PIC16F688T-I/SL Microchip Technology, PIC16F688T-I/SL Datasheet - Page 192

• Manufacturer Part Number: PIC16F688T-I/SL
• Description: IC MCU PIC FLASH 4KX14 14SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F688T-I/SL

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, WDT
• Number Of I /o: 12
• Program Memory Type: FLASH
• 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
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Controller Family/series: PIC16F
• No. Of I/o's: 12
• Eeprom Memory Size: 256Byte
• Ram Memory Size: 256Byte
• Cpu Speed: 20MHz
• No. Of Timers: 2
• 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, Lead free / RoHS Compliant
• Other names: PIC16F688T-I/SL; PIC16F688T-I/SLTR

PICmicro MID-RANGE MCU FAMILY
12.12
DS31012A-page 12-12
Design Tips
Question 1:
Answer 1:
There are a few reasons that this could occur
1.
2.
You should never write to Timer1, where that could cause the loss of time. In most cases
that means you should not write to the TMR1L register, but if the conditions are ok, you
may write to the TMR1H register. Normally you write to the TMR1H register if you want the
Timer1 overflow interrupt to be sooner then the full 16-bit time-out.
You should ensure the your layout uses good PCB layout techniques so that noise does
not couple onto the Timer1 oscillator lines.
Timer1 does not seem to be keeping accurate time.
1997 Microchip Technology Inc.