PIC16F877A-I/PT Microchip Technology Inc., PIC16F877A-I/PT Datasheet - Page 94
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PIC16F877A-I/PT
Manufacturer Part Number
PIC16F877A-I/PT
Description
44 PIN, 7 KB FLASH, 368 RAM, 33 I/O
Manufacturer
Microchip Technology Inc.
Datasheet
1.PIC16F877A-IPT.pdf
(218 pages)
Specifications of PIC16F877A-I/PT
A/d Inputs
8-Channel, 10-Bit
Comparators
2
Cpu Speed
5 MIPS
Eeprom Memory
256 Bytes
Input Output
33
Interface
I2C/SPI/USART
Memory Type
Flash
Number Of Bits
8
Package Type
44-pin TQFP
Programmable Memory
14K Bytes
Ram Size
368 Bytes
Speed
20 MHz
Timers
2-8-bit, 1-16-bit
Voltage, Range
2-5.5 V
Lead Free Status / Rohs Status
RoHS Compliant part
Electrostatic Device
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
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Part Number:
PIC16F877A-I/PT
Manufacturer:
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Quantity:
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Manufacturer:
Microchip Technology
Quantity:
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PIC16F87X
9.2.18.2
During a Repeated START condition, a bus collision
occurs if:
a)
b)
When the user de-asserts SDA and the pin is allowed
to float high, the BRG is loaded with SSPADD<6:0>
and counts down to 0. The SCL pin is then de-asserted,
and when sampled high, the SDA pin is sampled. If
SDA is low, a bus collision has occurred (i.e., another
master is attempting to transmit a data’0’). If, however,
FIGURE 9-23:
FIGURE 9-24:
DS30292C-page 92
A low level is sampled on SDA when SCL goes
from low level to high level.
SCL goes low before SDA is asserted low, indi-
cating that another master is attempting to trans-
mit a data ’1’.
SDA
SCL
BCLIF
RSEN
S
SSPIF
SDA
SCL
RSEN
BCLIF
S
SSPIF
Bus Collision During a Repeated
START Condition
’0’
’0’
’0’
’0’
BUS COLLISION DURING A REPEATED START CONDITION (CASE 1)
BUS COLLISION DURING REPEATED START CONDITION (CASE 2)
SCL goes low before SDA,
Set BCLIF. Release SDA and SCL.
T
BRG
Sample SDA when SCL goes high.
If SDA = 0, set BCLIF and release SDA and SCL.
SDA is sampled high, the BRG is reloaded and begins
counting. If SDA goes from high to low before the BRG
times out, no bus collision occurs, because no two
masters can assert SDA at exactly the same time.
If, however, SCL goes from high to low before the BRG
times out and SDA has not already been asserted, a
bus collision occurs. In this case, another master is
attempting to transmit a data’1’ during the Repeated
START condition.
If at the end of the BRG time-out, both SCL and SDA
are still high, the SDA pin is driven low, the BRG is
reloaded and begins counting. At the end of the count,
regardless of the status of the SCL pin, the SCL pin is
driven low and the Repeated START condition is
complete (Figure 9-23).
T
Cleared in software
BRG
2001 Microchip Technology Inc.
Interrupt cleared
in software
’0’
’0’
’0’
’0’