PIC16F874A-I/L Microchip Technology, PIC16F874A-I/L Datasheet - Page 660

• Manufacturer Part Number: PIC16F874A-I/L
• Description: IC MCU FLASH 4KX14 EE 44PLCC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F874A-I/L

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 44-PLCC
• 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
• Eeprom Size: 128 x 8
• Ram Size: 192 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• 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
• 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, DM163022, DV164120
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8-ch x 10-bit
• Data Rom Size: 128 B
• Height: 3.87 mm
• Length: 16.59 mm
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 4 V
• Width: 16.59 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AC164309 - MODULE SKT FOR PM3 44PLCC444-1001 - DEMO BOARD FOR PICMICRO MCUDVA16XL441 - ADAPTER DEVICE ICE 44PLCC309-1040 - ADAPTER 44-PLCC ZIF TO 40-DIP309-1039 - ADAPTER 44-PLCC TO 40-DIPDV007003 - PROGRAMMER UNIVERSAL PROMATE II
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: PIC16F874AI/L

PICmicro MID-RANGE MCU FAMILY
A.4
A.4.1
DS31034A-page 34-8
Multi-master
Arbitration
The I
When two or more masters try to transfer data at the same time, arbitration and synchronization
occur.
Arbitration takes place on the SDA line, while the SCL line is high. The master which transmits a
high when the other master transmits a low loses arbitration
output stage. A master which lost arbitration can generate clock pulses until the end of the data
byte where it lost arbitration. When the master devices are addressing the same device, arbitra-
tion continues into the data.
Figure A-9:
Masters that also incorporate the slave function, and have lost arbitration must immediately
switch over to slave-receiver mode. This is because the winning master-transmitter may be
addressing it.
Arbitration is not allowed between:
• A repeated START condition
• A STOP condition and a data bit
• A repeated START condition and a STOP condition
Care needs to be taken to ensure that these conditions do not occur.
2
C protocol allows a system to have more than one master. This is called multi-master.
Multi-Master Arbitration (Two Masters)
DATA 2
SDA
SCL
DATA 1
transmitter 1 loses arbitration
DATA 1 SDA
(Figure
1997 Microchip Technology Inc.
A-9), and turns off its data