Over the last couple of nights I’ve been verifying the respective individual circuits of Rallylog before I get down to developing the application.
Test Results so far:
|LCD Back Light||PASS|
|SD Card||FAIL (Fixed)|
|SD Card Detect||PASS|
|Battery Voltage Monitor||PASS|
|USB – FTDI||PASS|
|USB – AVR (Serial)||FAIL|
I’ve had a couple of problems so far, first the RFID module has very short pins that only just go through the PCB to allow for soldering, I had what looked to be a dry joint on one of the pins, after re-soldering with a bit more heat and solder all joints now are solid and is working no problems. The Range of the card read seems to be far less than specified, so I’m wondering if the GND fills on both sides of the PCB near the RFID module could be causing this, I will remove them in the next PCB iteration. However it is working and the range is sufficient to work as required.
I now have writing to the SD card working, had an initial problem where the pull-up resistors were causing the problem, removed and now ok. I’m using the filelogger library (http://code.google.com/p/arduino-filelogger/) and have it writing the test message to the card. A gotcha was an existing 1-Byte sized file needs to already exist on the SD card for the library to work. I’m also having some problems when the card is removed and re-inserted no writing takes place. This appears to be a library problem so will investigate further later.
Another problem is the USB side of things. I’m using an FTDI FT232RL USB-Serial conversion chip, fairly common, however the output on my Tx is garbled, I’m also assuming that my Rx is the same as I have yet to delve deeper into the problem. It may be an unidentified solder bridge somewhere that I can’t see, the pitch on this component is pretty fine.
I’ve checked correct bit rates but still failing. I initially found I had problems when I went to program the bootloader and could not get any of them to work, so have filed this as a FAIL and moved on to complete the rest of the testing as I’m using the programmer interface to load my test sketches. I’ll revist in detail later.
UPDATE: I have downloaded the FTDI chip programmer utility and this sees the FTDI chip and alls it’s registers ok, so the USB-FTDI circuit appears to be working, but the FTDI – AVR is not.
- #Rallylog Fusebits
- Putting the Project into an Enclosure–Part 2 Machining the Case
- Putting the Project into an Enclosure – Part 1
- My Move to Kicad
- New Tool for PCB inspections