PIC12F1822 MICROCHIP [Microchip Technology], PIC12F1822 Datasheet - Page 271

• Manufacturer Part Number: PIC12F1822
• Description: 8/14-Pin Flash Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

24.6.13.3
Bus collision occurs during a Stop condition if:
a)
b)
FIGURE 24-38:
FIGURE 24-39:
 2010 Microchip Technology Inc.
After the SDA pin has been deasserted and
allowed to float high, SDA is sampled low after
the BRG has timed out.
After the SCL pin is deasserted, SCL is sampled
low before SDA goes high.
SDA
SCL
PEN
BCL1IF
P
SSP1IF
SDA
SCL
PEN
BCL1IF
P
SSP1IF
Bus Collision During a Stop
Condition
BUS COLLISION DURING A STOP CONDITION (CASE 1)
BUS COLLISION DURING A STOP CONDITION (CASE 2)
SDA asserted low
Assert SDA
T
BRG
T
BRG
PIC12F/LF1822/16F/LF1823
Preliminary
T
BRG
T
BRG
The Stop condition begins with SDA asserted low.
When SDA is sampled low, the SCL pin is allowed to
float. When the pin is sampled high (clock arbitration),
the Baud Rate Generator is loaded with SSP1ADD and
counts down to 0. After the BRG times out, SDA is
sampled. If SDA is sampled low, a bus collision has
occurred. This is due to another master attempting to
drive a data ‘0’ (Figure 24-37). If the SCL pin is sampled
low before SDA is allowed to float high, a bus collision
occurs. This is another case of another master
attempting to drive a data ‘0’ (Figure 24-38).
SCL goes low before SDA goes high,
set BCL1IF
T
BRG
T
BRG
SDA sampled
low after T
set BCL1IF
’0’
’0’
DS41413A-page 271
’0’
’0’
BRG
,