Datasheet

 1997-2013 Microchip Technology Inc. DS30561C-page 45
PIC12C67X
REGISTER 8-1: ADCON0 REGISTER (ADDRESS 1Fh)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
ADCS1 ADCS0
reserved CHS1 CHS0 GO/DONE reserved ADON R = Readable bit
W = Writable bit
U = Unimplemented bit,
read as ‘0’
- n = Value at POR reset
bit7 bit0
bit 7-6: ADCS<1:0>: A/D Conversion Clock Select bits
00 = F
OSC/2
01 = F
OSC/8
10 = F
OSC/32
11 = F
RC (clock derived from an RC oscillation)
bit 5: Reserved
bit 4-3: CHS<1:0>: Analog Channel Select bits
00 = channel 0, (GP0/AN0)
01 = channel 1, (GP1/AN1)
10 = channel 2, (GP2/AN2)
11 = channel 3, (GP4/AN3)
bit 2: GO/DONE
: A/D Conversion Status bit
If ADON = 1
1 = A/D conversion in progress (setting this bit starts the A/D conversion)
0 = A/D conversion not in progress (this bit is automatically cleared by hardware when the A/D conversion
is complete)
bit 1: Reserved
bit 0: ADON: A/D on bit
1 = A/D converter module is operating
0 = A/D converter module is shut off and consumes no operating current
8.0 ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The Analog-To-Digital (A/D) converter module has four
analog inputs.
The A/D allows conversion of an analog input signal to
a corresponding 8-bit digital number (refer to Applica-
tion Note AN546 for use of A/D Converter). The output
of the sample and hold is the input into the converter,
which generates the result via successive approxima-
tion. The analog reference voltage is software select-
able to either the device’s positive supply voltage (V
DD)
or the voltage level on the GP1/AN1/V
REF pin. The A/D
converter has a unique feature of being able to operate
while the device is in SLEEP mode.
The A/D module has three registers. These registers
are:
• A/D Result Register (ADRES)
• A/D Control Register 0 (ADCON0)
• A/D Control Register 1 (ADCON1)
The ADCON0 Register, shown in Figure 8-1, controls
the operation of the A/D module. The ADCON1 Regis-
ter, shown in Figure 8-2, configures the functions of the
port pins. The port pins can be configured as analog
inputs (GP1 can also be a voltage reference) or as dig-
ital I/O.
Note 1: If the port pins are configured as analog
inputs (reset condition), reading the port
(MOVF GPIO,W) results in reading '0's.
2: Changing ADCON1 Register can cause
the GPIF and INTF flags to be set in the
INTCON Register. These interrupts
should be disabled prior to modifying
ADCON1.