PIC16F818-I/P Microchip Technology, PIC16F818-I/P Datasheet - Page 513

• 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

1997 Microchip Technology Inc.
The total capacitance on the programming pins affects the rise rates of these signals as they are
driven out of the programmer. Typical circuits use several hundred microfarads of capacitance on
V
driver in the programmer to meet the rise rate timings for V
to simply program the PICmicro itself and don’t have strong enough drivers to power the appli-
cation circuit. One solution is to use a driver board between the programmer and the application
circuit. The driver board requires a separate power supply that is capable of driving the V
V
cation circuit. RB6 and RB7 are not buffered on this schematic but may require buffering depend-
ing upon the application. A sample driver board schematic is shown in
The Microchip programming specification states that the device should be programmed at 5V.
Special considerations must be made if your application circuit operates at 3V only. These con-
siderations may include totally isolating the PICmicro during programming. The other issue is that
the device must be verified at the minimum and maximum voltages at which the application circuit
will be operating. For instance, a battery operated system may operate from three 1.5V cells giv-
ing an operating voltage range of 2.7V to 4.5V. The programmer must program the device at 5V
and must verify the program memory contents at both 2.7V and 4.5V to ensure that proper pro-
gramming margins have been achieved. This ensures the PICmicro operation over the voltage
range of the system.
The final issue deals with the oscillator circuit on the application board. The voltage on
MCLR/V
code. The crystal modes available on the PICmicro are not affected by this issue because the
Oscillator Start-up Timer waits for 1024 oscillations before any code is executed. However, RC
oscillators do not require any start-up time and, therefore, the Oscillator Start-up Timer is not
used. The programmer must drive MCLR/V
oscillator toggles four times. If the RC oscillator toggles four or more times, the program counter
will be incremented to some value X. Now when the device enters programming mode, the pro-
gram counter will not be zero and the programmer will start programming your code at an offset
of X. There are several alternatives that can compensate for a slow rise rate on MCLR/V
first method would be to not populate the R, program the device, and then insert the R. The other
method would be to have the programming interface drive the OSC1 pin of the PICmicro to
ground while programming. This will prevent any oscillations from occurring during programming.
Now all that is left is how to connect the application circuit to the programmer. This depends a lot
on the programming environment and will be discussed in that section.
DD
DD
Note:
which helps to dampen noise and ripple. However, this capacitance requires a fairly strong
pins with the correct rise rates and should also provide enough current to power the appli-
PP
must rise to the specified program mode entry voltage before the device executes any
The driver board design MUST be tested in the user's application to determine the
effects of the application circuit on the programming signals timing. Changes may
be required if the application places a significant load on V
PP
to the program mode entry voltage before the RC
Section 28. ICSP
DD
. Most programmers are designed
DD
Figure
, V
PP
DS31028A-page 28-5
28-2.
, RB6
OR
RB7.
PP
PP
. The
and
28