Digital-to-analog converter (DAC1)
RM0365
395/1080
DocID025202 Rev 7
16.4
DAC channel enable
The DAC channel can be powered on by setting the EN1 bit in the DAC_CR register. The
DAC channel is then enabled after a startup time t
WAKEUP
.
Note:
The EN1 bit enables the analog DAC Channel macrocell only. The DAC Channel digital
interface is enabled even if the EN1 bit is reset.
16.5
Single mode functional description
16.5.1
DAC data format
There are three possibilities:
•
8-bit right alignment: the software has to load data into the DAC_DHR8Rx [7:0] bits
(stored into the DHRx[11:4] bits)
•
12-bit left alignment: the software has to load data into the DAC_DHR12Lx [15:4] bits
(stored into the DHRx[11:0] bits)
•
12-bit right alignment: the software has to load data into the DAC_DHR12Rx [11:0] bits
(stored into the DHRx[11:0] bits)
Depending on the loaded DAC_DHRyyyx register, the data written by the user is shifted and
stored into the corresponding DHRx (data holding registerx, which are internal non-memory-
mapped registers). The DHRx register is then loaded into the DORx register either
automatically, by software trigger or by an external event trigger.
Figure 112. Data registers in single DAC channel mode
16.5.2
DAC channel conversion
The DAC_DORx cannot be written directly and any data transfer to the DAC channelx must
be performed by loading the DAC_DHRx register (write to DAC_DHR8Rx, DAC_DHR12Lx,
DAC_DHR12Rx).
Data stored in the DAC_DHRx register are automatically transferred to the DAC_DORx
register after one APB1 clock cycle, if no hardware trigger is selected (TENx bit in DAC_CR
register is reset). However, when a hardware trigger is selected (TENx bit in DAC_CR
register is set) and a trigger occurs, the transfer is performed three PCLK1 clock cycles
later.
When DAC_DORx is loaded with the DAC_DHRx contents, the analog output voltage
becomes available after a time t
SETTLING
that depends on the power supply voltage and the
analog output load.
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