BAT32G1x9 user manual | Chapter 19 Universal serial communication unit
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Rev.1.02
19.6.4
Calculate the transmit clock frequency
The transmit clock frequency of the slave select input function (SSPI00) communication can be calculated using
the following calculation equation.
(1) Slaves
Note The maximum allowable transmit clock frequency is f
MCK
/6.
Note m: Unit number (m=0)n: Channel number (n=0)p:
SSPI
number (p=00)
Table 19-3
Slave Selection Input Function Running Clock Selection
SMRmn
register
SPSm register
Running Clock (f
MCK
)
Note
CKSmn
PRS
m13
PRS
m12
PRS
m11
PRS
m10
PRS
m03
PRS
m02
PRS
m01
PRS
m00
f
CLK
=32MHz
runtime
0
X
X
X
X
0
0
0
0
f
CLK
32MHz
X
X
X
X
0
0
0
1
f
CLK
/2
16MHz
X
X
X
X
0
0
1
0
f
CLK
/2
2
8MHz
X
X
X
X
0
0
1
1
f
CLK
/2
3
4MHz
X
X
X
X
0
1
0
0
f
CLK
/2
4
2MHz
X
X
X
X
0
1
0
1
f
CLK
/2
5
1kHz
X
X
X
X
0
1
1
0
f
CLK
/2
6
500kHz
X
X
X
X
0
1
1
1
f
CLK
/2
7
250kHz
X
X
X
X
1
0
0
0
f
CLK
/2
8
125kHz
X
X
X
X
1
0
0
1
f
CLK
/2
9
62.5kHz
X
X
X
X
1
0
1
0
f
CLK
/2
10
31.25kHz
X
X
X
X
1
0
1
1
f
CLK
/2
11
15.63kHz
X
X
X
X
1
1
0
0
f
CLK
/2
12
7.81kHz
X
X
X
X
1
1
0
1
f
CLK
/2
13
3.91kHz
X
X
X
X
1
1
1
0
f
CLK
/2
14
1.95kHz
X
X
X
X
1
1
1
1
f
CLK
/2
15
977Hz
NoteWhen you change the clock selected as f
CLK
(change the value of the system clock control register (CKC)), you
must stop the operation of the Universal Serial Communication Unit
(SCI)
(serial channel stop register
m
(
STm)=000FH) after making changes.
Note 1.X: Ignore
2.m: unit number (m=0)n: channel number (n=0).
(Transmit Clock Frequency) = {
Serial Clock (
SCLK)
Frequency
Rate
Provided by the Master
Device
}
Note
[Hz].