AB Micrologix 1500 String ASCII convert to Bits

Hello,

I am a veteran Mitsubishi programmer, but am new to AB. I have a Micrologix 1500. I am receiving a string via RS232 on Channel 1. In that string there is a character that is a response character to a command. Each bit in that character means something. i.e. bit 0=error, bit 1=busy, bit 2=bad command etc.

My question is, how to I take a single character and get bit values out of it? I tried ACI instruction but since it is not a number, this fails. Then I tried MOV ST10:0.DATA[1] N7:0 and then accessed the bits via N7:0/1 but this didn't seem to work either. Am I missing something?

Thanks for any help.

ST10:0.DATA[1]

Click to expand...

So the character is the second character in the string?

Can you provide an example of a typical response string as seen in ST10:0?

Each character in your string is a byte, so there are two characters per 16 bit word. The ACI will convert an ascii character to an integer, and is only useful if the character is numeric...not what you want...

If you COPy the ST data to integer(s), it will not perform any conversion, and the bit pattern should remain intact. Note that the length parameter of the COP instruction is in reference to the number of elements of the destination. If your destination is an N file or B file, each element is 16 bits, so you'll be copying 2 characters into each element, since each character is only 8 bits in the source.

Bernie - you got me most of the way there. I had made a bad assumption that the array would start at 1 because when I had tried to get other characters out of a string, the array is 1 to 82. So my "MOV ST10:0.DATA[1] N7:0" became "MOV ST10:0.DATA[0] N7:0".

Then I had to do an SWP because the two bytes were reversed, my bit I was looking for was in the upper byte of the integer. I suppose I could have just displaced my lookup from bit 5 to bit 13 but that would be confusing later on when reading documentation from the vendor of the other device.

Thanks for the FAST response.