I'm having some trouble booting an RP2350 on a custom board I've designed.
some details:
- I've designed my PCB closely in tandem with the reference hardware design manual.
- I'm using the W25Q32JVZP flash chip and the recommended crystal. I have no usb connector and intend to rely solely on the SWD interface for flashing.
- I've validated that the internal regulator works fine and outputs a constant voltage at 1.1V so the core should be receiving a stable voltage.
- When I probe the XIN, XOUT, SPI_CS and SPI_CLK pins I see no activity. Suggesting maybe it doesn't get out of the 1st boot stage as it doesn't attempt to access the flash?
- I've added a 10k pullup to the CS pin on the flash, but when I attach power it seems to take around 45ms for the voltage level to rise. Could this be an issue in the sequencing, do I need a more aggressive pull-up?
- I've tested with a second unit of a board to make sure it wasn't a freak manufacturing error.
At this point, I'm a bit stumped as to where to look next as it seems unresponsive which is making debugging a bit tricky. Is there some configuration step I should be aware of? Are there any signals I can measure externally to see where it might be getting to in the bootloader?
Any help would be greatly appreciated and I'm happy to provide any additional details about my setup.
some details:
- I've designed my PCB closely in tandem with the reference hardware design manual.
- I'm using the W25Q32JVZP flash chip and the recommended crystal. I have no usb connector and intend to rely solely on the SWD interface for flashing.
- I've validated that the internal regulator works fine and outputs a constant voltage at 1.1V so the core should be receiving a stable voltage.
- When I probe the XIN, XOUT, SPI_CS and SPI_CLK pins I see no activity. Suggesting maybe it doesn't get out of the 1st boot stage as it doesn't attempt to access the flash?
- I've added a 10k pullup to the CS pin on the flash, but when I attach power it seems to take around 45ms for the voltage level to rise. Could this be an issue in the sequencing, do I need a more aggressive pull-up?
- I've tested with a second unit of a board to make sure it wasn't a freak manufacturing error.
At this point, I'm a bit stumped as to where to look next as it seems unresponsive which is making debugging a bit tricky. Is there some configuration step I should be aware of? Are there any signals I can measure externally to see where it might be getting to in the bootloader?
Any help would be greatly appreciated and I'm happy to provide any additional details about my setup.
Statistics: Posted by OskarP — Sun Nov 09, 2025 8:40 pm — Replies 1 — Views 47