NXP Semiconductors MKL27Z128VFM4, Reference Manual

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DACx_C2 field descriptions (continued)
Field Description
4
DACBFRP
DAC Buffer Read Pointer
In normal mode it keeps the current value of the buffer read pointer. FIFO mode, it is the FIFO read
pointer. It is writable in FIFO mode. User can configure it to same address to reset FIFO as empty.
3–1
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
0
DACBFUP
DAC Buffer Upper Limit
In normal mode it selects the upper limit of the DAC buffer. The buffer read pointer cannot exceed it. In
FIFO mode it is the FIFO write pointer. User cannot set Buffer Up limit in FIFO mode. In Normal mode its
reset value is MAX. When IP is configured to FIFO mode, this register becomes Write_Pointer, and its
value is initially set to equal READ_POINTER automatically, and the FIFO status is empty. It is writable
and user can configure it to the same address to reset FIFO as empty.
25.5 Functional description
The 12-bit DAC module can select one of the two reference inputs—DACREF_1 and
DACREF_2 as the DAC reference voltage, V
in
by C0 [DACRFS]. See the chip-specific
DAC information to determine the source options for DACREF_1 and DACREF_2.
When the DAC is enabled, it converts the data in DACDAT0[11:0] or the data from the
DAC data buffer to a stepped analog output voltage. The output voltage range is from V
in
to V
in
∕4096, and the step is V
in
∕4096.
25.5.1 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 the 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 a hardware or software trigger event occurs.
The data buffer can be configured to operate in Normal mode, One-Time Scan mode or
FIFO 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].
Chapter 25 12-bit Digital-to-Analog Converter (DAC)
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
Freescale Semiconductor, Inc. 419