Making MaxMSP talk to sparkfun bitwhacker

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Making MaxMSP talk to sparkfun bitwacker

Items needed:

1. Bitwacker board (


2. Usb cable

3. Boot Down Application
4. uosc -1.04 folder

Please visit to obtain the required files.

Double click on the Boot Down Application to open it.
Open the uosc-1.04 /hex/Which Firmware To Use.txt  for instructions in programming the bitwacker device.
Follow the instructions. For this device the recommended HEX file is uOSC-1.04 PIC18F2455BITWACKERTTL_PORTBINT.hex

After following these steps,  quit out of the Boot Down application.  See if MaxMSP talks to the bitwacker  by connecting it to the computer via the usb cable.  Then open uosc-1.04 /max/display/uosc.display-bitwacker.mxb in MaxMSP.  

There is a corresponding MaxMSP interface to the board. In other words, the '/ra/#'  and '/rb/#' in MaxMSP correspond to the 'RA' and 'RB' columns on the board respectively.  To make any '/rb/#' patch an output, use the drop down menu within the '/rb/#' patch and select 'output'.  Then press command E and connect the the outlet of this patch to the inlet of the '' object.  Press command E again and the toggle switch should be able to turn the corresponding outlet on and off.

Screen shot 2009-11-26 at 2.55.37 PM.png 

To convert the input interfaces to output interfaces like above, press command E.  Copy and paste a '/rb/#' output patch for duplication and press command I for the Inspector and edit the Arguments row to provide the correct new name for switching the corresponding outlet on and off.

1 Comment


Thanks for the instructions
I checked in with the developers of uosc at UC Berkeley's CNMAT.
A few clarifications/updates to quote from Andy Schmeder (uosc developer):

-Regarding analog inputs and the weird wrapping around problem we noticed in class with Andy: "The wrapping around is probably because you have one of the new bitwackers with the PIC18F2553 processor. These have a 12-bit converter so if you run the 18F2455 firmware on them you will get weird results. All of the new ones are the 12-bit now. ... I need to release the 2553 .HEX files onto the website so you can get those working properly...". Andy has promised to provide me with the current 2553 hex files so that we can move forward. in the mean time, analog inputs 0 and 5 (i.e. /ra/0 and /ra/5) work fine.

-regarding /ra/4: Andy and i noticed that we weren't getting any analog readings from that pin. as it turns out: "ra/4 has a special function in the hardware" and is therefore not usable as an analog input pin.

i'll post updates as i receive them from the left coast.


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This page contains a single entry by vasu0002 published on December 4, 2009 3:15 PM.

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