PBP projects for R/C models

[Kenjones1935]

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----------

[Kenjones1935]

Maybe a PICBASIC robotics forum would know what is wrong with my PULSIN. They are always dealing with sensors.

Suggestions?

Ken

[Kenjones1935]

Channel 2 is PULSOUT.
Channel 3 is the corresponding PULSIN.

PULSOUT is waaayyy to long. It is supposed to be 20 microseconds since I am using the 4meg oscillator and my command is

PULSOUT trigfront 2

PULSOUT is about 14 millisec according to the LOGIC TOOL. See picture. Oops. The forum won't honor my request to upload the picture. You'll have to take my word for it.

Any ideas?

[Kenjones1935]

I chose, by flipping a coin, to have my PULSIN inputs on pins PORTB.2 and PORTB.3.

Is it possible that these pins can not accept pulses for width measurement? I read a two year old posting that seemed to say by changing his PULSIN pins from PORTA to PORTC everything suddenly worked. He was having the same problem as I. The pulse is on the pin, but the PIC does not act upon it.

KEn

[Archangel]

Hi Ken, Are you still using 16F887. If so PortB is lousy with analog functions, just waiting to be disabled.

[Kenjones1935]

Joe,

Are you saying that all I need to do to use PORTB is figure out how to appropriately configure it?

If so, please give me a hint? I am soooo close.

Ken

[Archangel]

Joe,

Are you saying that all I need to do to use PORTB is figure out how to appropriately configure it?

If so, please give me a hint? I am soooo close.

Ken

Ken,
I am not an expert on pulseout or pulsein, and I have not read the manual lately, but I believe they are digital commands, which by default should require you to disable the analog functions on the pin you are using.
On this chip you have,
ADCON0
ADCON1
ANSEL
ANSELH
CMCON0
CCP1CON
CCP2CON
CM1CON0
CM2CON0
CM2CON1 and a couple more which all have effect on the I/O. Get into the data sheet and read about them, they are all listed in the index of the data sheet, and see how to set them up. Remember if a bit is SET it is a 1 if cleared it is a 0.
When you come out of the data sheet you will be a much more "Savy" programmer.