PIC16F1938-I/ML Microchip Technology, PIC16F1938-I/ML Datasheet - Page 119

• Manufacturer Part Number: PIC16F1938-I/ML
• Description: IC MCU 8BIT FLASH 28QFN
• Manufacturer: Microchip Technology
• Series: PIC® XLP™ 16Fr

Specifications of PIC16F1938-I/ML

• Core Size: 8-Bit
• Program Memory Size: 28KB (16K x 14)
• Oscillator Type: Internal
• Core Processor: PIC
• Speed: 32MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-VQFN Exposed Pad, 28-HVQFN, 28-SQFN, 28-DHVQFN
• Controller Family/series: PIC16F
• No. Of I/o's: 25
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 1024Byte
• Cpu Speed: 32MHz
• Package: 28QFN EP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 32 MHz
• Operating Supply Voltage: 2.5|3.3|5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 25
• Interface Type: I2C/SPI/USART
• On-chip Adc: 11-chx10-bit
• Number Of Timers: 5
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.6
The system clock source can be switched between
external and internal clock sources via software using
the System Clock Select (SCS) bits of the OSCCON
register.
8.6.1
The System Clock Select (SCS) bits of the OSCCON
register selects the system clock source that is used for
the CPU and peripherals.
• When the SCS bits of the OSCCON register = 00,
• When the SCS bits of the OSCCON register = 01,
• When the SCS bits of the OSCCON register = 1x,
8.6.2
The Oscillator Start-up Time-out Status (OSTS) bit of
the OSCSTAT register indicates whether the system
clock is running from the external clock source, as
defined by the FOSC<2:0> bits in the Configuration
Word Register 1 (CONFIG1), 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.
8.6.3
The Timer1 Oscillator Ready (T1OSCR) bit of the
OSCSTAT register indicates whether the Timer1
oscillator is ready to be used. After the T1OSCR bit is
set, the SCS bits can be configured to select the Timer1
oscillator.
© 2009 Microchip Technology Inc.
the system clock source is determined by
configuration of the FOSC<2:0> bits in the
Configuration Word Register 1 (CONFIG1).
the system clock source is the Timer1 oscillator.
the system clock source is chosen by the internal
oscillator frequency selected by the IRCF<3:0>
bits of the OSCCON register. After a Reset, the
SCS bit of the OSCCON register is always
cleared.
Note:
Clock Switching
SYSTEM CLOCK SELECT (SCS) BIT
Any automatic clock switch, which may
occur from Two-Speed Start-up or Fail-Safe
Clock Monitor, does not update the SCS
bits of the OSCCON register. The user can
monitor the OSTS bit of the OSCSTAT
register to determine the current system
clock source.
OSCILLATOR START-UP TIME-OUT
STATUS (OSTS) BIT
TIMER1
(T1OSCR) BIT
OSCILLATOR READY
Preliminary
8.7
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 external oscillator to become stable.
When the oscillator module is configured for LP, XT or
HS modes, the Oscillator Start-up Timer (OST) is
enabled (see Section 8.4.1 “Oscillator Start-up
Timer (OST)”). The OST will suspend program execu-
tion 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 of the OSCSTAT register is set, program exe-
cution switches to the external oscillator.
8.7.1
Two-Speed Start-up mode is configured by the
following settings:
• IESO (of the Configuration Word Register 1) = 1;
• SCS (of the OSCCON register) = 00.
• FOSC<2:0> bits in the Configuration Word
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.
PIC16F193X/LF193X
Note:
Internal/External Switchover bit (Two-Speed
Start-up mode enabled).
Register 1 (CONFIG1) configured for LP, XT or
HS mode.
Power-up Timer (PWRT) has expired, or
Two-Speed Clock Start-up Mode
Executing a SLEEP instruction will abort
the oscillator start-up time and will cause
the OSTS bit of the OSCSTAT register to
remain clear.
TWO-SPEED START-UP MODE
CONFIGURATION
DS41364C-page 119