I am unable to connect to the LPC55S28 custom board. my schematics are attached
I am unable to find out any problem with this because I followed the hardware design guide exactly I don't know why its not connecting to jlink.
I am using Jlink commander V8.12, with Jlink version 12
The Jlink is working I am able to connect to other MCU targets. Please help where am I doing the mistake?
I guess its only my misunderstanding of the NXP MCUs. This MCU wont connect to the JLINK either it goes into ISP mode or not I have tried every possible solution but it just does not connect through the JLINK, maybe because this is a chinese JLINK that's why.
The rest of the schematics (other than the ESD diode) is correct I was able to program the board with a USB HID mouse example through the USB and it runs and successfully enumerates, mouse square motion can be seen on PC screen. So after the program uploads through the USB, power cycling this board starts the program if the program is a valid program.
Were you able to resolve the issue? I'm new to NXP world and i'm in the process of designing a custom board so I'm interested in your answer.
I don't have any additional context (so my observation may not be valid), however, i noticed that in your schematics for the TVS diode USBLC6-2SC6, the same data line is not connected to pin 1 and pin 6. In ST datasheet, it shows D+ connecting to 1 and 6, and D- connecting to 3 and 4. Could you comment?
Cheers!
Yes you are correct I removed the ESD IC and it now connects to the PC via USB in ISP mode. I was able to program the MCU through the application. But it is still not working it goes back into ISP mode so I will look into it more when I find out, then I will update.
Hi @mirhamza708
From the schematics provided, the design appears generally aligned with the hardware design guide for the LPC55S28.
1. Test the power supply and signals with an oscilloscope or logic analyzer.
2. Attempt to connect in ISP mode:
• Tie the ISP pin to GND during power-on to force the bootloader to start.
• Then try to connect with J-Link.
BR
Harry
Hi @mirhamza708