PIC16F873A-I/SS Microchip Technology, PIC16F873A-I/SS Datasheet - Page 119

• Manufacturer Part Number: PIC16F873A-I/SS
• Description: IC MCU FLASH 4KX14 EE 28SSOP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F873A-I/SS

• Core Size: 8-Bit
• Program Memory Size: 7KB (4K x 14)
• Core Processor: PIC
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SSOP
• Controller Family/series: PIC16F
• No. Of I/o's: 22
• Eeprom Memory Size: 128Byte
• Ram Memory Size: 192Byte
• Cpu Speed: 20MHz
• No. Of Timers: 3
• Core: PIC
• Processor Series: PIC16F
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Data Ram Size: 192 B
• Data Rom Size: 128 B
• On-chip Adc: Yes
• Number Of Programmable I/os: 22
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit
• A/d Channels Available: 5
• Height: 1.75 mm
• Interface Type: I2C, SPI, USART
• Length: 10.2 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Width: 5.3 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164307 - MODULE SKT FOR PM3 28SSOPAC164020 - MODULE SKT PROMATEII 44TQFPXLT28SS-1 - SOCKET TRANSITION ICE 28SSOP
• Lead Free Status / Rohs Status: Details
• Other names: PIC16F873AI/SS

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