PIC16F872_06 Datasheet, PDF (87/168 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS Flash Microcontroller with 10-Bit A/D

PIC16F872
10.5 A/D Operation During SLEEP
The A/D module can operate during SLEEP mode. This
requires that the A/D clock source be set to RC
(ADCS1:ADCS0 = 11). When the RC clock source is
selected, the A/D module waits one instruction cycle
before starting the conversion. This allows the SLEEP
instruction to be executed, which eliminates all digital
switching noise from the conversion. When the conver-
sion is completed, the GO/DONE bit will be cleared and
the result loaded into the ADRES register. If the A/D
interrupt is enabled, the device will wake-up from
SLEEP. If the A/D interrupt is not enabled, the A/D mod-
ule will then be turned off, although the ADON bit will
remain set.
When the A/D clock source is another clock option (not
RC), a SLEEP instruction will cause the present conver-
sion to be aborted and the A/D module to be turned off,
though the ADON bit will remain set.
Turning off the A/D places the A/D module in its lowest
current consumption state.
Note:
For the A/D module to operate in SLEEP,
the A/D clock source must be set to RC
(ADCS1:ADCS0 = 11). To allow the con-
version to occur during SLEEP, ensure the
SLEEP instruction immediately follows the
instruction that sets the GO/DONE bit.
10.6 Effects of a RESET
A device RESET forces all registers to their RESET
state. This forces the A/D module to be turned off, and
any conversion is aborted. All A/D input pins are con-
figured as analog inputs.
The value that is in the ADRESH:ADRESL registers is
not modified for a Power-on Reset. The
ADRESH:ADRESL registers will contain unknown data
after a Power-on Reset.
TABLE 10-2: REGISTERS/BITS ASSOCIATED WITH A/D
Address Name Bit 7 Bit 6 Bit 5
Bit 4
Bit 3
Bit 2
Bit 1 Bit 0
POR,
BOR
MCLR,
WDT
0Bh,8Bh, INTCON GIE PEIE TMR0IE INTE
10Bh, 18Bh
RBIE TMR0IF INTF RBIF 0000 000x 0000 000u
0Ch
PIR1
(1) ADIF (1)
(1)
SSPIF CCP1IF TMR2IF TMR1IF r0rr 0000 0000 0000
8Ch
PIE1
(1) ADIE (1)
(1)
SSPIE CCP1IE TMR2IE TMR1IE r0rr 0000 0000 0000
1Eh
ADRESH A/D Result Register High Byte
xxxx xxxx uuuu uuuu
9Eh
ADRESL A/D Result Register Low Byte
xxxx xxxx uuuu uuuu
1Fh
ADCON0 ADCS1 ADCS0 CHS2 CHS1 CHS0 GO/DONE — ADON 0000 00-0 0000 00-0
9Fh
ADCON1 ADFM —
—
—
PCFG3 PCFG2 PCFG1 PCFG0 --0- 0000 --0- 0000
85h
TRISA
—
— PORTA Data Direction Register
--11 1111 --11 1111
05h
PORTA
—
— PORTA Data Latch when written: PORTA pins when read
--0x 0000 --0u 0000
Legend: x = unknown, u = unchanged, - = unimplemented, read as '0'. Shaded cells are not used for A/D conversion.
Note 1: These bits are reserved; always maintain clear.
© 2006 Microchip Technology Inc.
DS30221C-page 85