Information

34.5.1 DAC data buffer operation
When the DAC is enabled and the buffer is not enabled, the DAC module always
converts the data in DAT0 to analog output voltage.
When both the DAC and the buffer are enabled, the DAC converts the data in the data
buffer to analog output voltage. The data buffer read pointer advances to the next word
whenever any hardware or software trigger event occurs. Refer to Introduction for the
hardware trigger connection.
The data buffer can be configured to operate in Normal mode, Swing mode, or One-Time
Scan mode. When the buffer operation is switched from one mode to another, the read
pointer does not change. The read pointer can be set to any value between 0 and
C2[DACBFUP] by writing C2[DACBFRP].
34.5.1.1 DAC data buffer interrupts
There are several interrupts and associated flags that can be configured for the DAC
buffer. SR[DACBFRPBF] is set when the DAC buffer read pointer reaches the DAC
buffer upper limit, that is, C2[DACBFRP] = C2[DACBFUP]. SR[DACBFRPTF] is set
when the DAC read pointer is equal to the start position, 0. Finally, SR[DACBFWMF] is
set when the DAC buffer read pointer has reached the position defined by
C1[DACBFWM]. C1[DACBFWM] can be used to generate an interrupt when the DAC
buffer read pointer is between 1 to 4 words from C2[DACBFUP].
34.5.1.2 Modes of DAC data buffer operation
The following table describes the different modes of data buffer operation for the DAC
module.
Table 34-47. Modes of DAC data buffer operation
Modes Description
Buffer Normal mode
This is the default mode. The buffer works as a circular buffer.
The read pointer increases by one, every time the trigger
occurs. When the read pointer reaches the upper limit, it goes
to 0 directly in the next trigger event.
Buffer Swing mode
This mode is similar to the normal mode. However, when the
read pointer reaches the upper limit, it does not go to 0. It will
descend by 1 in the next trigger events until 0 is reached.
Table continues on the next page...
Functional description
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
800
Preliminary
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