Now that both the Microduino and the BLE112 are completely setup and programmed / programmable, we can connect the two. Both modules talk through a standard serial connection, but we also add 2 wakeup feeds and a reset feed for better control and low power optimizations.
1.) review Schematic
This is the last connection required to complete the core functionality of the OSWatch. Remember that beer you put in the fridge? You get to open it up in one more page . . .
2.) Connect Reset to Pin 4
When you connected the programming reset pin, you should have added an extra line of microwire for future use. Now connect that extra feed to digital pin 4 on the Microduino. This is used to reset the BLE112 when the module powers up.
3.) Connect the Serial communication
run two lines from p0_4 & p0_5 to Microduino digital pins 2 & 7 respectively. We use pin 2 for the RX on the Micorduino since that pin supports interrupts. For the transmission pin, we use pin 7 as no interrupt is needed to transmit. That lets us free up the interrupt on pin 3 for a wakeup signal we'll connect shortly.
4.) Connect the 2 Wake Connections
In the BLE112 firmware BGLib_U1A1P_38400 noflow_wake16_hwake15, we enabled two pins to provide advanced power saving options. At the moment the software does not use these, but the goal is to incorperate them in the future. One feed runs from BLE112 p1_5 to Microduino digital pin 3. This is attached to an interrupt feed, and is used prior to any BLE112 message transmission. This will let the software put the microduino to sleep until the BLE112 wakes it up with a message. The second connection (BLE112 p1_6 to Microduino digital pin 5) will enable the Microduino to put the BLE112 to sleep and wake it up.
5.) Check your work
Break out that multimeter, and check those connections. The next step will be firing the logic board up, so it's best to check your work before that. (For example, I screwed up and reversed p0_4 & p0_5. I wasted 30 minutes on the next step, thinking something else was wrong.)
Updated June 3, 2014