Ez-Link on Linux - Can't Change Baud Rate

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AdamCDunlap
 
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Ez-Link on Linux - Can't Change Baud Rate

Post by AdamCDunlap »

I can't get the bluefruit ez-link to communicate at speeds other than 9600 baud when connecting to it from linux. My setup is the ez link is talking to a USB-serial converter which is connected to one computer and the other computer is connected to the bluetooth module. Using GNU screen, I can send and receive perfectly when asking them to go at 9600 baud (on one computer, screen /dev/ttyUSB0 9600 and the other screen /dev/rfcomm0 9600) but when I change to either 115200 or 19200 on both computers it doesn't work --- at 115200, nothing is displayed, and at 19200 arbitrary non-ASCII characters are displayed (going both ways). When I set the computer connected to bluetooth to use 19200 baud and the one connected to the USB-serial bridge to use 9600 baud, it works fine as well.

I've tried this on two computers. One is a laptop (thinkpad T430s, about 1 year old) with builtin bluetooth, which is reported to be version 4.0. The laptop is running Arch Linux and I'm connecting using blueman-manger and rfcomm. The other computer is a desktop running Ubuntu 12.04, with a USB bluetooth adapter which reports using bluetooth 2.1. I'm connecting using ubuntu's builtin bluetooth and rfcomm.

What I'm ultimately trying to do is to have a sensor that communicates via serial at baud rate 115200 send its sensor data wirelessly to a computer. Bluetooth is a good platform because the robot that this sensor is on also has another bluetooth-serial bridge for controlling the other functions. So I don't really need a bluetooth module that auto-detects baud rate, but just sticks at 115200. If I can make this module work, we'll probably buy 10 of them.

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adafruit_support_rick
 
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Re: Ez-Link on Linux - Can't Change Baud Rate

Post by adafruit_support_rick »

We have seen this before, and it turned out to be a problem with the BT adapter on the computer. We have tested this BT adapter, and it works:
https://www.adafruit.com/product/1327

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