
2001 Microchip Technology Inc.
DS30292C-page 175
PIC16F87X
FIGURE 15-21:
A/D CONVERSION TIMING
TABLE 15-13: A/D CONVERSION REQUIREMENTS
131
130
132
BSF ADCON0, GO
Q4
A/D CLK
A/D DATA
ADRES
ADIF
GO
SAMPLE
OLD_DATA
SAMPLING STOPPED
DONE
NEW_DATA
(TOSC/2)(1)
98
7
2
1
0
Note: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP
instruction to be executed.
1 TCY
. . .
Param
No.
Sym
Characteristic
Min
Typ
Max
Units
Conditions
130
TAD
A/D clock period
Standard(F)1.6
——
sTOSC based, VREF ≥ 3.0V
Extended(LF)3.0
——
sTOSC based, VREF ≥ 2.0V
Standard(F)
2.0
4.0
6.0
s
A/D RC mode
Extended(LF)
3.0
6.0
9.0
s
A/D RC mode
131
TCNV Conversion time (not including S/H time)
(Note 1)
—
12
TAD
132
TACQ Acquisition time
(Note 2)
10*
40
—
s
The minimum time is the
amplifier settling time. This may
be used if the "new" input volt-
age has not changed by more
than 1 LSb (i.e., 20.0 mV @
5.12V) from the last sampled
voltage (as stated on CHOLD).
134
TGO
Q4 to A/D clock start
—
TOSC/2 §—
—
If the A/D clock source is
selected as RC, a time of TCY is
added before the A/D clock
starts. This allows the SLEEP
instruction to be executed.
*
These parameters are characterized but not tested.
Data in "Typ" column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance only and are
not tested.
§
This specification ensured by design.
Note 1: ADRES register may be read on the following TCY cycle.