I wrote a snippet of code that:

1. set the 'range' registers, rangeright and rangefront, each to 1
2. gosub blinkloop01 if the 'range' registers are both 1
3. do the pulsout, pulsin exercise
4. gosub blinkloop45 and blinkloop67 if the range registers are 0

I ran the code. The LED's told me that pulsin is loading the range registers with 0. Why??

---------start code-----------
symbol trigright = PORTB.0 ' Define output pin for Trigger pulse
symbol trigfront = PORTB.1 ' Define output pin for Trigger pulse

symbol echoright = PORTB.2 ' Define input pin for Echo pulse
symbol echofront = PORTB.3 ' Define input pin for Echo pulse

rangeright var word
rangefront var word
rangeright = 1
rangefront = 1

if rangeright = 1 and rangefront = 1 then
gosub blinkloop01
endif

main:

DEFINE PULSIN_MAX 65535
pulsout trigright,2
pulsin echoright,1,rangeright

pulsout trigfront,2
pulsin echofront,1,rangefront
pause 10 ' recharge period after ranging completes

'*****test for zeros******
IF rangeright = 0 then
gosub blinkloop45
endif
if rangefront = 0 then
gosub blinkloop67
endif
goto main:

------------end code----------