Thank you - good questions, and you are correct, the build manual is not ready yet.
1) The orientation of the variable capacitor does not matter as it is not a polarized capacitor
2) You are correct, the jumpers determine the address.
The MCP23017 can be addressed at I2C addresses 0x20-0x27
As there are two IC's on Pi Rtc Dio, address line A0 is used to select the IC. IC1 has A0=0, and IC2 has A0=1
There can be four Pi Rtc Dio boards on an I2C bus (only one may have the RTC section populated)
Board 0:
IC1 J1 A1 = 0, A2 = 0
IC2 J1 A1 = 0, A2 = 0
Board 1:
IC1 J1 A1 = 0, A2 = 1
IC2 J1 A1 = 0, A2 = 1
Board 2:
IC1 J1 A1 = 1, A2 = 0
IC2 J1 A1 = 1, A2 = 0
Board 3:
IC1 J1 A1 = 1, A2 = 1
IC2 J1 A1 = 1, A2 = 1
Please excuse the poor quality of the attached image, the version for the manual will look much better.
I hope to have the manual uploaded sometime next week.
- Pi_Rtc_Dio_Jumpers.jpg (317.63 KiB) Viewed 16503 times
gmeister wrote:I am presently building the Pi Rtc Dio Gold kit and the Build Manual is not available yet. For the most part, the excellent photos on the Mikronauts site are sufficient to build from, but I do have a couple of questions that can't be answered from the photos.
The kit comes with a trim capacitor which has a flat side, suggesting that it might have polarity, but the silk screen on the board doesn't seem to indicate this. Does the orientation of the trim capacitor matter?
There are four jumper positions located under the DIP sockets for the MCP23017's, J1 through J4. I am sure that these are for determining the I2C addresses of the two DIO chips. I could experiment to figure out what addresses are available, but is there a table that can be provided that spells this out?
Thank you.