PIC18F-LF1XK50 Datasheet, PDF (167/420 Pages) Microchip Technology – 20-Pin USB Flash Microcontrollers

15.3.7 BAUD RATE
In I²C Master mode, the Baud Rate Generator (BRG)
reload value is placed in the SSPADD register
(Figure 15-17). When a write occurs to SSPBUF, the
Baud Rate Generator will automatically begin counting.
Once the given operation is complete (i.e.,
transmission of the last data bit is followed by ACK), the
internal clock will automatically stop counting and the
SCL pin will remain in its last state.
PIC18F/LF1XK50
Table 15-3 demonstrates clock rates based on
instruction cycles and the BRG value loaded into
SSPADD.
EQUATION 15-1:
FSCL = _---S---S----P----A----FD---^O-D---^S--^C-+------1---_---_--4---_-
FIGURE 15-17:
BAUD RATE GENERATOR BLOCK DIAGRAM
SSPM<3:0>
SSPADD<7:0>
SSPM<3:0>
SCL
Reload
Control
Reload
CLKOUT
BRG Down Counter
FOSC/2
TABLE 15-3: I²C™ CLOCK RATE W/BRG
FOSC
FCY
BRG Value
FSCL
(2 Rollovers of BRG)
48 MHz
12 MHz
0Bh
1 MHz⁽¹⁾
48 MHz
12 MHz
1Dh
400 kHz
48 MHz
40 MHz
12 MHz
10 MHz
77h
100 kHz
18h
400 kHz⁽¹⁾
40 MHz
10 MHz
1Fh
312.5 kHz
40 MHz
16 MHz
10 MHz
4 MHz
63h
100 kHz
09h
400 kHz⁽¹⁾
16 MHz
4 MHz
0Ch
308 kHz
16 MHz
4 MHz
4 MHz
1 MHz
27h
100 kHz
02h
333 kHz⁽¹⁾
Note 1:
4 MHz
1 MHz
09h
100 kHz
4 MHz
1 MHz
00h
1 MHz⁽¹⁾
The I²C interface does not conform to the 400 kHz I²C specification (which applies to rates greater than
100 kHz) in all details, but may be used with care where higher rates are required by the application.
 2010 Microchip Technology Inc.
Preliminary
DS41350E-page 167