PIC16F74-I/P Microchip Technology, PIC16F74-I/P Datasheet - Page 119

• Manufacturer Part Number: PIC16F74-I/P
• Description: IC MCU FLASH 4KX14 A/D 40DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F74-I/P

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Number Of I /o: 33
• 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: 40-DIP (0.600", 15.24mm)
• Controller Family/series: PIC16F
• No. Of I/o's: 33
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Package: 40PDIP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 33
• Interface Type: I2C/SPI/USART
• On-chip Adc: 8-chx8-bit
• Number Of Timers: 3
• Processor Series: PIC16F
• Core: PIC
• Data Ram Size: 192 B
• Maximum Clock Frequency: 20 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: ICE2000, DM163022
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: 444-1001 - DEMO BOARD FOR PICMICRO MCU
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

7.8
7.9
7.10
1997 Microchip Technology Inc.
Protection Against Spurious Writes
Data EEPROM Operation During Code Protected Configuration
Initialization
There are conditions when the device may not want to write to the data EEPROM memory. To
protect against spurious EEPROM writes, various mechanisms have been built-in. On power-up,
WREN is cleared. Also, the Power-up Timer (72 ms duration) prevents EEPROM write.
The write initiate sequence and the WREN bit together help prevent an accidental write during
brown-outs, power glitches, and software malfunction.
When the device is code protected, the CPU is able to read and write data to the Data EEPROM.
For ROM devices, there are two code protection bits. One for the ROM program memory and one
for the Data EEPROM memory. See the Device Programming Specification for more information
about these bits.
The Data EEPROM module does not have an initialization sequence such as other modules. To
do a read of the Data EEPROM refer to
to
As for the General Purpose RAM, it is a good idea to initialize all Data EEPROM locations to a
known state. This initialization may take place at the time of device programming or an applica-
tion diagnostic mode, since on reset you may not want the Data EEPROM to be cleared.
An Application Diagnostic mode may be a condition on the I/O pins that the device tests for after
the device power-ups. Then depending on this mode, the device would do some diagnostic func-
tion. The state for the I/O pins would need to be something that would not be possible without the
injected levels to force this diagnostic mode.
Example
7-2, and to verify that the write completed successfully refer to
Section 7. Data EEPROM
Example
7-1. To do a write to the Data EEPROM refer
Example
DS31007A-page 7-7
7-3.
7