Ultrasonic sensor, serial communication.

[louislouis]

Hi Folks,
I need a little help with this task. I want to read data from Ultrasonic distance meter which put out every 100ms serial data.
The protocol is here:
8945
The captured data looks like:
8946
My program trying to capture this data looks like:


#CONFIG
__config _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_OFF & _CP_OFF & _CPD_OFF & _BOREN_ON & _CLKOUTEN_OFF & _IESO_ON & _FCMEN_ON
__config _CONFIG2, _WRT_OFF & _PLLEN_ON & _STVREN_ON & _BORV_19 & _LVP_OFF
#ENDCONFIG

;MCU PIC 12F1840

DEFINE OSC 4 ; Use internal clock 4MHz
OSCCON = %01101010 ; 4 MHz internal
OSCTUNE = %00000000 ; Internal osc tunning

TRISA = %100000 ; RA.5 input rest output
ANSELA = %00000
OPTION_REG.7=1 ; disable internal pull-ups
APFCON = %10001100

string var byte[16]

' Set receive register to receiver enabled
DEFINE HSER_RCSTA 90h
' Set transmit register to transmitter enabled
DEFINE HSER_TXSTA 24h
DEFINE HSER_BAUD 9600

clear

start:

hSerin 100,start,[wait ($ff),str string\16]

pause 100

HSEROUT [hex string,13,10]

pause 500

goto start

obviously it doesn't work because my poor programming skills.
I searched the forum to find something to point me how to capture these data but no success.
Can someone point me how to do that?
Thanks,
Louis

[HenrikOlsson]

Try something like:

Distance VAR WORD
Sum VAR BYTE

Start:
HSERIN 1000, NoData, [wait ($FF), Distance.BYTE1, Distance.BYTE0, SUM]
' Here you could evalute SUM to verify packet is correct but lets not do that now.
HSEROUT["Distance: ", DEC Distance, "mm", 13]
Goto Start


NoData:
HSEROUT["No data from sensor", 13]
Goto Start

/Henrik.

[louislouis]

Thanks Henrik,

It works.

How simple and elegant solution.