PIC16F913-I/SP Microchip Technology Inc., PIC16F913-I/SP Datasheet - Page 80

• Manufacturer Part Number: PIC16F913-I/SP
• Description: 28 PIN, 7 KB FLASH, 352 RAM, 25 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F913-I/SP

• A/d Inputs: 5-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 25
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 28-pin SPDIP
• Programmable Memory: 7K Bytes
• Ram Size: 256 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

PIC16F917/916/914/913
4.5.2
The Oscillator Start-up Time-out Status (OSTS) bit
(OSCCON<3>) indicates whether the system clock is
running from the external clock source, as defined by
the FOSC bits, or from the internal clock source. In
particular, OSTS indicates that the Oscillator Start-up
Timer (OST) has timed out for LP, XT or HS modes.
4.6
Two-Speed Start-up mode provides additional power
savings by minimizing the latency between external
oscillator start-up and code execution. In applications
that make heavy use of the Sleep mode, Two-Speed
Start-up will remove the external oscillator start-up
time from the time spent awake and can reduce the
overall power consumption of the device.
This mode allows the application to wake-up from
Sleep, perform a few instructions using the INTOSC
as the clock source and go back to Sleep without
waiting for the primary oscillator to become stable.
When the PIC16F917/916/914/913 is configured for
LP, XT or HS modes, the Oscillator Start-up Timer
(OST) is enabled (see Section 4.3.1 “Oscillator
Start-up Timer (OST)”). The OST timer will suspend
program execution until 1024 oscillations are counted.
Two-Speed Start-up mode minimizes the delay in code
execution by operating from the internal oscillator as
the OST is counting. When the OST count reaches
1024 and the OSTS bit (OSCCON<3>) is set, program
execution switches to the external oscillator.
4.6.1
Two-Speed Start-up mode is configured by the
following settings:
• IESO = 1 (CONFIG<10>) Internal/External
• SCS = 0.
• FOSC configured for LP, XT or HS mode.
Two-Speed Start-up mode is entered after:
• Power-on Reset (POR) and, if enabled, after
• Wake-up from Sleep.
If the external clock oscillator is configured to be anything
other than LP, XT or HS mode, then Two-Speed Start-up
is disabled. This is because the external clock oscillator
does not require any stabilization time after POR or an
exit from Sleep.
DS41250E-page 78
Note:
Switchover bit.
PWRT has expired, or
Two-Speed Clock Start-up Mode
OSCILLATOR START-UP TIME-OUT
STATUS BIT
Executing a SLEEP instruction will abort
the oscillator start-up time and will cause
the OSTS bit (OSCCON<3>) to remain
clear.
TWO-SPEED START-UP MODE
CONFIGURATION
Preliminary
4.6.2
1.
2.
3.
4.
5.
6.
7.
4.6.3
Checking the state of the OSTS bit (OSCCON<3>) will
confirm if the PIC16F917/916/914/913 is running from
the external clock source as defined by the FOSC bits
in the Configuration Word (CONFIG) or the internal
oscillator.
Wake-up from Power-on Reset or Sleep.
Instructions begin execution by the internal
oscillator at the frequency set in the IRCF bits
(OSCCON<6:4>).
OST enabled to count 1024 clock cycles.
OST timed out, wait for falling edge of the
internal oscillator.
OSTS is set.
System clock held low until the next falling edge
of new clock (LP, XT or HS mode).
System clock is switched to external clock
source.
TWO-SPEED START-UP
SEQUENCE
CHECKING EXTERNAL/INTERNAL
CLOCK STATUS
© 2005 Microchip Technology Inc.