MC9S12E128CFUE Datasheet, PDF (240/606 Pages) Freescale Semiconductor, Inc – MC9S12E128 Data Sheet

Chapter 7 Digital-to-Analog Converter (DAC8B1CV1)
7.3.2 Register Descriptions
This section consists of register descriptions arranged in address order. Each description includes a
standard register diagram with an associated figure number. Details of register bit and field function follow
the register diagrams, in descending bit order.
7.3.2.1 DAC Control Register 0 (DACC0)
Module Base + 0x0000
R
W
Reset
7
DACE
0
6
5
DACTE
0
4
3
2
0
DJM
DSGN
0
0
0
0
0
= Unimplemented or Reserved
Figure 7-3. DAC Control Register 0 (DACC0)
Read: anytime (reserved locations read zero)
Write: anytime except DACTE is available only in special modes
1
DACWAI
0
0
DACOE
0
Table 7-2. DACC0 Field Descriptions
Field
7
DACE
6
DACTE
3
DJM
2
DSGN
1
DACWAI
0
DACOE
Description
DAC Enable — This bit enables digital-to-analog converter functionality. When enabled, an analog voltage
based on the digital value in the DAC data register will be output. When disabled, DAO pin is high-impedance.
0 DAC is disabled and powered down
1 DAC is enabled for conversion
DAC Test Enable — This reserved bit is designed for factory test purposes only and is not intended for general
user access. Writing to this bit when in special test modes can alter DAC functionality.
Data Register Data Justification — This bit controls the justification of the data in the DAC data register
(DACD). If DJM is clear (left-justified), the data to be converted must be written to left justified DACD and the right
justified DACD register will read zeroes. If DJM is set (right-justified), the data to be converted is written to right
justified DACD register and left justified DACD register reads zeroes. Data is preserved if DJM bit is changed
after data is written.
0 Left justified data in DAC data register
1 Right justified data in DAC data register
Data Register Signed — This bit selects between signed and unsigned conversion data representation in the
DAC data register. Signed data is represented as 2’s complement.
0 Unsigned data representation in DAC data register
1 Signed data representation in DAC data register
DAC Stop in WAIT Mode — DACWAI disables the DAC8B1C module (no new conversion is done) during wait
mode.
0 DAC is enabled during wait mode
1 DAC is disabled and powered down during wait mode
DAC Output Enable — This bit enables the output on the DAO pin. To output the DAC voltage, the DACOE bit
and the DACE bit must be set. When disabled, DAO pin is high-impedance.
0 Output is not available for external use
1 Output on DAO pin enabled.
MC9S12E128 Data Sheet, Rev. 1.07
240
Freescale Semiconductor