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GD32F403xx User Manual
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in the DAC_CTL register.
13.3.3.
DAC data configuration
The 12-bit DAC holding data (DACx_DH) can be configured by writing any one of these
registers (DACx_R12DH, DACx_L12DH or DACx_R8DH). When the data is loaded into
DACx_R8DH register, only the MSB 8 bits are configurable, the LSB 4 bits are fored to
4’b0000.
13.3.4.
DAC trigger
The DAC external trigger is enabled by setting the DTENx bits in the DAC_CTL register. The
DAC external triggers are selected by the DTSELx bits in the DAC_CTL register.
Table 13-2. External triggers of DAC
DTSELx[2:0]
Trigger Source
Trigger Type
3b’000
TIMER5_TRGO
Hardware trigger
3b’001
TIMER2_TRGO
3b’010
TIMER6_TRGO
3b’011
Reserved
3b’100
Reserved
3b’101
TIMER3_TRGO
3b’110
EXTI9
External signal
3b’111
SWTRIG
Software trigger
The TIMERx_TRGO signals are generated from the timers, while the software trigger can be
generated by setting the SWTRx bits in the DAC_SWT register.
13.3.5.
DAC workflow
If the external trigger is enabled by setting the DTENx bit in DAC_CTL register, the DAC
holding data is transferred to the DAC output data (DACx_DO) register when the selected
trigger event happened. When the external trigger is disabled, the transfer is performed
automatically.
When the DAC holding data (DACx_DH) is loaded into the DACx_DO register, after the time
t
SETTLING
, the analog output is valid, and the value of t
SETTLING
is related to the power supply
voltage and the analog output load.
13.3.6.
DAC noise wave
There are two methods of adding noise wave to the DAC output data: LFSR noise wave mode
and Triangle wave mode. The noise wave mode can be selected by the DWMx bits in the
DAC_CTL register. The amplitude of the noise can be configured by the DAC noise wave bit
width (DWBWx) bits in the DAC_CTL register.