PIC16C781T-I/SO Microchip Technology, PIC16C781T-I/SO Datasheet - Page 74

• Manufacturer Part Number: PIC16C781T-I/SO
• Description: IC MCU CMOS 8BIT 1K 20MHZ 20SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16C781T-I/SO

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 13
• Program Memory Size: 1.75KB (1K x 14)
• Program Memory Type: OTP
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x8b; D/A 1x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SOIC (7.5mm Width)
• For Use With: AC164028 - MODULE SKT PROMATEII 20SOIC/DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -
• Other names: PIC16C781TI/SO

PIC16C781/782
9.2
9.2.1
The ANSEL and TRISB registers control the operation
of the ADC port pins. The port pins to be used as ana-
log inputs must have their corresponding TRISB bits
set (= 1). The proper ANSEL bits must also be set (ana-
log input) to disable the digital input buffer.
TABLE 9-1:
Legend: Shaded cells are outside of recommended range.
Note 1: The RC source has a typical T
DS41171A-page 72
2 T
8 T
32 T
RC
Note 1: The ADC operation is independent of the
OSC
OSC
Operation
OSC
2: These values violate the minimum required T
3: For faster conversion times, the selection of another clock source is recommended.
4: When device frequency is greater than 1 MHz, the RC ADC conversion clock source is recommended for
Configuring the ADC Module
ADC Clock Source (T
2: When reading the PORTA or PORTB reg-
3: Analog levels on any pin that is defined as
SLEEP operation only.
CONFIGURING ANALOG PORT
PINS
state of the TRISB or ANSEL bits. These
bits must be configured by the firmware
prior to initiation of an ADC conversion.
isters, all pins configured as analog input
channels will read as a ‘0’.
a digital input, including AN<7:0>, may
cause the input buffer to consume excess
supply current.
TAD vs. DEVICE OPERATING FREQUENCIES: PIC16C781/782
ADCS1:ADCS0
00
01
10
11
AD
)
AD
time of 4 s.
2 - 6 s
100 ns
20 MHz
400 ns
1.6 s
Preliminary
(1,4)
(2)
AD
time.
9.2.2
The VCFG<5:4> bits in the ADCON1 register configure
the ADC module reference voltage input, ADC
reference input can come from any of the following:
• Internal voltage reference (V
• External comparator C1 reference (V
• DAC output (V
• Analog positive supply (A
If an external reference is chosen for the ADC
the port pin that multiplexes with the incoming external
reference must also be configured as an analog input.
9.2.3
The ADC conversion cycle requires 9.5T
of the ADC conversion clock is software selectable.
The four possible options for ADC clock are:
• F
• F
• F
• ADRC (clock derived from a dedicated internal
For correct ADC conversion, the ADC conversion clock
(T
of 1.6 sec. Table 9-1 shows the resultant T
derived from the device operating frequencies and the
ADC clock source selected.
2 - 6 s
400 ns
AD
RC oscillator)
5 MHz
1.6 s
6.4 s
OSC
OSC
OSC
) must be selected to ensure a minimum T
/2
/8
/32
Device Frequency
(1,4)
(2)
CONFIGURING THE REFERENCE
VOLTAGES
SELECTING THE ADC
CONVERSION CLOCK
DAC
2 - 6 s
1.25 MHz
25.6 s
)
6.4 s
1.6 s
2001 Microchip Technology Inc.
(1,4)
(3)
VDD
R
)
)
333.33kHz
2 - 6 s
REF
24 s
96 s
AD
6 s
. The source
1)
REF
(3)
(3)
AD
REF
(1)
AD
input,
times
. The
time