How program an external target (LPC11C24) with SWD Connector on OM13093 Board

[arthurtremeau]

Hi every one,

I'm trying to program an external target (LPC11C24) by using the SWD connector on my dev board OM13093.

I don't understand exactly how to use it.

https://www.nxp.com/downloads/en/schematics/LPCXpresso11C24-with-CMSIS-DAP-SCH.pdf

My first try was to connect directly my external target on the SWD Connector and launch my code as Debug Session. Apparently the flash memory of the external target was programmed but not correctly because some of functions doesn't work even though these work perfectly when i only use the dev board OM13093.

After thinking, this method is wird because the CMSIS-DAP interface has 2 targets :

      - LPC11C24 on dev board OM13093

      - LPC11C24 on my custom board

So i think there some troubles between targets and could explain why my code doesn't works on the external target.

Apparently we can use J3 connector on CMSIS-DAP Debug Interface to program an external target. But is it mandatory to seperate the two parts of OM13093 to use it ?

If i understand CMSIS-DAP Debug Interface has two channels with SWD signals. One directly connected to LPC11C24 target and another one on J3 connector.

Is there an issue to use J3 Connector without cut the dev board ?

Plus, are there some precautions to take before use SWD connection ?

On my custom board i just put the same circuit wich on OM13093 (50 Ohms on each signals and 10k pull-up on SWDIO).

thanks for your help

[miguel_mendoza]

Hi Arthu TREMEAU,

In the early LPC boards, you had to cut the trace between the LPC-link and the target to use a JTAG debugger. On later LPCXpresso boards this can be accomplished with a simple jumper setting, in the case of the OM13093 board you have to short the JP3 jumper to allow an external debugger.

Sorry once you separate the part of the LPC11U35 does not support debugging of external targets (at least not easily). The debug section is detachable to support customers who need a smaller form factor for prototyping.

For your own board design, I suggest checking the FAQ: Design Considerations for Debug, have some recommendations and considerations.

Wish it helps you!

regards,
Miguel

[arthurtremeau]

Hi Miguel,

thanks for you feedback, but i'm in trouble. I red what you send me and i don't really found an answer.

I don't understand why we can't connect an external target by using SWD connections as the same way that on OM13093 ?

What is different ?

SWD is just a serial port and CMSIS-DAP the protocol that it used... So really i don't understand.

But if i admit that it's impossible, how could i flash my custom board ?

it makes no sense to me ...

Plus i'm pretty certain to have red that LPC11U35 debug probe allows to flash other target when it splited. But i did not recovery where red it, my bad ...

About JP3, this jumper allows you to desable CMSIS-DAP interface. It's not what i want because i use it to flash my target. Nevertheless, i tried yesterday to dod that and nothing change.

The only thing i want is flash my custom board mounted with LPC11C24. As on OM13093, i provide for SWD connections to connect it directly with Debug probe. But apparently it's not enough.

I don't know if i'm clear in my explanations.

If you have some information on that please help me.

And thank you by the way

Arthur

[miguel_mendoza]

Hi Arthur TREMEAU,

The part of the LPC11U35 of the OM13093 board is only for debugging the LPC11C24, does not support debugging of external targets ( how said, at least not easily), the J3 connector is for flash the LPC11U35,  is not for debugging external targets.  If you split the board or use the JP3 jumper, what could be done is to program the LPC11C24 with an external target through the J5 connector.

For flash you a custom board, I recommended the LPC-Link2  that is an extensible, stand-alone debug probe.

Wish it helps you!

regards,
Miguel

[arthurtremeau]

Hi Miguel,

Thank you for your return.

I'll try with the OM13054 debug probe as you said.

regards,

arthur

[arthurtremeau]

Hi,

I tried to seperate the two parts of OM13093 board but i have new problem, because nothing is detecting by my computer. No debug probe ...

In the schematic, 3v3 power supply is represented on debug probe part but in reality it is on the other part of the OM13093 board .... Consequences are that LPC11U35, used as debug probe, is not powered correctly as VDD pins (pin 6 and 29) are not connected ...

So help me to understand, documentation said that you can split OM13093 board to use LPC11U35 as debug probe with CMSIS-DAP interface. But apparently not ...

Someone has already flash an external target by this way ?

Did i miss something to do it ?

Thanks all