PIC16LC923-04I/L Microchip Technology, PIC16LC923-04I/L Datasheet - Page 72

• Manufacturer Part Number: PIC16LC923-04I/L
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,LDCC,68PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Cr

Specifications of PIC16LC923-04I/L

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: I²C, SPI
• Peripherals: LCD, POR, PWM, WDT
• Number Of I /o: 25
• Program Memory Size: 7KB (4K x 14)
• Program Memory Type: OTP
• Ram Size: 176 x 8
• Voltage - Supply (vcc/vdd): 2.5 V ~ 6 V
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 68-PLCC
• Processor Series: PIC16LC
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 176 B
• Interface Type: I2C, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 25
• Number Of Timers: 3
• Operating Supply Voltage: 2.5 V to 6 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
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details

PIC16C9XX
11.2.4
The I
one master. This is called multi-master. When two or
more masters try to transfer data at the same time, arbi-
tration and synchronization occur.
11.2.4.1
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
(Figure 11-16), and turns off its data 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, arbitration continues into the data.
FIGURE 11-16: MULTI-MASTER
Masters that also incorporate the slave function, and
have lost arbitration must immediately switch over to
slave-receiver mode. This is because the winning mas-
ter-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 condi-
Care needs to be taken to ensure that these conditions
do not occur.
DS30444E - page 72
tion
DATA 2
SDA
SCL
DATA 1
2
C protocol allows a system to have more than
MULTI-MASTER
ARBITRATION
ARBITRATION
(TWO MASTERS)
transmitter 1 loses arbitration
DATA 1 SDA
11.2.4.2 Clock Synchronization
Clock synchronization occurs after the devices have
started arbitration. This is performed using a
wired-AND connection to the SCL line. A high to low
transition on the SCL line causes the concerned
devices to start counting off their low period. Once a
device clock has gone low, it will hold the SCL line low
until its SCL high state is reached. The low to high tran-
sition of this clock may not change the state of the SCL
line, if another device clock is still within its low period.
The SCL line is held low by the device with the longest
low period. Devices with shorter low periods enter a
high wait-state, until the SCL line comes high. When the
SCL line comes high, all devices start counting off their
high periods. The first device to complete its high period
will pull the SCL line low. The SCL line high time is
determined by the device with the shortest high period,
Figure 11-17.
FIGURE 11-17: CLOCK SYNCHRONIZATION
SCL
CLK
CLK
1
2
counter
reset
state
1997 Microchip Technology Inc.
wait
start counting
HIGH period