PIC18F4220-E/P Microchip Technology, PIC18F4220-E/P Datasheet - Page 251
![IC MCU FLASH 2KX16 EEPROM 40DIP](/photos/6/61/66192/150-40-dip_sml.jpg)
PIC18F4220-E/P
Manufacturer Part Number
PIC18F4220-E/P
Description
IC MCU FLASH 2KX16 EEPROM 40DIP
Manufacturer
Microchip Technology
Series
PIC® 18Fr
Datasheets
1.PIC16F616T-ISL.pdf
(8 pages)
2.PIC18F1320-ISS.pdf
(36 pages)
3.PIC18F2220-ISO.pdf
(394 pages)
4.PIC18F2220-ISO.pdf
(6 pages)
5.PIC18F2220-ISO.pdf
(6 pages)
6.PIC18F2220-ISO.pdf
(8 pages)
7.PIC18F2220-ISO.pdf
(6 pages)
8.PIC18F2220-ISO.pdf
(6 pages)
Specifications of PIC18F4220-E/P
Core Processor
PIC
Core Size
8-Bit
Speed
40MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, LVD, POR, PWM, WDT
Number Of I /o
36
Program Memory Size
4KB (2K x 16)
Program Memory Type
FLASH
Eeprom Size
256 x 8
Ram Size
512 x 8
Voltage - Supply (vcc/vdd)
4.2 V ~ 5.5 V
Data Converters
A/D 13x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 125°C
Package / Case
40-DIP (0.600", 15.24mm)
For Use With
DVA18XP400 - DEVICE ADAPTER 18F4220 PDIP 40LDACICE0206 - ADAPTER MPLABICE 40P 600 MIL
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
PIC18F4220-E/PT
Manufacturer:
Microchip Technology
Quantity:
10 000
- PIC16F616T-ISL PDF datasheet
- PIC18F1320-ISS PDF datasheet #2
- PIC18F2220-ISO PDF datasheet #3
- PIC18F2220-ISO PDF datasheet #4
- PIC18F2220-ISO PDF datasheet #5
- PIC18F2220-ISO PDF datasheet #6
- PIC18F2220-ISO PDF datasheet #7
- PIC18F2220-ISO PDF datasheet #8
- Current page: 251 of 394
- Download datasheet (7Mb)
23.4
The Fail-Safe Clock Monitor (FSCM) allows the micro-
controller to continue operation, in the event of an
external oscillator failure, by automatically switching
the system clock to the internal oscillator block. The
FSCM function is enabled by setting the Fail-Safe
Clock Monitor Enable bit, FCMEN (CONFIG1H<6>).
When FSCM is enabled, the INTRC oscillator runs at
all times to monitor clocks to peripherals and provide
an instant backup clock in the event of a clock failure.
Clock monitoring (shown in Figure 23-3) is accom-
plished by creating a sample clock signal, which is the
INTRC output divided by 64. This allows ample time
between FSCM sample clocks for a peripheral clock
edge to occur. The peripheral system clock and the
sample clock are presented as inputs to the Clock Mon-
itor latch (CM). The CM is set on the falling edge of the
system clock source but cleared on the rising edge of
the sample clock.
FIGURE 23-3:
Clock failure is tested on the falling edge of the sample
clock. If a sample clock falling edge occurs while CM is
still set, a clock failure has been detected (Figure 23-4).
This causes the following:
• The FSCM generates an oscillator fail interrupt by
• The system clock source is switched to the
• The WDT is reset
Since the postscaler frequency from the internal oscil-
lator block may not be sufficiently stable, it may be
desirable to select another clock configuration and
enter an alternate power-managed mode (see
Section 23.3.1 “Special Considerations for Using
Two-Speed Start-up” and Section 3.1.3 “Multiple
Sleep Commands” for more details). This can be
done to attempt a partial recovery or execute a
controlled shutdown.
© 2007 Microchip Technology Inc.
Peripheral
setting bit, OSCFIF (PIR2<7>)
internal oscillator block (OSCCON is not updated
to show the current clock source – this is the
fail-safe condition)
(32 μs)
Source
INTRC
Clock
Fail-Safe Clock Monitor
(2.048 ms)
488 Hz
÷ 64
FSCM BLOCK DIAGRAM
(edge-triggered)
Clock Monitor
Latch (CM)
C
S
Q
Q
Detected
PIC18F2220/2320/4220/4320
Failure
Clock
To use a higher clock speed on wake-up, the INTOSC
or postscaler clock sources can be selected to provide
a higher clock speed by setting bits IFRC2:IFRC0
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting IFRC2:IFRC0 prior to entering Sleep mode.
