Guru
Joined: 18/10/2016
Location: AustraliaPosts: 905
| Posted: 05:07pm 23 Nov 2016 |
Hi - this is a follow-up to my earlier post:
http://www.thebackshed.com/forum/forum_posts.asp?TID=9090&PN=3
As I get further into the detail I have a few more questions that I'm sure will be trivial to most of you (sorry but I have read all the datasheets to no avail):
- I want to sample BMP180 data every 15 minutes and plot it every hour. What are the pros and cons of setting up interrupts (eg as TassieJim does) vs a Do-Loop that tests the times?
- am I correct that "RTC GetTime" not only reads the RTC's time but sets the MM's time (and date) to that value? (all this in the background - brilliant!)
In I2C communications:
- is it OK to connect the SCL and SDA of a BMP180 and a RTC to I2C (17/18) but the Vdd of each to 3.3 and 5V respectively (the latter is so that the RTC's LIR2032 charges) (no smoke so far . . .)
- I have a future project where I want to measure two sets of pressures, one at atmospheric and a second at less than this (well within the BMP180's range) - can I address two BMP180's via I2C? (how)?
- how does one know that the BMP180 address is &H77? (TassieJim's code to read BMP180 temperature and pressure)
- how does one know that the RTC address is &H68? (Geoffg's code for SuperClock)
- what does the instruction "I2C Write &H51, 0, 1, 2" do? (It is applied if the RTC is not present in Geoffg's code for SuperClock)
Thanks again, Andrew.