'PICAXE-20M,7 seg LED & DS18B20 demo. Stan.SWAN + PICAXE "Forum" 3 May 2008
'Uses single 7 seg display,sequencing digits so 24°C temp="2" then "4" etc
'Ranges very cold subzero (preceeded with flashing -ve) to ~99°C within ½°C 
'Suits further tweaking for info.display needs or enhanced battery life etc
'204/256 bytes.Much tighter programming possible- EEPROM,symbol etc 
'Program download at => www.picaxe.orconhosting.net.nz/20m7segds.bas
'Schematic download  => www.picaxe.orconhosting.net.nz/20m7segds.gif
'Breadboard layout   => www.picaxe.orconhosting.net.nz/20m7segds.jpg
'---------------------------------------------------------------------------
temp20m:readtemp 7,b0    'DS18B20 temp reading at 20M input 7
if b0>128 then gosub negtemps 'Sub zero temps value correction

b1= b0/10		 'divide orig temp to get tens value
b2= b0//10		 'divide orig temp so remainder yields units value
if b1=0 then units 	 'suppress "0" if temps between ±9°C,so "4" & not "04"
                          
tens:                	 'tens numeral test,with first digit suppressed if 0
on b1 gosub zero,one,two,three,four,five,six,seven,eight,nine 
wait 1:pins=%00000000 	 'blanks all 7 segs to ensure tens & units 
pause 200                'don't run together if similar- 11,22,33 etc

units:			 'units numeral test
on b2 gosub zero,one,two,three,four,five,six,seven,eight,nine
wait 2                   'units digit extra hold on,as likely of most interest
pins=%00000000:wait 1    'blanks for DP heartbeat between each temp.display 
for b3 = 1 to 3:pins=%00000001:wait 1:pins=%00000000:wait 1:next b3
goto temp20m             

'Bit order follows 20M outputs 7,6,5,4,3,2,1,0 (or 7 seg g,f,e,d,c,b,a,+DP)
'if wired as on 20M breadboard demo using DSE Z4104 7 seg LED
 zero: pins=%01111110:return '0 shows
 one:  pins=%01100000:return '1 shows
 two:  pins=%10110110:return '2 shows
 three:pins=%10011110:return '3 shows
 four: pins=%11001100:return '4 shows
 five: pins=%11011010:return '5 shows
 six:  pins=%11111010:return '6 shows
 seven:pins=%00001110:return '7 shows
 eight:pins=%11111110:return '8 shows
 nine: pins=%11001110:return '9 shows

negtemps:'DS18B20 subzero negative temps routine + flashing -ve alert
for b3 = 1 to 2:pins=%10000000:pause 200:pins=%00000000:pause 200:next b3
b0 = b0 - 127:return 'b0 now correctly able to show subzero temps