SD16_A Operation
22-10 SD16_A
22.2.8 Conversion Memory Register: SD16MEM0

The SD16MEM0 register is associated with the SD16_A channel. Conversion

results are moved to the SD16MEM0 register with each decimation step of the

digital filter. The SD16IFG bit is set when new data is written to SD16MEM0.

SD16IFG is automatically cleared when SD16MEM0 is read by the CPU or

may be cleared with software.

Output Data Format

The output data format is configurable in twos complement, offset binary or

unipolar mode as shown in Table 222.The data format is selected by the

SD16DF and SD16UNI bits.

Table 222.Data Format
SD16UNI SD16DF Format Analog Input SD16MEM0Digital Filter Output
(OSR =256)
+FSR FFFF FFFFFF
00
Bipolar
Offset ZERO 8000 800000
00
Offset
Binary FSR 0000 000000
+FSR 7FFF 7FFFFF
01
Bipolar
TwosZERO 0000 000000
01
Twos
compliment FSR 8000 800000
+FSR FFFF FFFFFF
1 X Unipolar ZERO 0000 800000
1 X Unipolar
FSR 0000 000000
Independent of SD16OSRx and SD16XOSR settings; SD16LSBACC = 0.

Figure 225 shows the relationship between the full-scale input voltage range

from VFSR to +VFSR and the conversion result. The data formats are

illustrated.

Figure 225. Input Voltage vs. Digital Output
Input
Voltage
SD16MEMx
VFSR
+VFSR
7FFFh
8000h
Bipolar Output: 2s complement
Input
Voltage
SD16MEMx
VFSR +VFSR
FFFFh
8000h
Bipolar Output: Offset Binary
0000h
0000h
Input
Voltage
SD16MEMx
VFSR +VFSR
FFFFh
Unipolar Output
0000h