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|
#########################################################################################
# Package HiPi::Interface::MS5611
# Description : Interface to MS5611_01BA03 barometric pressure sensor
# Copyright : Copyright (c) 2013-2023 Mark Dootson
# License : This is free software; you can redistribute it and/or modify it under
# the same terms as the Perl 5 programming language system itself.
#########################################################################################
package HiPi::Interface::MS5611;
#########################################################################################
use strict;
use warnings;
use parent qw( HiPi::Interface::Common::Weather );
use HiPi qw( :i2c :rpi :ms5611);
use HiPi::RaspberryPi;
use Carp;
our $VERSION ='0.89';
__PACKAGE__->create_accessors( qw( backend crc) );
use constant {
CMD_RESET => 0x1E,
CMD_ADC_READ => 0x00, # // ADC read command
CMD_ADC_CONV => 0x40, # // ADC conversion command
CMD_ADC_D1 => 0x00, # // ADC D1 conversion
CMD_ADC_D2 => 0x10, # // ADC D2 conversion
CMD_PROM_RD => 0xA0, # // Prom read command
};
sub new {
my ($class, %userparams) = @_;
my $pi = HiPi::RaspberryPi->new();
my %params = (
devicename => ( $pi->board_type == RPI_BOARD_TYPE_1 ) ? '/dev/i2c-0' : '/dev/i2c-1',
address => 0x76,
device => undef,
backend => 'i2c',
);
# get user params
foreach my $key( keys (%userparams) ) {
$params{$key} = $userparams{$key};
}
if( $params{busmode} ) {
$params{backend} = $params{busmode};
}
unless( defined($params{device}) ) {
if ( $params{backend} eq 'bcm2835' ) {
require HiPi::BCM2835::I2C;
$params{device} = HiPi::BCM2835::I2C->new(
address => $params{address},
peripheral => ( $params{devicename} eq '/dev/i2c-0' ) ? HiPi::BCM2835::I2C::BB_I2C_PERI_0() : HiPi::BCM2835::I2C::BB_I2C_PERI_1(),
);
} else {
require HiPi::Device::I2C;
$params{device} = HiPi::Device::I2C->new(
devicename => $params{devicename},
address => $params{address},
busmode => 'i2c', # don't smbus
);
}
}
my $self = $class->SUPER::new(%params);
$self->_init;
return $self;
}
sub reset {
my $self = shift;
$self->device->bus_write( CMD_RESET );
$self->delay( 3 );
return;
}
sub _read_prom {
my($self, $coefnum) = @_;
$self->device->bus_write( CMD_PROM_RD + $coefnum * 2 );
my @ret = $self->device->bus_read( undef, 2);
my $prom = $ret[0] * 256 + $ret[1];
return $prom;
}
sub _crc4 {
my( $self ) = @_;
# int cnt; // simple counter
# unsigned int n_rem; // crc reminder
# unsigned int crc_read; // original value of the crc
# unsigned char n_bit;
my $n_rem = 0x00;
my $crc_read = $self->crc->[7];
$self->crc->[7] = 0;
for (my $cnt = 0; $cnt < 16; $cnt ++) { #// operation is performed on bytes
# // choose LSB or MSB
if ( $cnt % 2 ==1 ) {
$n_rem ^= (($self->crc->[$cnt>>1]) & 0x00FF);
} else {
$n_rem ^= ( $self->crc->[$cnt>>1] >> 8);
}
for (my $n_bit = 8; $n_bit > 0; $n_bit--) {
if ($n_rem & 0x8000) {
$n_rem = ($n_rem << 1) ^ 0x3000;
} else {
$n_rem = $n_rem << 1;
}
}
}
$n_rem= (0x000F & ($n_rem >> 12)); #// // final 4-bit remainder is CRC code
$self->crc->[7] = $crc_read; # // restore the crc_read to its original place
return $n_rem ^ 0x00;
}
sub _init {
my $self = shift;
my @promvals = ();
# get callibration coeffs
for ( my $i = 0; $i < 8 ; $i++ ) {
my $promval = $self->_read_prom( $i );
push @promvals, $promval;
}
$self->crc( \@promvals );
my $n_crc = $self->_crc4( @promvals );
# is the crc check worth it ?????
}
sub _adc_cmd {
my( $self, $cmd ) = @_;
$self->device->bus_write( CMD_ADC_CONV + $cmd );
my $osr = $cmd & 0x0F;
if( $osr == MS5611_OSR_256 ) {
$self->delay(1);
} elsif($osr == MS5611_OSR_512 ) {
$self->delay(3);
} elsif($osr == MS5611_OSR_1024 ) {
$self->delay(4);
} elsif($osr == MS5611_OSR_2048 ) {
$self->delay(6);
} else {
$self->delay(10);
}
$self->device->bus_write( CMD_ADC_READ );
my @ret = $self->device->bus_read( undef, 3);
my $result = ($ret[0] * 65536 ) + ($ret[1] * 256 ) + $ret[2];
return $result;
}
sub _internal_read_p_t {
my($self, $pres_osr, $temp_osr ) = @_;
$pres_osr //= MS5611_OSR_4096;
$temp_osr //= MS5611_OSR_4096;
my $D2 = $self->_adc_cmd( CMD_ADC_D2 + $temp_osr);
my $D1 = $self->_adc_cmd( CMD_ADC_D1 + $pres_osr);
my $dT = $D2 - $self->crc->[5] * (2**8);
my $OFF = $self->crc->[2] * (2**16) + $dT * $self->crc->[4] / (2**7);
my $SENS = $self->crc->[1] * (2**15) + $dT * $self->crc->[3] / (2**8);
my $TEMP = 2000 + ( $dT * $self->crc->[6]) / ( 2**23 );
if( $TEMP < 2000 ) {
my $T2 = ($dT**2) / (2**31);
my $OFF2 = 5 * ($TEMP - 2000)**2 / 2;
my $SENS2 = 5 * ($TEMP - 2000)**2 / 2**2;
if( $TEMP < -1500 ) {
$OFF2 = $OFF2 + 7 * ( $TEMP + 1500 )**2;
$SENS2 = $SENS2 + 11 * ($TEMP + 1500)**2 / 2;
}
$TEMP -= $T2;
$SENS -= $SENS2;
$OFF -= $OFF2;
}
my $P = ( ($D1 * $SENS) / (2**21) - $OFF ) / ( 2**15 );
return ( $P , $TEMP );
}
sub read_pressure_temp {
my($self, $pres_osr, $temp_osr ) = @_;
my ( $pressure, $temperature ) = $self->_internal_read_p_t( $pres_osr, $temp_osr );
return ( sprintf('%.4f', $pressure / 100), sprintf('%.2f', $temperature / 100 ) );
}
sub read_pressure_pa_temp {
my($self, $pres_osr, $temp_osr ) = @_;
my ( $pressure, $temperature ) = $self->_internal_read_p_t( $pres_osr, $temp_osr );
return ( sprintf('%.2f', $pressure ), sprintf('%.2f', $temperature / 100 ) );
}
1;
__END__
|
