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著者：佐藤 仁矢(著)　個人出版　2026/10/5(月)配信

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905 nm laser rangefinder module driver — erdilrf.com - yu911517778-a11y/ErdiLRF

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Thank you! Rotating the plug did the trick, with much less force!

The picture clearly shows a connector that is far from being pushed in completely. If you cannot insert it without a lot of [dangerously high] mechanical force, then you likely have a plug that’s somehow broken / too thick / out-of-spec or a jack that is broken. Try pushing the plug in while slowly rotating it, and while putting pressure on the jack towards the circuit board (pushing the jack down on the board).

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That narrows it down. The cable is fine, and in raw mode nothing from the board reaches it. The garbage under make log was most likely the tty echoing its own bytes in a loop through a tip-to-ring short. A plug that isn’t fully seated does exactly that, because its tip rests on the ring contact. 1. Confirm it: unplug USB so the SIMtrace2 is off, leave the plug where it is now, run picocom -b 921600 /dev/ttyUSB0 and type. If what you type comes back, tip and ring are shorted inside the jack. 2. Don’t force the plug. Fully seated, no metal shaft shows and the collar sits flat against the jack, but in your photo a band of metal is still outside. 3. Bypass the jack using the P2 DEBUG header with any 3.3 V USB-UART adapter: * pin 1 GND * pin 4 (board TX) to the adapter’s RX * pin 5 (board RX) to the adapter’s TX 4. Solder a header strip, or for a quick test press jumper wires into the holes at an angle. Then run stty -F /dev/ttyUSB0 921600 raw -echo; cat /dev/ttyUSB0 and press reset. If the banner shows on the header, J2 is the fault. Keep using the header, or replace the jack.

1. Echo works fine 2. It doesn’t print anything 3. How far in should I push it? I can’t push it much more and I am putting a lot of pressure so I don’t want to break it. 4. It’s not the image. I am building `make TRACE_LEVEL=5 BOARD=simtrace APP=trace`

The firmware side is fixed: the simtrace board image runs its debug UART at exactly 921600 8N1, from a 58.9824 MHz master clock with divisor 4. Steady garbage therefore points at the cable, the jack or the wrong board image. Check them in this order: 1. Loopback the cable alone. Unplug it from the SIMtrace2, short tip to ring on the 2.5 mm plug, run picocom -b 921600 /dev/ttyUSB0 and type. A clean echo means the cable and driver are fine at 921600. Garbage means the cable is at fault. 2. Read in raw mode with echo off. make log only sets the speed, so the tty stays in cooked mode with echo on and feeds everything it receives back into the board’s console. Run stty -F /dev/ttyUSB0 921600 raw -echo, then cat /dev/ttyUSB0, and press reset. You should see the “SIMtrace2 firmware …, BOARD=simtrace, APP=trace” banner. 3. Push the plug fully home. A half-seated 2.5 mm plug leaves RX or ground floating and produces exactly this kind of noise. To rule out the jack, use the DEBUG header with any 3.3 V UART adapter instead: pin 1 GND, pin 4 TX, pin 5 RX. 4. Check the image. The firmware Makefile defaults to BOARD=qmod, which assumes a 12 MHz crystal, so on SIMtrace2 hardware its UART comes up at the wrong baud. Build with make BOARD=simtrace APP=trace, and make sure any official image you flash starts with simtrace-. If all four pass and you still get garbage: 5. Rule out the clock. If lsusb shows 1d50:60e3 and simtrace2-sniff runs, the clock is fine. USB’s 48 MHz and the UART clock come from the same crystal, and USB would not enumerate on a bad one. 6. That leaves a link that is marginal at 921600. Drop the console to 115200, which divides exactly from the same clock (divisor 32), and rebuild: sed -i ‘s/^#define CONSOLE_BAUDRATE.*/#define CONSOLE_BAUDRATE 115200/’ libboard/common/include/board_common.h make BOARD=simtrace APP=trace dfu-util -d 1d50:60e3 -c 1 -a 1 -R -D bin/simtrace-trace-dfu.bin stty -F /dev/ttyUSB0 115200 raw -echo; cat /dev/ttyUSB0 make log hardcodes 921600, so don’t use it after this change.