Daisy chaining multiple ICs.

Can somebody help me to figure out the best way to debug my system?

Among all the listed debuggers, is there a good price/performances compromise?

thank you very much in advance!

Leonardo

[lukaszadrapa]

Hi,

MPC5748G has Nexus class 3 modules on cores, so it allows you to use data trace if Nexus interface is used.

In short - JTAG allows you to do all standard debugging operations like register read/write, memory read/write, enter debug mode from reset, enter debug mode from running, exit to run mode, single stepping, breakpoints, watchpoints...

If you want to use advanced debugging (watchpoint messages, ownership trace messages, program trace messages, data trace), it is necessary to use Nexus interface.

See this app note for details:

http://www.nxp.com/files/32bit/doc/app_note/AN4591.pdf

Then you can check the schematics for EVB board to see how to connect JTAG/Nexus:

Evaluation System for MPC574xC/G Family|NXP

Daisy chain needs to be supported by debug tool. I have never used it and also I can't remember any customer who used that. If you plan to use S32 Design Studio from NXP, it does not support daisy chain.

If we are talking about debuggers, the best option are tools from www.lauterbach.com. In this case, the part numbers are LA-3500 and LA-3736. It's expensive but the performance beats the price.

Much cheaper option is to use debug probe from PEmicro together with S32 Design Studio:

P&E Microcomputer Systems: Over 30 years as an Industry leader in Embedded Systems Development Tools...

P&E Microcomputer Systems: Over 30 years as an Industry leader in Embedded Systems Development Tools...

Regards,

Lukas

[leonardogovoni]

Hallo Lukas,

Thank you very much for your answer, it was really helpful!

regards

Leonardo