PIC18F24J11 MICROCHIP [Microchip Technology], PIC18F24J11 Datasheet - Page 314

• Manufacturer Part Number: PIC18F24J11
• Description: 28/44-Pin, Low-Power, High-Performance USB Microcontrollers with nanoWatt XLP Technology
• Manufacturer: MICROCHIP [Microchip Technology]

suspended, leaving the SDAx line held low and the Start
PIC18F46J11 FAMILY
19.5.7.2
Clock arbitration occurs when the master, during any
receive, transmit or Repeated Start/Stop condition,
deasserts the SCLx pin (SCLx allowed to float high).
When the SCLx pin is allowed to float high, the BRG is
suspended from counting until the SCLx pin is actually
FIGURE 19-20:
19.5.8
To initiate a Start condition, the user sets the Start
Enable bit, SEN (SSPxCON2<0>). If the SDAx and
SCLx pins are sampled high, the BRG is reloaded with
the contents of SSPxADD<6:0> and starts its count. If
SCLx and SDAx are both sampled high when the Baud
Rate Generator times out (T
driven low. The action of the SDAx being driven low
while SCLx is high is the Start condition and causes the
Start bit (SSPxSTAT<3>) to be set. Following this, the
BRG is reloaded with the contents of SSPxADD<6:0>
and resumes its count. When the BRG times out
(T
automatically cleared by hardware. The BRG is
condition is complete.
FIGURE 19-21:
DS39932D-page 314
BRG
), the SEN bit (SSPxCON2<0>) will be
I
CONDITION TIMING
2
Clock Arbitration
C MASTER MODE START
SDAx
SCLx
BRG
Value
BRG
Reload
Write to SEN bit occurs here
BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION
FIRST START BIT TIMING
SDAx
SCLx
03h
BRG
DX
), the SDAx pin is
SCLx deasserted but slave holds
SCLx low (clock arbitration)
02h
SCLx is sampled high, reload takes
place and BRG starts its count
SDAx = 1,
SCLx = 1
T
BRG
01h
Set S bit (SSPxSTAT<3>)
T
S
BRG
BRG decrements on
Q2 and Q4 cycles
00h (hold off)
At completion of Start bit,
hardware clears SEN bit
sampled high. When the SCLx pin is sampled high, the
BRG is reloaded with the contents of SSPxADD<6:0>
and begins counting. This ensures that the SCLx high
time will always be at least one BRG rollover count in
the event that the clock is held low by an external
device
19.5.8.1
If the user writes the SSPxBUF when a Start sequence
is in progress, the WCOL bit is set and the contents of
the buffer are unchanged (the write does not occur).
and sets SSPxIF bit
Note:
Note:
DX – 1
Write to SSPxBUF occurs here
T
BRG
(Figure
1st bit
If, at the beginning of the Start condition,
the SDAx and SCLx pins are already sam-
pled low or if during the Start condition, the
SCLx line is sampled low, before the SDAx
line is driven low, a bus collision occurs, the
Bus Collision Interrupt Flag, BCLxIF, is set,
the Start condition is aborted and the I
module is reset into its Idle state.
Because queueing of events is not
allowed, writing to the lower five bits of
SSPxCON2 is disabled until the Start
condition is complete.
WCOL Status Flag
SCLx allowed to transition high
T
19-20).
BRG
03h
 2011 Microchip Technology Inc.
02h
2nd bit
2
C