While troubleshooting an old but extremely robust threadmill, I came across an RS-232 data link between the device and its master computer. Since I do not have any instruments to sniff the messages flowing through a RS-232 link, I decided to build an extension board to add this capability to my Analog Discovery II instrument (AD). To give myself more flexibility, I am adding plenty of headers to monitor extra signal lines in addition to the main RxD and TxD. A total of five lines can be monitored at any time.
Use it at your own risk. I take no responsibility for any damage caused to any device attached to this board. Since this is an experimental circuit, I assume that whoever is reading this is a tinker and has basic skills dealing with extra-low-voltage circuits.
- Uses the Texas Instrument TRSF3243EIPWR Multichannel RS-232 compatible line driver/receiver
- Five channel RS-232 sniffer
- Passthrough DB9 Male to DB9 female
- RxD and TxD lines always connected to AD instrument
DIO[0:1] - Selectable signals can be connected to the AD
DIO[2:4]via header shunt pins - RxD and TxD signals connected to AD instrument oscilloscope channels
- Optionally, RxD and TxD can be driven by an AD instrument using
DIO[8:9] - It is also possible to select one more signal line to be driven by an AD instrument
DIO[10] - The driver power can be enable(disable) driving the
DIO[15]high(low)
- A data link with RS-232 communication to sniff on
- Personal Computer
- Digilent Analog Discovery (R) Instrument
- Software Digilent Waveforms(R)
- Some extra db9 terminated cables to make the connections
Analog Discovery (R) and Waveforms(R) are Digilent trademarks. The license is described in the file 'LICENSE'.