PIC16F688-I/SL Microchip Technology, PIC16F688-I/SL Datasheet - Page 46

• Manufacturer Part Number: PIC16F688-I/SL
• Description: IC PIC MCU FLASH 4KX14 14SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688-I/SL

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: SCI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 12
• Number Of Timers: 1
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT14SO-1 - SOCKET TRANSITION 14SOIC 150/208AC162061 - HEADER INTRFC MPLAB ICD2 20PINAC162056 - HEADER INTERFACE ICD2 16F688
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
2.5.1
DS31002A-page 2-16
Clock Out
A calibration instruction is programmed into the last address of the implemented program
memory. This instruction contains the calibration value for the internal RC oscillator. This value
is programmed as a RETLW XX instruction where XX is the calibration value. In order to retrieve
the calibration value, issue a CALL YY instruction where YY is the last location in the device’s user
accessible program memory. The calibration value is now loaded in the W register. The program
should then perform a MOVWF OSCCAL instruction to load the value into the internal RC oscillator
calibration register.
of the program memory.
Table 2-5:
The internal RC oscillator can be configured to provide a clock out signal on the CLKOUT pin
when the configuration word address (2007h) is programmed with FOSC2, FOSC1, FOSC0
equal to ‘101’ for Internal RC or ‘111’ for External RC. CLKOUT, which is divided by 4, can be
used for test purposes or to synchronize other logic.
When the calibration value of the internal RC oscillator is accidently erased, the clock out feature
allows the user to determine what the calibration value should be. This is achieved by writing a
program which modifies (increments/decrements) the value of the OSCCAL register. When the
CLKOUT pin is at 4 MHz ( 1.5%) at 5V and 25˚C, the OSCCAL register has the correct calibra-
tion value. This value then needs to be written to a port or shifted out serially, so that the value
can be written down and programmed into the calibration location.
Memory Size
Note 1: Erasing the device (windowed devices) will also erase the factory programmed
Note 2: OSCCAL<1:0> are unimplemented and should be written as ‘0’. This will help
Program
(Words)
512
1K
2K
4K
8K
calibration value for the internal oscillator.
Prior to erasing a windowed device, the internal oscillator calibration value must be
saved. It is a good idea to write this value on the package of the device to ensure
that the calibration value is not accidently lost.
This saved valued must be restored into program memory calibration location before
programming the device.
ensure compatibility with future devices.
Calibration Value Location
Calibration Value
Table 2-5
Location
1FFFh
FFFh
1FFh
3FFh
7FFh
shows the location of the calibration value depending on the size
1997 Microchip Technology Inc.