PIC16F872-I/SS Microchip Technology, PIC16F872-I/SS Datasheet - Page 434

• Manufacturer Part Number: PIC16F872-I/SS
• Description: IC MCU FLASH 2KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F872-I/SS

• Core Size: 8-Bit
• Program Memory Size: 3.5KB (2K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 64 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 64Byte
• Ram Memory Size: 128Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C, SPI, SSP
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3 bit
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details

PICmicro MID-RANGE MCU FAMILY
23.7.1
DS31023A-page 23-12
Faster Conversion - Lower Resolution Trade-off
Not all applications require a result with 10-bits of resolution, but may instead require a faster
conversion time. The A/D module allows users to make the trade-off of conversion speed to res-
olution. Regardless of the resolution required, the acquisition time is the same. To speed up the
conversion, the clock source of the A/D module may be switched so that the T
the minimum specified time (see the applicable electrical specification). Once the T
lates the minimum specified time, all the following A/D result bits are not valid (see A/D Conver-
sion Timing in the Electrical Specifications section). The clock sources may only be switched
between the three oscillator versions (cannot be switched from/to RC). The equation to deter-
mine the time before the oscillator can be switched is as follows:
Since the T
ware loop, etc.) to determine when the A/D oscillator may be changed.
comparison of time required for a conversion with 4-bits of resolution, versus the 10-bit resolution
conversion. The example is for devices operating at 20 MHz (The A/D clock is programmed for
32T
The 2T
values.
Example 23-4:
Note 1: A minimum T
T
T
2T
AD
OSC
Conversion time
Where: N
OSC
AD
2: If the full 8-bit conversion is required, the A/D clock source should not be changed.
OSC
+ N • T
), and assumes that immediately after 6T
AD
violates the minimum T
AD
is based from the device oscillator, the user must use some method (a timer, soft-
+ (11 - N)(2T
4-bit vs. 8-bit Conversion Times
= T
= number of bits of resolution required.
AD
time of 1.6 s is required.
AD
Preliminary
+ N • T
OSC
)
AD
AD
time since the last 4 bits will not be converted to correct
+ (11 - N)(2T
(MHz)
Freq.
20
20
20
AD
, the A/D clock is programmed for 2T
(1)
OSC
)
1.6 s
8.7 s
50 ns
4-bit
1997 Microchip Technology Inc.
Resolution
Example 23-4
AD
17.6 s
time violates
10-bit
1.6 s
50 ns
AD
time vio-
shows a
OSC
.