PIC16F74-I/ML Microchip Technology, PIC16F74-I/ML Datasheet - Page 494

• Manufacturer Part Number: PIC16F74-I/ML
• Description: IC MCU FLASH 4KX14 A/D 44QFN
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F74-I/ML

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 33
• Program Memory Size: 7KB (4K x 14)
• Program Memory Type: FLASH
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-QFN
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 192 B
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 33
• Number Of Timers: 3 bit
• 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: ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8
• For Use With: XLT44QFN2 - SOCKET TRAN ICE 44QFN/40DIPAC164322 - MODULE SOCKET MPLAB PM3 28/44QFN444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

PICmicro MID-RANGE MCU FAMILY
26.6
DS31026A-page 26-10
Design Tips
Question 1:
Answer 1:
The WDT was not designed to be a recovery from a brown-out condition. It was designed to
recover from errant software operation (the device remaining in the specified operating ranges).
If your system can be subjected to brown-outs, either the on-chip brown-out circuitry should be
enabled or an external brown-out circuit should be implemented.
Question 2:
Answer 2:
Make sure that the loop with the CLRWDT instruction meets the minimum specification of the WDT
(not the typical).
Question 3:
Answer 3:
On power-up, you must take into account the Oscillator Start-up time (Tost). Sometimes it helps
to put the CLRWDT instruction at the beginning of the loop, since this start-up time may be variable.
My system voltage drops and then returns to the specified device voltage
range. The device is not operating correctly and the WDT does not reset and
return the device to proper operation.
Device resets even though I do the CLRWDT instruction in my loop.
Device never gets out of resets.
1997 Microchip Technology Inc.