PCM18XK1 Microchip Technology, PCM18XK1 Datasheet - Page 229

• Manufacturer Part Number: PCM18XK1
• Description: MODULE PROC PIC18F8680,6680,8565
• Manufacturer: Microchip Technology

Specifications of PCM18XK1

• Accessory Type: Processor Module
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• For Use With/related Products: ICE2000
• For Use With: ICE2000 - EMULATOR MPLAB-ICE 2000 POD
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

17.4.17.3
Bus collision occurs during a Stop condition if:
a)
b)
FIGURE 17-31:
FIGURE 17-32:
 2004 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.
SSPIF
BCLIF
SDA
SCL
PEN
BCLIF
P
SSPIF
SDA
PEN
SCL
P
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
T
BRG
BRG
PIC18F6585/8585/6680/8680
T
T
BRG
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’ (Figure 17-31). 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 17-32).
SCL goes low before SDA goes high,
set BCLIF
T
T
BRG
BRG
SDA sampled
low after T
set BCLIF
DS30491C-page 227
‘0’
‘0’
‘0’
‘0’
BRG
,