PIC17C756A MICROCHIP [Microchip Technology], PIC17C756A Datasheet - Page 174

• Manufacturer Part Number: PIC17C756A
• Description: High-Performance 8-bit CMOS EPROM Microcontrollers with 10-bit A/D
• Manufacturer: MICROCHIP [Microchip Technology]

PIC17C7XX
15.2.18.3
Bus collision occurs during a STOP condition if:
a)
b)
FIGURE 15-40:
FIGURE 15-41:
DS30289B-page 174
After the SDA pin has been de-asserted and
allowed to float high, SDA is sampled low after
the BRG has timed out.
After the SCL pin is de-asserted, SCL is sam-
pled low before SDA goes high.
SDA
SCL
PEN
BCLIF
P
SSPIF
SSPIF
BCLIF
SDA
PEN
SCL
Bus Collision During a STOP
Condition
P
’0’
’0’
’0’
’0’
BUS COLLISION DURING A STOP CONDITION (CASE 1)
BUS COLLISION DURING A STOP CONDITION (CASE 2)
Assert SDA.
T
SDA asserted low.
BRG
T
BRG
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 SSPADD<6:0>
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'. 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 15-40).
SCL goes low before SDA goes high.
Set BCLIF.
T
BRG
T
BRG
2000 Microchip Technology Inc.
’0’
’0’
SDA sampled
low after T
Set BCLIF.
BRG
,