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signal.adc.ad799x.spin2
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signal.adc.ad799x.spin2
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{
--------------------------------------------
Filename: signal.adc.ad799x.spin2
Author: Jesse Burt
Description: Driver for Analog Devices AD799x-series ADCs (P2 version)
Copyright (c) 2023
Started Jul 14, 2023
Updated Jul 14, 2023
See end of file for terms of use.
--------------------------------------------
}
CON
SLAVE_WR = core.SLAVE_ADDR
SLAVE_RD = core.SLAVE_ADDR|1
DEF_SCL = 0
DEF_SDA = 1
DEF_HZ = 100_000
DEF_ADDR = 0
I2C_MAX_FREQ = core.I2C_MAX_FREQ
{ default I/O settings; these can be overridden in the parent object }
SCL = DEF_SCL
SDA = DEF_SDA
I2C_FREQ = DEF_HZ
I2C_ADDR = DEF_ADDR
VAR
long _scale, _adc_ref
word _interrupt
word _last_channel
word _last_meas
byte _opmode
OBJ
i2c : "com.i2c" ' I2C engine
core: "core.con.ad799x.spin" ' hw-specific low-level const's
PUB null()
' This is not a top-level object
PUB start(): status
' Start using default I/O settings
return startx(SCL, SDA, I2C_FREQ)
PUB startx(SCL_PIN, SDA_PIN, I2C_HZ): status
' Start using custom IO pins and I2C bus frequency
if ( lookdown(SCL_PIN: 0..63) and lookdown(SDA_PIN: 0..63) )
if ( status := i2c.init(SCL_PIN, SDA_PIN, I2C_HZ) )
waitus(core.T_POR) ' wait for device startup
if ( i2c.present(SLAVE_WR) ) ' test device bus presence
set_ref_voltage(5_000000) ' default to 5V reference
set_model(7993) ' default to AD7993 (10-bit) model
return
' if this point is reached, something above failed
' Re-check I/O pin assignments, bus speed, connections, power
' Lastly - make sure you have at least one free core/cog
return FALSE
PUB stop()
' Stop the driver
i2c.stop()
i2c.deinit()
PUB defaults()
' Set factory defaults
adc_chan_enabled(%0000_0000) ' no channels enabled
PUB preset_prop_boe()
' Preset settings:
' Propeller Board of Education
' AD7993-1
' 5V supply and reference
set_ref_voltage(5_000000)
set_model(7993)
PUB adc_chan_enabled(mask): curr_mask
' Enable one or more ADC channels
' Valid values:
' AD7993, AD7994: %0000..%1111 (ch4..ch1)
' AD7997, AD7998: %0000_0000..%1111_1111 (ch8..ch1)
' Any other value polls the chip and returns the current setting
if ( _opmode ) ' temporarily stop measurements if they're running
i2c.stop()
curr_mask := 0
{ handle model-specific differences below; reg size, masks, etc }
readreg(core.CONFIG, core.CONFIG_REGSZ, @curr_mask)
case mask
0..core.CH_BITS:
mask := ((curr_mask & core.CH_MASK) | (mask << core.CH) )
writereg(core.CONFIG, core.CONFIG_REGSZ, @mask)
other:
return ((curr_mask >> core.CH) & core.CH_BITS)
opmode(_opmode)
PUB adc_data(): w
' ADC data word
' Returns: 10 or 12-bit ADC word (dependent on model set with set_model() )
return _last_meas := i2c.rdword_msbf(i2c.ACK)
pub adc_data_rate(rate): curr_rate | tmp
' Set ADC data rate (interval between measurements as a function of (Tconvert * rate) )