Adjustments to the internal oscillator block using the
OSCTUNE register also affect the period of the FSCM
by the same factor. This can usually be neglected, as
the clock frequency being monitored is generally much
higher than the sample clock frequency.
The FSCM will detect failures of the primary or second-
ary clock sources only. If the internal oscillator block
fails, no failure would be detected, nor would any action
be possible.
23.4.1
Both the FSCM and the WDT are clocked by the
INTRC oscillator. Since the WDT operates with a sep-
arate divider and counter, disabling the WDT has no
effect on the operation of the INTRC oscillator when the
FSCM is enabled.
As already noted, the clock source is switched to the
INTOSC clock when a clock failure is detected.
Depending on the frequency selected by the
IRCF2:IRCF0 bits, this may mean a substantial change
in the speed of code execution. If the WDT is enabled
with a small prescale value, a decrease in clock speed
allows a WDT time-out to occur and a subsequent
device Reset. For this reason, fail-safe clock events
also reset the WDT and postscaler, allowing it to start
timing from when execution speed was changed and
decreasing the likelihood of an erroneous time-out.
FSCM AND THE WATCHDOG TIMER
DS39599G-page 249
Related parts for PIC18F4220-E/P
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![PIC18F-LF1XK50](/images/no-image3.png)
Part Number:
Description:
20-Pin USB Flash Microcontrollers
Manufacturer:
MICROCHIP [Microchip Technology]
Datasheet:
![PIC18F6393T-I/PT](/photos/6/81/68123/c04-066_pf_tmb.jpg)
Part Number:
Description:
PIC18F With 128-segment LCD Driver And 12-bit ADC, 8KB Flash, 768B RAM, CCP, MSS
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F6493T-I/PT](/photos/6/81/68123/c04-066_pf_tmb.jpg)
Part Number:
Description:
PIC18F With 128-segment LCD Driver And 12-bit ADC, 16KB Flash, 768B RAM, CCP, MS
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F8393T-I/PT](/images/manufacturer_photos/0/4/439/microchip_technology_tmb.jpg)
Part Number:
Description:
PIC18F With 192-segment LCD Driver And 12-bit ADC, 8KB Flash, 768B RAM, CCP, MSS
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F8493T-I/PT](/images/manufacturer_photos/0/4/439/microchip_technology_tmb.jpg)
Part Number:
Description:
PIC18F With 192-segment LCD Driver And 12-bit ADC, 16KB Flash, 768B RAM, CCP, MS
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F6585-I/L](/photos/16/12/161282/68-plcc-large-300dpi-lyrd_tmb.jpg)
Part Number:
Description:
Microcontrollers (MCU) 48KB 3328 RAM 52 I/O
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F6680-I/L](/photos/16/12/161282/68-plcc-large-300dpi-lyrd_tmb.jpg)
Part Number:
Description:
Microcontrollers (MCU) 64KB 3328 RAM 52 I/O
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F65K90T-I/MR](/photos/16/3/160368/qfn64_tmb.jpg)
Part Number:
Description:
32kB Flash, 2kB RAM, 1kB EE, NanoWatt XLP, LCD 64 QFN 9x9x0.9mm T/R
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F65K90T-I/PT](/photos/16/3/160367/tqfp-64_tmb.jpg)
Part Number:
Description:
32kB Flash, 2kB RAM, 1kB EE, NanoWatt XLP, LCD 64 TQFP 10x10x1mm T/R
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F87K90T-I/PT](/photos/40/31/403173/tqfp-80_tmb.jpg)
Part Number:
Description:
128kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm T/
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F65K90-I/MR](/photos/16/3/160368/qfn64_tmb.jpg)
Part Number:
Description:
32kB Flash, 2kB RAM, 1kB EE, NanoWatt XLP, LCD 64 QFN 9x9x0.9mm TUBE
Manufacturer:
Microchip Technology
Datasheet:
![PIC18F65K90-I/PT](/photos/16/3/160367/tqfp-64_tmb.jpg)
Part Number:
Description:
32kB Flash, 2kB RAM, 1kB EE, NanoWatt XLP, LCD 64 TQFP 10x10x1mm TRAY
Manufacturer:
Microchip Technology
![PIC18F87K90-I/PT](/photos/40/31/403173/tqfp-80_tmb.jpg)
Part Number:
Description:
128kB Flash, 4kB RAM, 1kB EE, 16MIPS, NanoWatt XLP, LCD, 5V 80 TQFP 12x12x1mm TR
Manufacturer:
Microchip Technology