I'm using a known good FTDI USB -> UART bridge to talk to a 3rd part module on my board. I've just assembled the board, and it's not impossible that I fried a component in the process (it's what I'm trying to understand right now)
When I send data through the UART, I get this:
The yellow is the incoming TX (RX from the module's perspective) line and the blue is the RX. As you can see, data is coming in fine, but it's causing this weird "echo" effect on the module's TX pin, with no response from the module (I'd expect something back).
The module is a Bluetooth module I've worked with before, connected like this:
(the TX and RX lines are flipped appropriately on the FTDI connection)
Any ideas what this is? Is it just a fried module?
Best Answer
The serial BT module can be checked easily without any tools. Short TX to RX then pair the module with a phone, PC, etc., open a terminal and type something. If module is working you'll get echo back. Make sure 'local echo' is turned off in the terminal. If you have known good module practice on it first.
FTDI USB to serial can be tested using the same technique.