Using the I2C bus

[dan1els0n]

yeah i learnt that the hard way! As i said i am new, but learning fast! so sorry for asking what might seem trivial questions!

[kurte]

@kurte

Also I discussed some stuff with the Basic Micro people and there are a few issues with the new command syntax. That is there is no provision for the commands to error out. That is it should give you an error if the device fails, (Not there or busy). I don’t think the current version has that in it.

Quick update: I now have version .16 of studio up and it again has the error label!

From Nathan

@Acidtech

The optional errorlabel still applies. If no device is found the i2c command will error out. However the catch is if the i2c device is busy it will also error our(eg jump to the error label).

i2cout dpin,cpin,ERRORLABEL,controlbyte,[data,data…]
i2cin dpin,cpin,ERRORLABEL,controlbyte,[data,data…]

where “ERRORLABEL,” is an optional label name to jump to on a failure

When it applies:
After a control byte is sent the device should send a NACK. If it does not, jump to errorlabel.
After a data byte is written to the device , the device should send a NACK. If it does not, jump to errorlabel.

When these will happen depend on the device state:
If the device is busy it will not send a NACK back after the control byte(so you know the device is busy or there is no device attached). Note that in the case no device is attached a PULLUP is still required for this to function correctly.
If writing to the device and it does not send a NACK back then you have a write error.

To use the errorlabel on an i2c eeprom then you should:

;see if device is attached
i2cout dpin,cpin,nodevice,%10100000,[address.high,address.low]
;if so try writing to it.
i2cout dpin,cpin,writeerror,%10100000,[address.high,address.low,data]
return

nodevice
serout s_out,i9600,"No Device attached"]
return

writeerror
serout s_out,i9600,"Write failed"]
return

To translate this into your SRF08 code I believe this is what you want:

SRFPing[srfAdr]

startcnt=0
retrystart:
startcnt=startcnt+1
if(startcnt>1000)then nodevice
i2cout sda,scl,retrystart,srfAdr,[SRFCmdReg,80]
srfRange = 0
pause 67

retryreceive
i2cout sda,scl,retryreceive,srfAdr,[SRFRangeReg]
i2cin SDA,SCL,srfAdr,[srfRange.HighByte,srfRange.LowByte]
return srfRange

nodevice:
    return 0

This assumes the SRF08 does not return a NACK when busy.

[dan1els0n]

hey guys.
I had the sensor working and the micro displaying the range on screen a couple of days ago. I was using a voltmeter to note down some readings across my vari-board and i think i shorted the input to the output of the regulator, and stupidly i was using my servo battery at the time to power the board (3.3A). Now i am having trouble communicating with the sensor, and at first i thought that i had blown it so i bought a replacement. I am having the same problem with this new one too! do u think that its possible i sent a power surge thru to the atom pro and blew the pins 6 + 7 (the hardware i2c)?

some older programs still work using the buttons and speaker.

is it possible to have only blown the i2c pins? do you think i need a new micro? or do you think there could be something wrong with the variboard pull up resistor configuration?

the micro is hanging as soon as an i2cin / i2cout command is used!

[km6vv]

I wouldn’t think shorting VL to ground would kill anything but the regulator, and perhaps the battery. Most likely, you have opened up a power trace. See if you have +5 going to the sensor.

Not likely to fry the I/O pins of the module. But depending on exactly where you shorted out the power, you could have lost a trace.

Alan KM6VV

@dan1els0n

hey guys.
I had the sensor working and the micro displaying the range on screen a couple of days ago. I was using a voltmeter to note down some readings across my vari-board and i think i shorted the input to the output of the regulator, and stupidly i was using my servo battery at the time to power the board (3.3A). Now i am having trouble communicating with the sensor, and at first i thought that i had blown it so i bought a replacement. I am having the same problem with this new one too! do u think that its possible i sent a power surge thru to the atom pro and blew the pins 6 + 7 (the hardware i2c)?

some older programs still work using the buttons and speaker.

is it possible to have only blown the i2c pins? do you think i need a new micro? or do you think there could be something wrong with the variboard pull up resistor configuration?

the micro is hanging as soon as an i2cin / i2cout command is used!

[dan1els0n]

I fixed it. I just made a new board with new components on the external circuitry, not sure exactly what i fried but the micro is still alive

[km6vv]

Good to hear!

Point to point wiring? Wire-Wrap? (wonder if anyone here knows what that is!).

Might want to buzz-out the power wiring just to see…

Alan KM6VV

@dan1els0n

I fixed it. I just made a new board with new components on the external circuitry, not sure exactly what i fried but the micro is still alive

[km6vv]

Any progress on this project, or on the BAP compiler for I2C and SRF08?

Alan KM6VV