PIC16F818-I/P Microchip Technology, PIC16F818-I/P Datasheet - Page 396

• Manufacturer Part Number: PIC16F818-I/P
• Description: IC MCU FLASH 1KX14 18-DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F818-I/P

• Program Memory Type: FLASH
• Program Memory Size: 1.75KB (1K x 14)
• Package / Case: 18-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• 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: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ACICE0202 - ADAPTER MPLABICE 18P 300 MILAC164010 - MODULE SKT PROMATEII DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
21.7.1
21.8
DS31021A-page 21-12
Faster Conversion - Lower Resolution Trade-off
A/D Operation During Sleep
Not all applications require a result with 8-bits of resolution, but may instead require a faster con-
version time. The A/D module allows users to make the trade-off of conversion speed to resolu-
tion. 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 8-bit resolution
conversion. The example is for devices operating at 20 MHz (The A/D clock is programmed for
32T
The 2T
values.
Example 21-3:
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 internal digital switching noise from the conversion. When the conversion 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 module will then be turned off (to conserve power), 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 conversion 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 1: A minimum T
T
T
T
AD
OSC
AD
Note:
Conversion time =
Where: N
OSC
+ N • T
2: If the full 8-bit conversion is required, the A/D clock source should not be changed.
OSC
), and assumes that immediately after 5T
AD
violates the minimum T
For the A/D module to operate in SLEEP, the A/D clock source must be set to RC
(ADCS1:ADCS0 = 11). To perform an A/D conversion in SLEEP, the GO/DONE bit
must be set, followed by the SLEEP instruction.
AD
is based from the device oscillator, the user must use some method (a timer, soft-
+ (10 - N)(2T
4-bit vs. 8-bit Conversion Times
=
AD
time of 1.6 s is required.
T
number of bits of resolution required.
AD
OSC
+ N • T
)
AD
AD
time since the last 4-bits will not be converted to correct
+ (10 - N)(2T
(MHz)
Freq.
20
20
20
AD
, the A/D clock is programmed for 2T
(1)
OSC
)
1.6 s
8.6 s
50 ns
4-bit
1997 Microchip Technology Inc.
Resolution
Example 21-3
AD
17.6 s
time violates
1.6 s
50 ns
8-bit
AD
time vio-
shows a
OSC
.