PIC24HJ64GP502 mini-Bully

[Bryan Bennett]

I am using 2 separate PIC24HJ64GP502 mini-Bullies: one on a breadboard circuit where I test new algorithms and the other on a prototype that connects to my wrist to monitor and record heart rate data while I sleep so as to try to detect REM periods (Rapid Eye Movement, when dreams occur). Both PIC24s are using the Bully Bootloader with the MPLAB IDE v8.70 on my laptop. I have not used the prototype PIC24 in about a year. When I previously did use the prototype PIC24, an engineer friend of mine (Cliff, who is much more experienced than myself but presently unavailable) installed the Tera Term logging program on my laptop to log the sleeping heart rate data since he could not determine how to activate the Bully Bootloader logging program (selecting "Logging Enabled" in Bully Bootloader window did not work). In order to use the Tera Term program, Cliff had to open the the SJ3 junction on the mini-Bully circuit board (on the prototype PIC24, not the breadboard PIC24) and thus disconnect its reset pin (MCLR pin #1) from its JP1 RST pin (green wire on USB connection to laptop)

After a year of learning how to write and test new algorithms on my breadboard PIC24, I again returned to my prototype PIC24 to install and use these algorithms while wearing the prototype during sleep. The SJ3 junction on the mini-Bully circuit board was reconnected on the prototype PIC24 since I did not intend to use the Tera Term logging program again but rather only the Bully Bootloader window to view the changing values of my program variables (as I had done on my breadboard PIC24). I had written an algorithm for my I2C accelerometer (MMA8452Q from Spark Fun) that worked perfectly fine on my breadboard PIC24 but failed to work on my prototype PIC24. As I went back and forth between using my two different PIC24s on the Bully Bootloader while trying to get this accelerometer algorithm to work on the prototype PIC24 as it did on the breadboard PIC24, I eventually got to a point where the prototype PIC24 would not even connect to the Bully Bootloader. The Bully Bootloader read: "Exception during serial port read: the operation has timed out. Unable to connect to device, giving up."

After thinking about this for some time, here is my question (and I apologize for my ignorance concerning how these microcontroller devices work; I still have much to learn): when Cliff installed the Tera Term logging program on my laptop, did some Tera Term code also get installed on my prototype PIC24, and could that Tera Term code be interfering with the Bully Bootlaoder code which I also assume is installed on my PIC24? If so, should I try to download new Bully Bootloader code on my prototype PIC24 and thus overwrite the Tera Term code? Any advice that you could offer would be greatly appreciated since I would really like to be able to use my prototype PIC24 again. Unfortunately, Spark Fun no longer sells the PIC24HJ64GP502 mini-Bully.