Channel Map
The instructions and specification of the SPI interface and general usage information of the DAC is given in the DAC datasheet, which should be used in conjunction with this page.
Reset State
After power up or after reset, the default value for all channels is 0x000.
| Channel Number | Configuration Type | Mnemonic | Description |
|---|---|---|---|
| 0 | Analog | d_heater | Set the PWM duty cycle for the heater |
| 1 | Analog | d_peltier | Set the PWM duty cycle for the peltier element |
| 2 | Analog | d_fan | Set the PWM duty cycle for the fan |
| 3 | - | ||
| 4 | Digital | p_heater | Set the polarity of the output for the heater, (by default disabled by hardware) |
| 5 | Digital | p_peltier | Set the polarity of the output for the peltier element |
| 6 | Digital | p_fan | Set the polarity of the output for the fan, (by default disabled by hardware) |
| 7 | - |
Duty Cycle Setting
To obtain the transfer function from dac counts "n" to duty cycle "d" for each
channel consult the documentation pages for ./dac and
../pwm/pwm.md.
Polarity Setting
Setting a value of 0x000 at the digital channels sets the polarity to
positive. I.e. current flows from positive output to negative output. Setting a
value of 0xFFF at the digital channels sets the polarity to negative. I.e.
current flows from positive output to negative output.
Defaults to 0x000 on power up.