This module provides an interface to the the MCP 4801, 4802, 4811, 4812, 4821, 4822, 4901, 4902, 4911, 4912, 4921, 4922 digital to analog converters
It uses HiPi::Device::SPI as a backend.
Create a new instance of the module class.
use HiPi qw( :mcp4dac ); use HiPi::Interface::MCP4DAC; my $dac = HiPi::Interface::MCP4DAC->new( devicename => '/dev/spidev0.0', ic => MCP4902, );
devicename gives the SPI device and CS number that the IC is connected to.
ic gives the chip family type. It can be one of the following:
You can optionally set the following properties at object creation. (default values shown)
use HiPi qw( :mcp4dac ); use HiPi::Interface::MCP4DAC; my $dac = HiPi::Interface::MCP4DAC->new( devicename => '/dev/spidev0.0', ic => MCP4902, gain => 0, shiftvalue => 0, buffer => 0, );
$value is the setting you want to apply.
if the current setting of $dac->shiftvalue is false then $value should be a number between 0 and 4095
if the current setting of $dac->shiftvalue is true then the range for $value is determined by the resolution of your converter.
- for an 8 bit device you must specify values 0 - 255
- for a 10 bit device you must specify values 0 - 1023
- for a 12 bit device you must specify values 0 - 4095
$channel is only used when your converter has two channels.
If $channel is 0 or undefined then the write is to channel A
If $channel is any true value and your converter has a second channel then the write is to channel B.
In your code if dealing with a known 2 channel converter you may wish to always be explicit
$dac->write( $aval, 0 ); $dac->write( $bval, 1 );
Code that does not specify a channel always writes to channel A and is portable across all supported converters.
$dac->write( $val );
Flags are included in the write operation according to the current property settings
|gain||If 'gain' is true, the gain bit is set in the write message.|
|buffer||If 'buffer' is true, and your IC can buffer, the buffer bit is set in the write message.|
Shutdown the specified channel by passing the flag defined in the converter datasheets.
$channel is 0 or 1 for channel A or B. Defaults to channel A if $channel undefined.
$dac->shutdown( 0 ); $dac->shutdown( 1 );
Get or set the gain property. True / False ( see 'write' method )
my $gain = $dac->gain(); $dac->gain( 0 ); $dac->gain( 1 );
Get or set the buffer property. True / False ( see 'write' method )
my $buffer = $dac->buffer(); $dac->buffer( 0 ); $dac->buffer( 1 );
Get or set the shiftvalue property. True / False ( see 'write' method )
my $shift = $dac->shiftvalue(); $dac->shiftvalue( 0 ); $dac->shiftvalue( 1 );