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signal.adc.md

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signal.adc

API for analog to digital converter device drivers

Object filename description:

signal.adc.model.spin2

model indicates the manufacturer's model number of the ADC

Base Methods

These are methods that are common to all power sensor drivers

Method Description Param Returns
startx() Start driver using explicitly defined settings Notes 1-3 cog id+1
stop() Stop the driver n/a n/a
defaults() Set sensor factory default settings n/a n/a

Notes:

  1. For SPI-connected sensors:

    • startx(CS_PIN, SCK_PIN, MOSI_PIN, MISO_PIN, SPI_FREQ): status
    • SPI_FREQ defaults to 1MHz, if unspecified.
    • For some devices, a MODEL_SPI_BC variant exists, which directs the driver to use a bytecode-based engine that while much slower, doesn't use another cog.
    • For SPI-connected sensors: 4-wire SPI is used by default. If supported by the device, 3-wire SPI can be chosen by setting MOSI_PIN and MISO_PIN to the same I/O pin. The startx() method will check for this and set the device's 3-wire SPI mode register.

  2. For I2C-connected sensors:

    • startx(SCL_PIN, SDA_PIN, I2C_FREQ, ADDR_BITS): status
    • For some devices, a MODEL_I2C_BC variant exists, which directs the driver to use a bytecode-based engine that while much slower, doesn't use another cog.
    • Not all devices support alternate I2C addresses.

  3. startx() returns the launched cog number+1 of com engine used on success.

  4. startx() returns FALSE (0) if the driver fails to start, for these possible reasons:

    • No more cogs available
    • One or more specified I/O pins are outside allowed range
    • Bus frequency is outside allowed range
    • If supported by the device, dev_id() didn't return the expected value

  5. defaults() may simply call reset(), if sensible, as opposed to calling several other driver methods, in order to reduce memory usage.

  6. Drivers may have one or more preset_() methods, that establish a set of pre-set settings.

  7. stop() performs the following tasks:

    • Stop any extra cogs that were started (if applicable)
    • Clear all global variable space used to 0

Methods

Method Description
adc_channel() Get currently set ADC channel
adc_data() Bus voltage ADC word
adc2volts() Convert bus voltage ADC word to voltage
set_adc_channel() Set ADC channel for subsequent reads
voltage() Bus voltage measurement

adc_channel()

Get currently set ADC channel

  • Parameters: none
  • Returns: currently set ADC channel

adc_data()

Bus voltage ADC word

  • Parameters: none
  • Returns: ADC word representing voltage

adc2volts(adc_wd)

Convert bus voltage ADC word to voltage

  • Parameters: adc_wd: ADC word representing voltage
  • Returns: voltage in microvolts

set_adc_channel(ch)

Set ADC channel for subsequent reads

  • Parameters: ch: new channel number
  • Returns: none

voltage()

Bus voltage measurement

  • Parameters: none
  • Returns: voltage in microvolts

Notes:

  1. uV = microvolts
  2. Some devices may include additional methods (e.g., for interrupt support)

File Structure

signal.adc.model.spin - driver object
|-- #include: signal.adc.common.spinh - provides standard API
|-- OBJ: HW-specific constants (core.con.model.spin)
|-- OBJ: Low-level communications engine (I2C, SPI, OneWire, etc)