I’d like to modify the si4735 shield to support I2C with my Netduino. I’ve seen http://n8vhf.com/2012/02/01/i2c-modific … io-shield/ and http://mbed.org/users/bwilson30/noteboo … -receiver/, and (have more-or-less) successfully removed the 74hc4050 and bridged the pads. But I’m still confused about which pins should be connected to what.
Brett Wilson suggests setting GPO1 to +3.3v and grounding GPO2 to enable I2C mode. However, on the Netduino forum, reader Hanzibal points out that GPO2 on this shield is connected to a pull-up resistor, and that simply grounding GPO2 could cause a short-circuit.
Right now, my best guess for the pinout is:
Pin 2 - INT - Netduino pin D13 (using Brian’s example)
**Pin 3 - GPO2 - ground ** short-circuit? **
Pin 8 - RAD_PWR - +3.3 v
Pin 9 - RAD_RESET - reset
Pin 10 - SEN - ground (enable serial mode)
Pin 11 - SDA - Netduino pin A4 (don’t forget the pull-up resistors!)
**Pin 12 - GPO1 - +3.3 v ** not necessary? **
Pin 13 - SCL - Netduino pin A5 (don’t forget the pull-up resistors!)
AREF - ground
Thoughts or suggestions would be a great help!