PIC18F23K20 MICROCHIP [Microchip Technology], PIC18F23K20 Datasheet - Page 268

• Manufacturer Part Number: PIC18F23K20
• Description: 28/40/44-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F2XK20/4XK20
19.2
19.2.1
To enable the ADC module, the ADON bit of the
ADCON0 register must be set to a ‘1’. Setting the GO/
DONE bit of the ADCON0 register to a ‘1’ will, depend-
ing on the ACQT bits of the ADCON2 register, either
immediately start the Analog-to-Digital conversion or
start an acquisition delay followed by the Analog-to-
Digital conversion.
FIGURE 19-3:
FIGURE 19-4:
DS41303G-page 268
(Holding capacitor continues
acquiring input)
Set GO bit
1
T
CY
Set GO bit
T
ADC Operation
Holding capacitor is disconnected from analog input (typically 100 ns)
ACQT
Acquisition
Automatic
- T
STARTING A CONVERSION
2
Time
AD
Conversion starts
Cycles
T
AD
3
1 T
A/D CONVERSION T
A/D CONVERSION T
AD
b9
4
2 T
(Holding capacitor is disconnected from analog input)
Conversion starts
AD
b8
1
3 T
b9
AD
2
b7
4 T
On the following cycle:
ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
AD
b8
3
b6
AD
AD
5 T
On the following cycle:
ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
CYCLES (A
CYCLES (A
AD
b5
b7
4
6 T
T
AD
b4
5
b6
AD
7 T
Cycles
Figure 19-3 shows the operation of the A/D converter
after the GO bit has been set and the ACQT<2:0> bits
are cleared. A conversion is started after the following
instruction to allow entry into SLEEP mode before the
conversion begins.
Figure 19-4 shows the operation of the A/D converter
after the GO bit has been set and the ACQT<2:0> bits
are set to ‘010’ which selects a 4 T
before the conversion starts.
CQT
AD
CQT
b3
b5
Note:
6
8
<2:0> = 000, T
<2:0> = 010, T
T
AD
b4
b2
7
9 T
The GO/DONE bit should not be set in the
same instruction that turns on the ADC.
Refer to Section 19.2.9 “A/D Conver-
sion Procedure”.
AD
b3
8
b1
10
T
AD
ACQ
b0
b2
9
ACQ
 2010 Microchip Technology Inc.
11
2 T
= 0)
10
= 4 T
Discharge
b1
AD
AD
AD
b0
11
)
acquisition time
2 T
Discharge
AD