' Valid values: 32, 64, 128, 256, 512, 1024, 2048
if ( _opmode )
i2c.stop()
curr_rate := 0
readreg(core.CYC_TMR, 1, @curr_rate)
case rate
32..2048:
rate := ( ( encod (rate >> 4)-1 ) )
rate := ((curr_rate & core.CYC_MASK) | rate)
writereg(core.CYC_TMR, 1, @rate)
other:
curr_rate := (1 << (curr_rate & core.CYC_BITS) << 4 )
opmode(_opmode)
pub adc2volts(adc_word): volts
' Scale ADC word to microvolts
return (adc_word >> 2) * _scale
con #0, NO_INT, BUSY_OUT, INT_OUT ' valid modes for alert_busy_pin_mode()
pub alert_busy_pin_mode(mode): curr_mode
' Set mode/function of the ALERT/BUSY pin
' Valid values:
' NO_INT (0): no interrupt signal
' BUSY_OUT (1): pin functions as a busy output/data ready signal
' INT_OUT (2): pin functions as an interrupt output
if ( _opmode )
i2c.stop()
curr_mode := 0
readreg(core.CONFIG, core.CONFIG_REGSZ, @curr_mode)
case mode
NO_INT, BUSY_OUT, INT_OUT:
mode := ( (curr_mode & core.ALT_BSY_MASK) | (mode << core.BUSY_ALERT) )
writereg(core.CONFIG, core.CONFIG_REGSZ, @mode)
other:
curr_mode := ((curr_mode >> core.BUSY_ALERT) & core.ALT_BSY_BITS)
opmode(_opmode)
pub interrupt(): i
' Flag indicating threshold interrupt asserted
return ( _last_meas >> core.ALRT_FLAG) & 1
pub last_channel_read(): ch
' Get the channel number last read
return (( _last_meas >> core.CH_ID) & core.CH_ID_BITS)
con #0, STOPPED, CONT
pub opmode(mode): curr_mode
' Set operating mode
' Valid values:
' CONT (1), or non-zero: continuous measurement at interval specified by adc_data_rate()
' STOPPED (0): stopped
' NOTE: In continuous measurement mode, the I2C bus __is left active__ (addressed to AD799x)
' Ensure no other bus activity can occur while this is true, or set opmode(0) if other
' bus activity is required.
if ( mode )
i2c.start()
i2c.write(SLAVE_WR)
i2c.write(core.CONV)
i2c.stop()
i2c.start()
i2c.write(SLAVE_RD)
else
i2c.stop()
_opmode := mode
PUB set_model(model)
' Set ADC model
' Valid values:
' 7993, 7994, 7997, 7998
case model
7993, 7997:
_scale := _adc_ref / 1024 ' 10-bit
7994, 7998:
_scale := _adc_ref / 4096 ' 12-bit
PUB set_ref_voltage(v): curr_v
' Set ADC reference/supply voltage (Vdd), in microvolts
' Valid values: 1_200_000..5_500_000 (1.2 .. 5.5V)
_adc_ref := (1_200000 #> v <# 5_500000)
PRI readreg(reg_nr, nr_bytes, ptr_buff) | cmd_pkt
' Read nr_bytes from the device into ptr_buff
case reg_nr ' validate register num
$01..$0F:
cmd_pkt.byte[0] := SLAVE_WR
cmd_pkt.byte[1] := reg_nr
i2c.start()
i2c.wrblock_lsbf(@cmd_pkt, 2)
i2c.stop()
i2c.start()
i2c.wr_byte(SLAVE_RD)
i2c.rdblock_msbf(ptr_buff, nr_bytes, i2c.NAK)
i2c.stop()
other: ' invalid reg_nr
return
PRI writereg(reg_nr, nr_bytes, ptr_buff) | cmd_pkt
' Write nr_bytes to the device from ptr_buff
case reg_nr
$01..$0F:
cmd_pkt.byte[0] := SLAVE_WR
cmd_pkt.byte[1] := reg_nr
i2c.start()
i2c.wrblock_lsbf(@cmd_pkt, 2)
i2c.wrblock_msbf(ptr_buff, nr_bytes)
i2c.stop()
other:
return
#include "signal.adc.common.spin2h"
DAT
{
Copyright 2023 Jesse Burt
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
}