PIC18F2550-I/SP Microchip Technology, PIC18F2550-I/SP Datasheet - Page 234

• Manufacturer Part Number: PIC18F2550-I/SP
• Description: IC PIC MCU FLASH 16KX16 28DIP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F2550-I/SP

• Program Memory Type: FLASH
• Program Memory Size: 32KB (16K x 16)
• Package / Case: 28-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, HLVD, POR, PWM, WDT
• Number Of I /o: 24
• Eeprom Size: 256 x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 10x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC18F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 1536 B
• Interface Type: SPI, I2C, EAUSART
• Maximum Clock Frequency: 48 MHz
• Number Of Programmable I/os: 24
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734, 52712-325, EWPIC18
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, ICE4000, DM163025, DV164136
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 10 Channel
• Package: 28SPDIP
• Device Core: PIC
• Family Name: PIC18
• Maximum Speed: 48 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3-DB18F4550 - BOARD DAUGHTER ICEPIC3DM163025 - PIC DEM FULL SPEED USB DEMO BRDDVA18XP280 - DEVICE ADAPTER 18F2220 PDIP 28LD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PIC18F2455/2550/4455/4550
19.4.17.1
During a Start condition, a bus collision occurs if:
a)
b)
During a Start condition, both the SDA and the SCL
pins are monitored.
If the SDA pin is already low, or the SCL pin is already
low, then all of the following occur:
• the Start condition is aborted,
• the BCLIF flag is set and
• the MSSP module is reset to its inactive state
The Start condition begins with the SDA and SCL pins
deasserted. When the SDA pin is sampled high, the
Baud Rate Generator is loaded from SSPADD<6:0>
and counts down to ‘0’. If the SCL pin is sampled low
while SDA is high, a bus collision occurs because it is
assumed that another master is attempting to drive a
data ‘1’ during the Start condition.
FIGURE 19-28:
DS39632D-page 232
(Figure 19-28).
SDA or SCL are sampled low at the beginning of
the Start condition (Figure 19-28).
SCL is sampled low before SDA is asserted low
(Figure 19-29).
SDA
SCL
SEN
BCLIF
S
SSPIF
Bus Collision During a Start
Condition
BUS COLLISION DURING START CONDITION (SDA ONLY)
condition if SDA = 1, SCL = 1
Set SEN, enable Start
SDA sampled low before
Start condition. Set BCLIF.
S bit and SSPIF set because
SDA = 0, SCL = 1.
SDA goes low before the SEN bit is set.
Set BCLIF,
S bit and SSPIF set because
SDA = 0, SCL = 1.
Preliminary
SSPIF and BCLIF are
cleared in software
If the SDA pin is sampled low during this count, the
BRG is reset and the SDA line is asserted early
(Figure 19-30). If, however, a ‘1’ is sampled on the SDA
pin, the SDA pin is asserted low at the end of the BRG
count. The Baud Rate Generator is then reloaded and
counts down to ‘0’. If the SCL pin is sampled as ‘0’,
during this time a bus collision does not occur. At the
end of the BRG count, the SCL pin is asserted low.
Note:
SEN cleared automatically because of bus collision.
MSSP module reset into Idle state.
The reason that bus collision is not a factor
during a Start condition is that no two bus
masters can assert a Start condition at the
exact same time. Therefore, one master
will always assert SDA before the other.
This condition does not cause a bus
collision because the two masters must be
allowed to arbitrate the first address
following the Start condition. If the address
is the same, arbitration must be allowed to
continue into the data portion, Repeated
Start or Stop conditions.
SSPIF and BCLIF are
cleared in software
© 2007 Microchip Technology Inc.