Hi Folks,
I wanted to set up my BBB with a pressure sensor. Instead of ordering the BMP180, for which there is good documentation, I mistakenly ordered the BMP183, which uses something called SPI. Can this chip be used with the BBB? If so, would anyone know how the wiring instructions would change?
I don't see any tutorials that describe how to use this, so I may be out of luck.
BMP183 -> BBB
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- adafruit_support_mike
- Posts: 67446
- Joined: Thu Feb 11, 2010 2:51 pm
Re: BMP183 -> BBB
SPI is another common hardware interface protocol. It generally uses four pins:
MOSI - Master Out, Slave In
MISO - Master In, Slave Out
SCK - Data Clock
CS - Chip Select
As the names imply, there are two lines that carry data, each of which has one device talking and the other listening. For each tick of SCK one bit goes each direction, making SPI a full-duplex protocol.
SPI is designed so multiple devices can share the same MOSI, MISO, and SCK pins. The trick to making that happen is the CS signal.
When a slave device's CS pin is low, it listens to MOSI and transmits data on MISO. When its CS pin is high, a device ignores everything that happens on MOSI and puts its MISO pin in a high-impedance state so another chip can use the line.
The Adafruit_BBIO library supports SPI: https://learn.adafruit.com/setting-up-i ... -black/spi
We don't have and code for the BMP183 on the BBB though, so you'd have to port the Arduino code over to Python.
MOSI - Master Out, Slave In
MISO - Master In, Slave Out
SCK - Data Clock
CS - Chip Select
As the names imply, there are two lines that carry data, each of which has one device talking and the other listening. For each tick of SCK one bit goes each direction, making SPI a full-duplex protocol.
SPI is designed so multiple devices can share the same MOSI, MISO, and SCK pins. The trick to making that happen is the CS signal.
When a slave device's CS pin is low, it listens to MOSI and transmits data on MISO. When its CS pin is high, a device ignores everything that happens on MOSI and puts its MISO pin in a high-impedance state so another chip can use the line.
The Adafruit_BBIO library supports SPI: https://learn.adafruit.com/setting-up-i ... -black/spi
We don't have and code for the BMP183 on the BBB though, so you'd have to port the Arduino code over to Python.
-
- Posts: 11
- Joined: Sat Jan 11, 2014 8:25 am
Re: BMP183 -> BBB
Many thanks, Mike. I'll give a look, and let you know if I have any more issues.
Please be positive and constructive with your questions and comments.