Hi Joe,
I tried with the pullup resistor on the SCL lines, but still couldnt
get any response on the Cyclops side. I then viewed the i2c clock and
data signals on an oscilloscope once with the tmote connected to the
cyclops and then with a micaz. The signals appear totally different in
the two cases. (Waveform photos:
http://www.flickr.com/photos/[EMAIL PROTECTED]/ )
In case of the micaz, the data lines are pulled high after the write
is completed (address of device + data written to the bus) whereas in
case of the tmote the clock lines are high and the data lines remain
low after the first byte and nothing else seems to be transmitted. On
the tmote, the leds toggle indicating a write and writeDone event but
the oscilliscope shows no change on either lines till the mote is
reset.
From the I2C specification description, it says that slave holds the
clock lines low to force the master into a wait state. In my case, the
slave device does not try to force a wait state but doesnt allow a
transfer to continue as well.
I am pasting code snippets for the micaz, tmote and cyclops programs
in the space below. In the program, I used different interfaces for
the micaz and tmote but I use the same set of parameters (slave
address, data) in both cases. I am puzzled by this behavior and would
deeply appreciate any further help in this matter.
thanks,
ankur.
FOR MICAZ:
In Configuration file:
MoteI2CRelayM.I2CPacket -> I2CPacketC.I2CPacket[0x80];
In Implementation
call I2CPacket.writePacket(2,(char *)imgData, 0x00);
FOR TMOTE:
In configuration file;
SimpleResponderM.I2CPacketMaster -> I2CPacketC.MSP430I2CPacket;
SimpleResponderM.I2CStdControl -> I2CPacketC.StdControl;
SimpleResponderM.ResourceCmd -> I2CResourceC;
in implementation file:
interface MSP430I2CPacket as I2CPacketMaster;
// when user button is pressed, call task
task void getImageTask() {
imgData[0] = imgResolution;
imgData[1] = SEGMENTSIZE;
atomic {i2c_task = GET_IMAGE_TASK;}
call ResourceCmd.request( RESOURCE_NONE );
}
// After the resource is granted
event void ResourceCmd.granted(uint8_t rh) {
imgData[0] = 64;
imgData[1] = 64;
call I2CPacketMaster.writePacket(rh, i2c_slave_addr, 2, (char*) (imgData));
call ResourceCmd.release();
}
event void I2CPacketMaster.writePacketDone(uint16_t addr, uint8_t
length, uint8_t* data, result_t success) {
if (!success) {
call Leds.redToggle();
}
else {
call Leds.greenToggle();
}
}
CYCLOPS:
In Implementation file:
event char *I2CPacketSlave.write(char *data, uint8_t len) {
call Leds.redToggle();
return data;
}
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