Operation Of The 8/10-Bit A/D Converter - Fujitsu MB90390 Series Hardware Manual

18.6

Operation of the 8/10-Bit A/D Converter

The 8/10-bit A/D converter has three conversion modes: single conversion mode,
continuous conversion mode, and stop conversion mode. This section describes
operation in each mode.
■ Operation in Single Conversion Mode
In single conversion mode, the analog inputs from the channel specified by the ANS bits to the channel
specified by the ANE bits are sequentially converted. When the channels up to the end channel specified by the
ANE bits have been converted, A/D conversion stops. If the start and end channels are the same (ANS = ANE),
just the channel specified by the ANS bits is converted.
The figure below shows the settings required for operation in single conversion mode.
bit15 bit14
ADCS
BUSY INT
✧ ✧
ADCR S10 ST1
✧ ✧
ADER
ADSEL
✧ ✦
✧ : Used during conversion.
✦ : Set the bit that corresponds to the used pin to "1".
0 : Set to "0".
Reference:
The following are sample conversion sequences in single conversion mode:
(It is assumed that ADSEL = 0.)
ANS = 000
ANS = 110
ANS = 011
Figure 18.6-1 Settings for Single Conversion Mode
bit13 bit12 bit11 bit10 bit9
INTE PAUS STS1 STS0 STRT
✧ ✧ ✧ ✧
ST0 CT1 CT0 -
✧ ✧ ✧
✦ ✦ ✦ ✦
: AN0 → AN1 → AN2 → AN3 → End
, ANE = 011
B B
: AN6 → AN7 → AN0 → AN1 → AN2 → End
, ANE = 010
B B
: AN3 → End
, ANE = 011
B B
CHAPTER 18 8/10-BIT A/D CONVERTER
bit8 bit7 bit6 bit5
RESV MD1 MD0 ANS2
✧ ✧ ✧ ✧
0
Holds the conversion data.
✦ ✦ ✦ ✦ ✦
bit4 bit3 bit2 bit1
ANS1 ANS0 ANE2 ANE1 ANE0
✧ ✧ ✧ ✧
✦ ✦ ✦ ✦
bit0
✧
✦
295