Operation Of The 8/10-Bit A/D Converter - Fujitsu MB91150 Series Hardware Manual

CHAPTER 13 8/10-BIT A/D CONVERTER

13.6 Operation of the 8/10-bit A/D Converter

The 8/10-bit A/D converter supports three modes: single-conversion mode,
continuous-conversion mode, or intermittent-conversion mode. This section describes
the operation of the converter in each mode.
I Operation in single-conversion mode
In single-conversion mode, analog inputs from channels specified by the ANS bits and ANE bits
are converted in sequence. After conversion is done for the end channel specified by the ANE
bits, A/D conversion ends. When the start channel is the same as the end channel (ANS =
ANE), conversion is performed only for the channel specified by the ANS bits. To operate the
converter in single-conversion mode, the setting shown in Figure 13.6-1 "Single-conversion
mode setting" is required.
bit15 bit14
ADCS
BUSY INT
ADCR S10 ST1 ST0 CT1 CT0
AICK
Note:
The following shows examples for the conversion sequences in single-conversion mode.
ANS = 000
ANS = 110
ANS = 011
I Operation in continuous-conversion mode
In the continuous-conversion mode, analog inputs from channels specified by the ANS bits and
ANE bits are converted in sequence. After conversion is done for the end channel specified by
the ANE bits, A/D conversion control returns to the analog input channel specified by the ANS
bits, before A/D conversion for the channel continues. When the start channel is same as the
end channel (ANS = ANE), conversion is repeatedly performed only for the channel specified by
the ANS bits. To operate the converter in continuous-conversion mode, the setting shown in
Figure 13.6-2 "Continuous-conversion mode setting" is required.
290
Figure 13.6-1 Single-conversion mode setting
bit13 bit12 bit11 bit10 bit9 bit8 bit7
Re-
INTE PAUS STS1 STS0 STRT
served
, ANE = 011 : AN0 --> AN1 --> AN2 --> AN3 --> End
B B
, ANE = 010 : AN6 --> AN7 --> AN0 --> AN1 --> AN2 --> End
B B
, ANE = 011 : AN3 --> End
B B
bit6 bit5 bit4 bit3
MD1 MD0 ANS2 ANS1 ANS0
0
Stores converted data.
: Used bit
: Set the bit corresponding to the used pin to 1.
: Set 0.
0
bit2 bit1 bit0
ANE2 ANE1 ANE0