Compass module and I2C bus

[mister_e]

what happened to your results when you change to a Byte Sized variable? you should read something between 0-255

NOW if you want to use a word sized variable, YOU MUST READ register #2, not 1, so try...

ControlByte VAR BYTE
Register VAR BYTE
ControlByte = $C0
Register = 2
'
'
'
'
i2cread dpin,cpin,ControlByte,Register,[bearing.highbyte, bearing.lowbyte]

and you should read something in a range of 0-3599
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=1249&stc=1&d=116582183 1">

About now?

[vladimir059@hot]

Big Thank You Mister E.
You and MELABs staff helped me to find mistake. I insert in my code two lines and now program works great. These are two lines:
DEFINE I2C_HOLD 1
DEFINE I2C_SLOW 1

Maybe, someone will have the same problems in future, so I decided to post all my code. It works flawless.
Thanks again
Vladimir

'PIC16f872
'---------------- Definitions---------------------------------------------
define OSC 20
'------------- Define LCD registers and bits------------------------------
DEFINE I2C_HOLD 1
define I2C_SLOW 1
Define LCD_DREG PORTB 'Set LCD data port
Define LCD_DBIT 0 'Set starting data bit
Define LCD_RSREG PORTB 'Set LCD register select port
Define LCD_RSBIT 4 'Set LCD register select bit
Define LCD_EREG PORTB 'Set LCD enable port
Define LCD_EBIT 5 'Set LCD enable bit
define DEBUG_REG PORTC 'Set DEBUD port
DEFINE DEBUG_BIT 1 'Set DEBUG pin
DEFINE DEBUG_BAUD 2400 'Set DEBUG baud rate
DEFINE DEBUG_MODE 0 'Set DEBUG mode



DPIN var PORTc.4 ' I2C data pin
CPIN var PORTc.3 ' I2C clock pin
bearing var word ' word size bearing value 0 - 359
bearing1 var byte ' byte size bearing value 0 - 255

Main:
i2cread dpin,cpin,%11000000,2,[bearing.Highbyte,bearing.lowbyte]

lcdout $fe, 1,"BEARING ",DEC BEARING/10

i2cread dpin,cpin,%11000000,1,[bearing1]

lcdout $fe, $c0,"Bearing ", dec bearing1

DEBUG " Compass Bearing ", # bearing,13,10

pause 20

goto main

[mister_e]

Nice!

Now forward the info to Devantech

[vladimir059@hot]

DONE. I mailed Info to Devantech.
Best Wishes.
Vlad

[shaiqbashir]

Hi guys!

Well ! i have some confusions in understanding the following program :

1) what is the purpose and function of this line :

DEBUG " Compass Bearing ", # bearing,13,10

2) Why is the address be written as %11000000?

3) WHat is the function of this line:

i2cread dpin,cpin,%11000000,2,[bearing.Highbyte,bearing.lowbyte]

4) and what this DEC sign means, i have checked the help section, it is no command. Then why it is written there :

lcdout $fe, 1,"BEARING ",DEC BEARING/10


lcdout $fe, $c0,"Bearing ", dec bearing1

Please help me as soon as possible!

and can anyone tell me whats the cost of this CMPS-03?

Can we operate it through I2C on PIC16F84A?

[vladimir059@hot]

Hello shaiqbashir!

I will try to give you answers.
1) what is the purpose and function of this line :
DEBUG " Compass Bearing ", # bearing,13,10

This is optional line, for development purposes only. It is sends “bearing” value serially to a terminal. In my program this command sends serial string to PORT_C, pin No1, baud rate 2400.

2) Why is the address be written as %11000000?

This is address designated by Devantech (Devantech is company producing the compass module)

3) WHat is the function of this line:

i2cread dpin,cpin,%11000000,2,[bearing.Highbyte,bearing.lowbyte]
Function of this line is reading "bearing" value through I2C bus, as WORD size variable.


4) and what this DEC sign means, i have checked the help section, it is no command. Then why it is written there :

lcdout $fe, 1,"BEARING ",DEC BEARING/10
lcdout $fe, $c0,"Bearing ", dec bearing1

DEC means decimal. This is not command, this is modifier, it is similar to # sign and gives ASCII representation of value sending to LCD.

and can anyone tell me whats the cost of this CMPS-03?

http://www.robotshop.ca/home/product...le-cmps03.html

Can we operate it through I2C on PIC16F84A?

Why not? In my application I use PIC 16F872 because 16F84A has limited amount of ports (pins).
Best regards Vlad

[shaiqbashir]

Many Many Thanks Mr. Vladimir

please tell me the following two points as well!

1) Which type of LCD screen have u used. Can i use an LCD screen with three terminals (+5V, GND, control) using Serout command? What lcd u have used?

2) On each PIC, it is usually written that which is the SDA pin and which is the SLA one. While when i was reading the diagram of PIC16F84A , it was not mentioned. According to you , i can use this I2C on PIC16F84A, is it possible that we can use any two pins for I2C operation? or are there always two fixed pins dedicated for it?

I shall be looking for ur precious reply!

Take carez!

Good Bye!