Using GMECMEdit on an 86 TPI bin ($32) and 32bv001.ecu, I have a question about the flags that can turn on and off. The VATS, MAF, EGR fields are easy enough to know what's going on (checked on, blank off)... but what are the "b0, b1, b2, etc" values that come up?

 

These are "default" labels for each field. They stand for bit 1, bit 2, etc ... If they are unlabeled like this, it means the person who created the ECU file didn't really know what they were for, or they are unimportant. You can consult a hac of the bin to find out what they're for (if known).

The way a flag (or "bitmask" as they're actually called) works is this:

you have a single byte (in the case of our 3rdgens). 1 byte = 8 bits (eg 10010101).

This means you have 8 "flags" per byte. the 0th bit is all the way to the right, the 7th bit is all the way to the left. when a flag is checked, the bit in the corresponding position within the byte is set to 1. unchecked, the bit is 0.

so 0x00 (binary 00000000) would have no flags checked. 0x01 would have the 0th bit checked (00000001), and 0xFF would have all bits checked (11111111). Hope this helps.

M

 

A good rule of thumb is, if you don't know what it's for, you shouldn't touch it. You might accidentally hit the 'war games' bit and your ECM might unleash global thermonuclear war instead of running the car.

 

or, if you have an extra powerful ECM, it might launch global thermonuclear war WHILE running the car.

 

Would you like to play a game?

Thanks guys. That was an easy one, being in binary relates directly to my job in the telecom field. Now, to move on to burn number two...