PIC16F946T-I/PT Microchip Technology, PIC16F946T-I/PT Datasheet - Page 152

• Manufacturer Part Number: PIC16F946T-I/PT
• Description: Microcontroller
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F946T-I/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 14KB (8K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 336 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-TFQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: MA160011 - DAUGHTER BOARD PICDEM LCD 16F91X
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

PIC16F946
12.1
There are three registers available to control the
functionality of the A/D module:
1.
2.
3.
12.1.1
The ANS<7:0> bits (ANSEL<7:0>) and the TRIS bits
control the operation of the A/D port pins. Set the
corresponding TRIS bits to set the pin output driver to
its high-impedance state. Likewise, set the correspond-
ing ANSEL bit to disable the digital input buffer.
12.1.2
There are up to eight analog channels on the PIC16F946,
AN<7:0>. The CHS<2:0> bits (ADCON0<4:2>) control
which channel is connected to the sample and hold
circuit.
12.1.3
There are two options for each reference to the A/D
converter, V
either V
V
applied voltage. VCFG<1:0> bits are used to select the
reference source.
TABLE 12-1:
DS41265A-page 150
Legend: Shaded cells are outside of recommended range.
Note 1:
REF
Note:
Operation
16 T
32 T
64 T
A/D RC
ANSEL (Register 12-1)
ADCON0 (Register 12-2)
ADCON1 (Register 12-3)
2 T
4 T
8 T
- can be connected to either V
A/D Clock Source (T
2:
3:
4:
DD
OSC
OSC
OSC
OSC
OSC
OSC
A/D Configuration and Operation
or an externally applied voltage. Alternatively,
REF
The A/D RC source has a typical T
These values violate the minimum required T
For faster conversion times, the selection of another clock source is recommended.
When the device frequency is greater than 1 MHz, the A/D RC clock source is only recommended if the
conversion will be performed during Sleep.
ANALOG PORT PINS
Analog voltages on any pin that is defined
as a digital input may cause the input
buffer to conduct excess current.
CHANNEL SELECTION
VOLTAGE REFERENCE
+ and V
T
AD
ADCS<2:0>
REF
vs. DEVICE OPERATING FREQUENCIES
000
100
001
101
010
110
x11
-. V
AD
REF
)
+ can be connected to
SS
or an externally
2-6 s
100 ns
200 ns
400 ns
800 ns
20 MHz
1.6 s
3.2 s
AD
(1,4)
(2)
(2)
(2)
(2)
time of 4 s for V
Preliminary
AD
time.
2-6 s
12.8 s
400 ns
800 ns
12.1.4
The A/D conversion cycle requires 11 T
of the conversion clock is software selectable via the
ADCS bits (ADCON1<6:4>). There are seven possible
clock options:
• F
• F
• F
• F
• F
• F
• F
For correct conversion, the A/D conversion clock
(1/T
1.6 s. Table 12-1 shows a few T
selected frequencies.
5 MHz
1.6 s
3.2 s
6.4 s
DD
OSC
OSC
OSC
OSC
OSC
OSC
RC
AD
Device Frequency
(1,4)
(2)
(2)
(3)
) must be selected to ensure a minimum T
> 3.0V.
(dedicated internal oscillator)
/2
/4
/8
/16
/32
/64
CONVERSION CLOCK
2-6 s
16.0 s
500 ns
1.0 s
8.0 s
4 MHz
2.0 s
4.0 s
© 2005 Microchip Technology Inc.
(1,4)
(2)
(3)
(2)
(3)
AD
calculations for
AD
2-6 s
1.25 MHz
12.8 s
25.6 s
51.2 s
1.6 s
3.2 s
6.4 s
. The source
(1,4)
(3)
(3)
(3)
AD
of