PIC18F258 MICROCHIP [Microchip Technology], PIC18F258 Datasheet - Page 355

• Manufacturer Part Number: PIC18F258
• Description: High Performance, 28/40-Pin Enhanced FLASH Microcontrollers with CAN
• Manufacturer: MICROCHIP [Microchip Technology]

FIGURE 27-22:
TABLE 27-24: A/D CONVERSION REQUIREMENTS
130
131
132
135
136
Note 1: ADRES register may be read on the following T
Param
2002 Microchip Technology Inc.
No.
Note
2: See Section 20.0 for minimum conditions when input voltage has changed more than 1 LSb.
3: The time for the holding capacitor to acquire the “New” input voltage when the voltage changes full scale
4: On the next Q4 cycle of the device clock.
5: The time of the A/D clock period is dependent on the device frequency and the T
A/D DATA
SAMPLE
A/D CLK
T
T
T
T
T
ADRES
Symbol
BSF ADCON0, GO
AD
CNV
ACQ
SWC
AMP
after the conversion (AV
is 50 .
1:
2:
ADIF
GO
Q4
If the A/D clock source is selected as RC, a time of T
This allows the SLEEP instruction to be executed.
This is a minimal RC delay (typically 100 ns), which also disconnects the holding capacitor from the analog input.
A/D clock period
Conversion time
(not including acquisition time) (Note 1)
Acquisition time (Note 3)
Switching time from convert
Amplifier settling time (Note 2)
132
A/D CONVERSION TIMING
(Note 2)
Characteristic
DD
9
to AV
PIC18FXX8
PIC18LFXX8
PIC18FXX8
PIC18LFXX8
SS
8
, or AV
OLD_DATA
sample
7
Preliminary
SS
. . .
CY
to AV
SAMPLING STOPPED
CY
is added before the A/D clock starts.
DD
cycle.
. . .
131
130
). The source impedance (R
Min
1.6
3.0
2.0
3.0
11
15
10
—
1
2
(Note 4)
20
20
Max
6.0
9.0
12
—
—
—
(5)
(5)
1
Units
T
AD
s
s
s
s
s
s
s
0
PIC18FXX8
T
T
A/D RC mode
A/D RC mode
-40 C
0 C
This may be used if the
“new” input voltage has not
changed by more than 1 LSb
(i.e., 5 mV @ 5.12V) from the
last sampled voltage (as
stated on C
OSC
OSC
AD
S
) on the input channels
clock divider.
based, V
based, V
Temp
NEW_DATA
DONE
Temp
Conditions
DS41159B-page 353
HOLD
T
+125 C
REF
REF
CY
+125 C
).
full range
3.0V