Datasheet

Table Of Contents
2011-2013 Microchip Technology Inc. DS40001609C-page 137
PIC16(L)F1508/9
TABLE 15-1: ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES
FIGURE 15-2: ANALOG-TO-DIGITAL CONVERSION T
AD CYCLES
ADC Clock Period (TAD) Device Frequency (FOSC)
ADC
Clock
Source
ADCS<2:0
>
20 MHz 16 MHz 8 MHz 4 MHz 1 MHz
Fosc/2 000
100 ns 125 ns 250 ns 500 ns 2.0 s
Fosc/4 100
200 ns 250 ns 500 ns 1.0 s4.0 s
Fosc/8 001 400 ns 500 ns 1.0 s2.0 s 8.0 s
Fosc/16 101 800 ns 1.0 s2.0 s4.0 s 16.0 s
Fosc/32 010 1.6 s2.0 s4.0 s
8.0 s 32.0 s
Fosc/64 110 3.2 s4.0 s 8.0 s 16.0 s 64.0 s
FRC x11 1.0-6.0 s 1.0-6.0 s 1.0-6.0 s 1.0-6.0 s 1.0-6.0 s
Legend: Shaded cells are outside of recommended range.
Note: The T
AD period when using the FRC clock source can fall within a specified range, (see TAD parameter).
The T
AD period when using the FOSC-based clock source can be configured for a more precise TAD period.
However, the FRC clock source must be used when conversions are to be performed with the device in
Sleep mode.
TAD1TAD2TAD3TAD4TAD5TAD6TAD7TAD8TAD9TAD10 TAD11
SetGObit
Conversion Starts
Holding capacitor disconnected
from analog input (THCD).
On the following cycle:
ADRESH:ADRESL is loaded,
GO bit is cleared,
ADIF bit is set,
holding capacitor is reconnected to analog input.
b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
Enable ADC (ADON bit)
and
Select channel (ACS bits)
THCD
TACQ
Rev. 10-000035A
7/30/2013