also 100 iterations of this has every chance of overflowing a word var
z = tc + z
ie 100*921 = 92100 , word max val 65535



every count of tc = 5000/1024 mv


40 deg = 4500 mv would be a 921 count


the most accurate calc for pbp

would be mvolt = tc */ 1249

result for 921 = 4493



ps I assume ADFM set correctly