Project:HM55B: Difference between revisions
From London Hackspace Wiki
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Note that &:50000 isn't enough of a delay, but && works, presumably because BusPirate parser adds a huge delay. This means that we don't know how fast this module can be clocked, because each ! will be > 50ms apart. | Note that &:50000 isn't enough of a delay, but && works, presumably because BusPirate parser adds a huge delay. This means that we don't know how fast this module can be clocked, because each ! will be > 50ms apart. | ||
The [http://dangerousprototypes.com/docs/SPI BusPirate wiki] suggests this will work (since we've determined that it still provides the 22 sample bits even if the reading is incomplete): | |||
\[0b0000 &] | |||
[0b1000 && ]&[& 0b1100 r:4] | |||
Revision as of 00:12, 3 September 2010
Module
$20-25 compass module for embedded systems. SMD will be cheaper.
Testing with the BusPirate
BusPirate settings:
- M (mode)
- 8 (3-wire raw)
- 4 (400KHz)
- 2 (3.3V high)
- W (turn on 5V output)
Reset:
\[/_\/_\/_\/_\&:10]
The delay may not be needed.
Take sample (1100 is the response for success, 00xx is for incomplete, xx11 is error, see p9 of datasheet)
\[/-\/_\/_\/_\&&]&:10[&:10/-\/-\/_\/_\!!!!&!!!!!!!!!!!&!!!!!!!!!!!]
READ BIT: 1 READ BIT: 1 READ BIT: 0 READ BIT: 0 DELAY 0b00000001uS READ BIT: 0 READ BIT: 0 READ BIT: 0 READ BIT: 0 READ BIT: 0 READ BIT: 0 READ BIT: 1 READ BIT: 0 READ BIT: 0 READ BIT: 0 READ BIT: 0 DELAY 0b00000001uS READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 1 READ BIT: 0 READ BIT: 0
Note that &:50000 isn't enough of a delay, but && works, presumably because BusPirate parser adds a huge delay. This means that we don't know how fast this module can be clocked, because each ! will be > 50ms apart.
The BusPirate wiki suggests this will work (since we've determined that it still provides the 22 sample bits even if the reading is incomplete):
\[0b0000 &] [0b1000 && ]&[& 0b1100 r:4]
Sample values:
0,-6
-1,-11
-1,-19
