Table 182. Channel Output Modes Summary - ST STM32G4 Series Reference Manual

RM0440
To disabled the output buffer, The MODEx[2:0] bits in DAC_MCR register should be:
•
110: DAC is connected to external pin and to on chip peripherals
•
111: DAC is connected to on chip peripherals
When MODEx[2:0] bits in DAC_MCR register is equal to 111. An internal capacitor, C
hold the voltage output of the DAC Core and then drive it to on-chip peripherals.
All Sample and Hold phases are interruptible and any change in DAC_DHRx will trigger
immediately a new sample phase.
Note: The sawtooth wave generation is not supported in Sample and Hold mode operation.
x
MODE [2:0] Mode
0 0 0
0 0 1
Normal mode
0 1 0
0 1 1
1 0 0
1 0 1
Sample and
Hold mode
1 1 0
1 1 1
21.4.13 DAC channel buffer calibration
The transfer function for an N-bit digital-to-analog converter (DAC) is:
Where V
scale voltage, and V
Due to output buffer characteristics, the voltage offset may differ from part-to-part and
introduce an absolute offset error on the analog output. To compensate the V
is required by a trimming technique.
The calibration is only valid when the DAC channelx is operating with buffer enabled
(MODEx[2:0] = 000b or 001b or 100b or 101b). if applied in other modes when the buffer is
off, it has no effect. During the calibration:
• The buffer output will be disconnected from the pin internal/external connections and
put in tristate mode (HiZ).
•
The buffer will act as a comparator, to sense the middle-code value 0x800 and
compare it to VREF+/2 signal through an internal bridge, then toggle its output signal to
0 or 1 depending on the comparison result (CAL_FLAGx bit).

Table 182. Channel output modes summary

Buffer
Connected to external pin
Enabled
Connected to external pin and to on chip-peripherals (ex, comparators)
Connected to external pin
Disabled
Connected to on chip peripherals (ex, comparators)
Connected to external pin
Enabled
Connected to external pin and to on chip peripherals (ex, comparators)
Connected to external pin and to on chip peripherals (ex, comparators)
Disabled
Connected to on chip peripherals (ex, comparators)
V
out
is the analog output, D is the digital input, G is the gain, V
OUT
is the offset voltage. For an ideal DAC channel, G = 1 and V
os
Output connections
2 N 1 –
( ( ⁄ ) × ×
= D G
RM0440 Rev 1
Digital-to-analog converter (DAC)
)
V + V
ref OS
is the nominal full-
ref
will
,
Lint
= 0.
os
, a calibration
os
705/2083
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