Sping Stamp and I2c / SRF02 problems
raptor313
Posts: 4
I'm using an SRF02 with a Spin Stamp. I've run into a problem. Until yesterday I had the thing working. After a very long time trying to debug it. Well yesterday I went to open up the file only to find an Optimal configuration within brackets and a list of Windows Drivers. I can't for the life of me get the SRF02 sensors to work. I know they're still working as I tested them with my Basic Stamp code and they work just fine. Could someone with some more experience take a look at this and tell me whats going on. I've downloaded this code from
SRF02.spin
this is the modified SRF02 code I got from http://www.robot-electronics.co.uk/files/i2cObject.spin
SRF02.spin
con
_clkfreq = 10_000_000
_CLKMODE = xtal1 + pll8x
i2cSCLLine = 9 'SCL is on Proppeller pin A13
i2cSDALine = 8 'SDA is on Proppeller pin A12
SRF08_addr = $e0 'SRF08 default address
SRF08_CMD_REG = 0
SRF08_VER_REG = 0
SRF08_LDR_REG = 1
SRF08_ECHO1H_REG = 2
SRF08_ECHO1L_REG = 3
PING_CM = 81
OBJ
i2cObject : "i2cObject" 'include the I2C handler
Num : "numbers" 'number handler allows number (keypad states) to easily be formated to ascii text string
'note numbers is an object file included in installation directory
var
byte version,length,light
word range
pub main
Num.init 'required by parallax to be called before using Num.ToStr function
i2cObject.init(i2cSDALine,i2cSCLLine) 'passes the pin numbers of the sda and scl lines to i2cobject
repeat
i2cObject.Writelocation(SRF08_Addr,SRF08_CMD_REG,PING_CM) 'command to commence a range 'ping'
waitcnt(6_000_000 + cnt) 'delay for ranging
version := i2cObject.readLocation(SRF08_addr,SRF08_VER_REG) 'SRF08 version in register 0
range := i2cObject.readLocation(SRF08_addr,SRF08_ECHO1L_REG) 'low byte of first echo at reg 3
range += i2cObject.readLocation(SRF08_addr,SRF08_ECHO1H_REG)<<8 'High byte of first echo at reg 2
this is the modified SRF02 code I got from http://www.robot-electronics.co.uk/files/i2cObject.spin
'' ******************************************************************************
'' * Simplified I2C for Devantech modules *
'' * Chris Clarke Feb 2007 *
'' ******************************************************************************
''
'' adapted from I2C SPIN Object by James Burrows
''
'' for reference look at: www.semiconductors.philips.com/ acrobat/literature/9398/39340011.pdf
''
'' this object provides the PUBLIC functions:
'' -> Init - sets up the SCL and SDA pin referance
'' -> readLocation - READ from a single specified register
'' -> writeLocation - WRITE to a single specified register
'' -> i2cStart - performs a bus start
'' -> i2cStop - performs a bus stop
'' -> i2cRead - performs a read of the i2c bus
'' -> i2cWrite - performs a write to the i2c bus
CON
' i2c bus contants
_i2cNAK = 1
_i2cACK = 0
VAR
byte i2cSDA, i2cSCL
PUB init(_i2cSDA, _i2cSCL)
i2cSDA := _i2cSDA 'referances passed from main file for pin numbers
i2cSCL := _i2cSCL
outa[noparse][[/noparse]i2cSDA] := 0 'as inputs to start
outa[noparse][[/noparse]i2cSCL] := 0
PUB readLocation(deviceAddress, deviceRegister) : i2cData | ackbit
' do a standard i2c address, then read
' read a device's register
ackbit := _i2cACK
i2cStart
ackbit := (ackbit << 1) | i2cWrite(deviceAddress)
ackbit := (ackbit << 1) | i2cWrite(deviceRegister)
i2cStart
ackbit := (ackbit << 1) | i2cWrite(deviceAddress | 1) ' repeat with read bit now set
i2cData := i2cRead(_i2cNAK)
i2cStop
' return the data
return i2cData
PUB writeLocation(deviceAddress, deviceRegister, i2cDataValue) : ackbit
' do a standard i2c address, then write
' return the ACK bit from the device address
ackbit := _i2cACK
i2cstart
ackbit := (ackbit << 1) | i2cWrite(deviceAddress)
ackbit := (ackbit << 1) | i2cWrite(deviceRegister)
ackbit := (ackbit << 1) | i2cWrite(i2cDataValue)
i2cStop
return ackbit
PUB i2cStop
' i2c stop sequence - the SDA goes LOW to HIGH while SCL is HIGH
dira[noparse][[/noparse]i2cSCL] ~
dira[noparse][[/noparse]i2cSDA] ~
PUB i2cStart
dira[noparse][[/noparse]i2cSDA] ~
dira[noparse][[/noparse]i2cSCL] ~
dira[noparse][[/noparse]i2cSDA] ~~
repeat until ina[noparse][[/noparse]i2cSCL] == 1
PUB i2cWrite(i2cData) : ackbit
i2cData <<=24
' init the clock line
dira[noparse][[/noparse]i2cSCL] := 1
repeat 8
' set the SDA while the SCL is LOW
dira[noparse][[/noparse]i2cSDA] := (!(i2cData <-= 1) & 1)
' toggle SCL HIGH
dira[noparse][[/noparse]i2cSCL] := 0
' toogle SCL LOW
dira[noparse][[/noparse]i2cSCL] := 1
' setup for ACK - pin to input'
dira[noparse][[/noparse]i2cSDA] := 0
' read in the ACK
dira[noparse][[/noparse]i2cSCL] := 0
ackbit := ina[noparse][[/noparse]i2cSDA]
dira[noparse][[/noparse]i2cSCL] := 1
' leave the SDA pin LOW
dira[noparse][[/noparse]i2cSDA] := 1
return ackbit
PUB i2cRead(ackbit): i2cData
' set the SCL to output and the SDA to input
dira[noparse][[/noparse]i2cSDA] := 0
dira[noparse][[/noparse]i2cSCL] := 1
' clock in the byte
i2cData := 0
repeat 8
dira[noparse][[/noparse]i2cSCL] := 0
i2cData := (i2cData << 1) | ina[noparse][[/noparse]i2cSDA]
dira[noparse][[/noparse]i2cSCL] := 1
' send the ACK or NAK
dira[noparse][[/noparse]i2cSDA] ~~
dira[noparse][[/noparse]i2cSCL] := 0
dira[noparse][[/noparse]i2cSDA] := !ackbit
dira[noparse][[/noparse]i2cSCL] := 1
' return the data
return i2cData
Comments
Have you looked at my updated i2cObject (v2.1 currently) in the object exchange?··obex.parallax.com - its also available on the http://www.robot-electronics.co.uk/acatalog/examples.html examples page.
It has working demo code for the SRF08 and many other i2c devices from Davantech.
Couple of spots on a quick check:
Shouldn't this be:
??· What crystal are you running with?
and;
the comments don't match the pins?
Let us know how you get on.
Cheers,
James
@raptor: You can also try my I2C routines, but tested with PCF chips only... Though they look very similar
J
but ther estill seems to be something wrong. I'll post it up later, I'm trying to see if its an electrical issue right now, although it seems strange that it works just fine on the
BASIC stamp on the same BOE-bot board.
Good news
james