Nations Technologies Inc.
Tel
:
+86-755-86309900
:
info@nationstech.com
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
390
/
631
DAC trigger
Configure DAC_CTRL.TEN = 1 can enable external trigger of DAC, and DAC_CTRL.TSEL [2:0] is configured to
select an external triggering event as the external triggering source for the DAC.
Table 18-2 DAC external trigger
Trigger source
Type
TSEL[2:0]
Timer 6 TRGO events
Internal signal
from the on-
chip timer
000
Timer 8 TRGO events
001
Timer 7 TRGO events
010
Timer 5 TRGO events
011
Timer 2 TRGO events
100
Timer 4 TRGO events
101
EXTI line 9
External pins
110
SWTRIG (Software Triggered)
Software
control bit
111
When the DAC is triggered by timer output or the rising edge of EXTI line 9, when triggered, the data in the aligned
data hold register will be transferred to the DAC_DATO register. This data transfer process takes 3 APB1 clock
cycles.
DAC_SOTTR.TREN = 1 can enable the DAC software trigger. When the DAC is triggered by the software, the data
of the aligned data hold register will be transmitted to the DAC_DATO register.
Note:
1. Do not change the DAC_CTRL.TSEL[2:0] bit when the DAC is enabled.
2
.
It takes 1 APB1 clock cycle for the data of the aligned data holding register to be transferred to the DAC_DATO
register when software by software.
DAC conversion
If DAC trigger is on, the data in the DAC alignment data hold register will be transferred to the DAC_DATO register
after three APB1 cycles according to the selected trigger event when the hardware trigger occurs. When the software
trigger occurs, the data in the DAC alignment data hold register is transferred to the DAC_DATO register after one
APB1 cycle.If trigger is not enabled, data in the DAC alignment data hold register is automatically transferred to the
DAC_DATO register after one APB1 cycle.
After the DAC transfers data to the DAC_DATO register from its data hold register, the output is valid for the time
tSETTTLING, which is related to the supply voltage and the analog output load.