PIC18F1320-H/P Microchip Technology, PIC18F1320-H/P Datasheet - Page 186

• Manufacturer Part Number: PIC18F1320-H/P
• Description: IC MCU 8BIT 8KB FLASH 18PDIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F1320-H/P

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 25MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, LVD, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 7x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 150°C
• Package / Case: 18-DIP (0.300", 7.62mm)
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC18F1220/1320
19.4.4
The FSCM is designed to detect oscillator failure at any
point after the device has exited Power-on Reset
(POR) or Low-Power Sleep mode. When the primary
system clock is EC, RC or INTRC modes, monitoring
can begin immediately following these events.
For oscillator modes involving a crystal or resonator
(HS, HSPLL, LP or XT), the situation is somewhat dif-
ferent. Since the oscillator may require a start-up time
considerably longer than the FCSM sample clock time,
a false clock failure may be detected. To prevent this,
the internal oscillator block is automatically configured
as the system clock and functions until the primary
clock is stable (the OST and PLL timers have timed
out). This is identical to Two-Speed Start-up mode.
Once the primary clock is stable, the INTRC returns to
its role as the FSCM source
DS39605F-page 184
POR OR WAKE FROM SLEEP
As noted in Section 19.3.1 “Special Considerations
for Using Two-Speed Start-up”, it is also possible to
select another clock configuration and enter an alter-
nate power managed mode while waiting for the
primary system clock to become stable. When the new
powered managed mode is selected, the primary clock
is disabled.
Note:
The same logic that prevents false oscilla-
tor failure interrupts on POR or wake from
Sleep will also prevent the detection of the
oscillator’s failure to start at all following
these events. This can be avoided by
monitoring the OSTS bit and using a
timing routine to determine if the oscillator
is taking too long to start. Even so, no
oscillator failure interrupt will be flagged.
© 2007 Microchip Technology Inc.