K60P100M100SF2RM Datasheet, PDF (893/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Chapter 36 12-bit Digital-to-Analog Converter (DAC)
36.5.1 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 in
the event the hardware trigger or the software trigger occurs. Refer to the PDB Module
Interconnections section in Chip Configuration chapter 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
DACBFUP by writing DACBFRP in C2 register.
36.5.1.1 DAC Data Buffer Interrupts
There are several interrupts and associated flags that can be configured for the DAC
buffer. The DAC read pointer bottom position flag is set when the DAC buffer read
pointer reaches the DAC buffer upper limit. ( DACBFRP = DACBFUP). The DAC read
pointer top position flag is set when the DAC read pointer is equal to the start position, 0.
Finally, the DAC buffer watermark flag is set when the DAC buffer read pointer has
reached the position defined by the DAC watermark select bit field. The DAC watermark
select (DACBFWM) can be used to generate an interrupt when the DAC buffer Read
pointer is between 1 to 4 words from the DAC buffer upper limit.
36.5.1.2 Buffer Normal Mode
This is the default mode. The buffer works as a circular buffer. The read pointer increases
by one, every time when the trigger occurs. When the read pointer reaches the upper
limit, it goes to the zero directly in the next trigger event.
36.5.1.3 Buffer Swing Mode
This mode is similar to the normal mode. But when the read pointer reaches the upper
limit, it does not go to the zero. It will descend by one in the next trigger events until zero
is reached.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
893