Difference between revisions of "Project:HM55B"

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[http://www.parallax.com/dl/docs/prod/compshop/HM55BModDocs.pdf Datasheet]
 
[http://www.parallax.com/dl/docs/prod/compshop/HM55BModDocs.pdf Datasheet]
  
 +
== Bus Pirate pinout ==
 +
 +
From http://dangerousprototypes.com/docs/Bus_Pirate_101_tutorial
 +
 +
<pre>
 +
Pin name Description (Bus Pirate is the master)
 +
MOSI Master data out, slave in (SPI, JTAG), Serial data (1-Wire, I2C, KB), TX* (UART)
 +
CLK Clock signal (I2C, SPI, JTAG, KB)
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MISO Master data in, slave out (SPI, JTAG) RX (UART)
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CS* Chip select (SPI), TMS (JTAG)
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AUX Auxiliary IO, frequency probe, pulse-width modulator
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ADC Voltage measurement probe (max 6volts)
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Vpu Voltage input for on-board pull-up resistors (0-5volts).
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+3.3v +3.3volt switchable power supply
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+5.0v +5volt switchable power supply
 +
GND Ground, connect to ground of test circuit
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</pre>
  
 
== Testing with the BusPirate ==
 
== Testing with the BusPirate ==

Revision as of 22:26, 9 December 2010

About the module

$20-25 compass module for embedded systems. SMD will be cheaper.

Datasheet

Bus Pirate pinout

From http://dangerousprototypes.com/docs/Bus_Pirate_101_tutorial

Pin name Description (Bus Pirate is the master)
MOSI 	Master data out, slave in (SPI, JTAG), Serial data (1-Wire, I2C, KB), TX* (UART)
CLK 	Clock signal (I2C, SPI, JTAG, KB)
MISO 	Master data in, slave out (SPI, JTAG) RX (UART)
CS* 	Chip select (SPI), TMS (JTAG)
AUX 	Auxiliary IO, frequency probe, pulse-width modulator
ADC 	Voltage measurement probe (max 6volts)
Vpu 	Voltage input for on-board pull-up resistors (0-5volts).
+3.3v 	+3.3volt switchable power supply
+5.0v 	+5volt switchable power supply
GND 	Ground, connect to ground of test circuit 

Testing with the 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 readings:

0,-6

-1,-11

-1,-19