I2C, picaxe, wc32 communication

Hi friends,
 
Simple question, I guess that is possible to make a communication between a picaxe such as 28x2 chip or 08m2 and my wc32 using i2c. But i never used i2c, i'm reading doc on wikipedia but it's so confusing for me. Maybe there is a simple way to understand this kind of communication..? And how to achive that.
 
 

The 08M2 device will only operate as an I2C master.
Unfortunately, the webcontrol also operates only as a master.
I looked at doing this some time ago, and the only way I could see of doing it was to use something like an external RTC+memory board as an intermdeiary, but even then there was no multi-master arbitration support on the webcontrol.
(I ended up giving up and doing my project another way).

sad news...  :blush:

08M2 only has I2C master, but higher end chips like 20x2, 28x2 and 40x2 all support I2C slave functions.

What do you want to do with 08M2?  Maybe we could add that function to WC32 and WC8.  If you consider all the cost, it is probably a lot cheaper to use WC8 than 08M2, since you have to make PCB and all the work and writing and debugging code.

I had several cases where I was going to offload to an 08M2 or 14M2.
1. Additional counters.
2. Accurate time measurement (ultrasonic ranging)
3. Serial (RS232)
 
Additionally, I was going to use the 08M2/14M2 as a watchdog, to monitor for a specific event (or a certain time elapsed) and to then turn on the power-hungry WC8 and radio node. This was for a remote monitoring site with small battery and solar. Plenty to run for a few hours but not 24/7, whereas the picaxe will run all day on a few milliwatts.

Sure, if you run it in lower power mode, it would work for waking up in certain condition.  But on few milliwatts power, it will not probably able to do counters or time measurement, or RS232.
 
We are thinking it might be worth to add a low power mode, so that only TTL input works, when certain condition met, it will jump up to full power mode to enable network.

CAI_Support said:

What do you want to do with 08M2?  Maybe we could add that function to WC32 and WC8.  If you consider all the cost, it is probably a lot cheaper to use WC8 than 08M2, since you have to make PCB and all the work and writing and debugging code.

Click to expand...

 
 
remote sensor using serial communication, radio, etc. Sharing data with other chip, arduino, picaxe, etc
 
 
If i'm right, wc8/32 are both worst thant picaxe when power cumsuption is essential. 
 

We are thinking it might be worth to add a low power mode, so that only TTL input works, when certain condition met, it will jump up to full power mode to enable network.

Click to expand...

 
 
not a bad idea....

CAI_Support said:

08M2 only has I2C master, but higher end chips like 20x2, 28x2 and 40x2 all support I2C slave functions.

Click to expand...

 
 
 
yeah i saw that today!

CAI_Support said:

Sure, if you run it in lower power mode, it would work for waking up in certain condition.  But on few milliwatts power, it will not probably able to do counters or time measurement, or RS232.

Click to expand...

 
I'm running 08M2 systems that are NOT in low-power mode, and measuring a couple of hundred microamps. Lets round it up to 1mA
At 5V, that's five milliwatts. In reality, it's taking less than that.
 
I built a temperature logger for a friend in the USA, but to be sure it was working I set it off here first (I was just sending him the code). I forgot about it, and found it later - still blinking it's LED every 15 seconds, still reading the DS18B20 probe, still logging... after 4 MONTHS - on the original set of 3 x AA cells. (They were not even fresh cells!)
At worst case, that's 2400mAh. 4 months is about 3000 hours. So even by those metrics, including running the temp sensor, it's WELL under 1mA.
 
Even in "low-power" mode, in all honesty I can't see a WC8 coming close to that.
 
 

CAI_Support said:

We are thinking it might be worth to add a low power mode, so that only TTL input works, when certain condition met, it will jump up to full power mode to enable network.

Click to expand...

 
This is still an interesting/useful idea.
I've lots of applications where I have WC8 either not connected to the world, or only intermittently connected (and even then, it is usually the WC8 that wants to initiate the connection so it could quite easily wake up first, then do stuff).

We are thinking it might be worth to add a low power mode, so that only TTL input works, when certain condition met, it will jump up to full power mode to enable network.


Checkboxes to select what parts are shut down, with comments stating aprox saved power, would be great, if possible.
 
Also possibly a 10% CPU clock mode or similar.