Hey All,
I hope you can help me. I'm trying to bring up my new board, which contains a STM32N657IO. Attached are the schematics. You can assume the 5V supply is working(it is after a few bodge wires).
My problem is as follows. I'm trying to connect to the STM32N6 over SWD using a JLink. It seems the SWD communication with the Debug port is successful, but the communication with the core fails. I get the following output when trying to connect to the MCU:
Device "STM32N657I0" selected.
Connecting to target via SWD
ConfigTargetSettings() start
---Setting ETM Base Address---
---Setting TF Base Address---
---Setting ETF Base Address---
---Setting TPIU Base Address---
ConfigTargetSettings() end - Took 24us
InitTarget() start
SWD selected. Executing JTAG -> SWD switching sequence.
DAP initialized successfully.
Can not attach to CPU. Trying connect under reset.
SWD selected. Executing JTAG -> SWD switching sequence.
DAP initialized successfully.
Connecting to CPU via connect under reset failed.
InitTarget() end - Took 104ms
Connect failed. Resetting via Reset pin and trying again.
ConfigTargetSettings() start
---Setting ETM Base Address---
---Setting TF Base Address---
---Setting ETF Base Address---
---Setting TPIU Base Address---
ConfigTargetSettings() end - Took 23us
InitTarget() start
SWD selected. Executing JTAG -> SWD switching sequence.
DAP initialized successfully.
Can not attach to CPU. Trying connect under reset.
SWD selected. Executing JTAG -> SWD switching sequence.
DAP initialized successfully.
Connecting to CPU via connect under reset failed.
InitTarget() end - Took 104ms
Error occurred: Could not connect to the target device.
For troubleshooting steps visit: https://wiki.segger.com/J-Link_Troubleshooting
I already investigated the following:
- 1.8V is present
- the 24MHz oscillator is running
- the 0.8V internal SMPS is running and producing 0.8V
- the reset line is high, and the jlink toggles it low while trying to connect
- I used an logic analyzer on the SWD lines, and I can see correct communication until the moment it tries to an R APc followed by an RDBUFF, which is responded with fault.
- Boot0 low or high, doesn't seem to matter
- I tried to connect via the USB ROM bootloader. The host detects an device, but the device never responds to the hosts set address request. (Only host to device communication, no reply)
- I don't see any activity on PG10, which may container bootloader debug output
- I tried to use STMCubeProgrammer, but It doesnt support the STM32N6 using the JLink
- I noticed that I forgot to tie PDR_ON to 1.8V, luckily this ball is in the corner of the chip so I could solder an wire to the ball (thin wire, lots of flux, and heating the wire to melt the solder of the ball to the wire over a small distance, connection seems solid)
These are my remaining ideas:
- Maybe the JLink doesn't support this new MCU correctly. I could buy an ST-Link v3minie
- Something is wrong with my power rails, maybe sequence.
So, my question is. Does anyone have an idea what could be wrong?
