PIC16F54-I/SS Microchip Technology, PIC16F54-I/SS Datasheet - Page 27

• Manufacturer Part Number: PIC16F54-I/SS
• Description: IC MCU FLASH 512X12 20SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F54-I/SS

• Core Size: 8-Bit
• Program Memory Size: 768B (512 x 12)
• Core Processor: PIC
• Speed: 20MHz
• Peripherals: POR, WDT
• Number Of I /o: 12
• Program Memory Type: FLASH
• Ram Size: 25 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 12
• Ram Memory Size: 25Byte
• Cpu Speed: 20MHz
• No. Of Timers: 1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164014 - MODULE SKT PROMATEII 44PQFP
• Eeprom Size: -
• Data Converters: -
• Connectivity: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

5.1
The PIC16F5X Family incorporates on-chip Power-on
Reset (POR) circuitry which provides an internal chip
Reset for most power-up situations. To use this feature,
the user merely ties the MCLR/V
simplified block diagram of the on-chip Power-on Reset
circuit is shown in Figure 5-1.
The Power-on Reset circuit and the Device Reset Timer
(Section 5.2) circuit are closely related. On power-up,
the Reset latch is set and the DRT is reset. The DRT
timer begins counting once it detects MCLR to be high.
After the time-out period, which is typically 18 ms, it will
reset the Reset latch and thus end the on-chip Reset
signal.
A power-up example where MCLR is not tied to V
shown in Figure 5-3. V
before bringing MCLR high. The chip will actually come
out of Reset T
In Figure 5-4, the on-chip Power-on Reset feature is
being used (MCLR and V
is stable before the start-up timer times out and there is
no problem in getting a proper Reset. However,
Figure 5-5 depicts a problem situation where V
too slowly. The time between when the DRT senses a
high on the MCLR/V
pin (and V
In this situation, when the start-up timer times out, V
has not reached the V
therefore, not ensured to function correctly. For such
situations, we recommend that external RC circuits be
used to achieve longer POR delay times (Figure 5-2).
For more information on PIC16F5X POR, see
Application Note AN522, “Power-Up Considerations”
at www.microchip.com.
The POR circuit does not produce an internal Reset
when V
 2004 Microchip Technology Inc.
Note:
DD
Power-on Reset (POR)
DD
declines.
When the device starts normal operation
(exits
operating parameters (voltage, frequency,
temperature, etc.) must be met to ensure
operation. If these conditions are not met,
the device must be held in Reset until the
operating conditions are met.
) actually reach their full value, is too long.
DRT
msec after MCLR goes high.
the
PP
DD
DD
pin, and when the MCLR/V
DD
is allowed to rise and stabilize
Reset
(min) value and the chip is,
are tied together). The V
condition),
PP
pin to V
DD
device
DD
DD
rises
Preliminary
. A
DD
DD
PP
is
FIGURE 5-2:
• External Power-on Reset circuit is required
• R < 40 k is recommended to make sure that
• R1 = 100
only if V
helps discharge the capacitor quickly when
V
voltage drop across R does not violate the
device electrical specification.
flowing into MCLR from external capacitor C
in the event of MCLR pin breakdown due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS).
DD
V
DD
powers down.
D
DD
V
power-up is too slow. The diode D
to 1 k will limit any current
DD
R
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW V
C
R1
PIC16F5X
DD
POWER-UP)
MCLR
DS41213B-page 25
PIC16F5X