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BAT32G1x9 user manual | Chapter 20 Serial interface IICA
752 / 1149
Rev.1.02
20.4.2
The method of transmitting the clock is set by the IICWLn register and the IICWHn register
(1)
The method by which the master transmits the clock
Transmission clock
=
f
MCK
IICWL+IICWH+f
MCK
(
t
R
+t
F
)
At this point, the optimal setpoints for the IICWLn register and the IICWHn register are as follows:
(All setpoints are rounded to decimals)
•
Quick mode
IICWLn=
0.52
transmit clock
×f
MCK
IICWHn=
(
0.48
transmit clock
×t
R
-t
F
)×f
MCK
•
Standard mode
IICWLn=
0.47
transmit clock
×f
MCK
IICWHn=
(
0.53
transmit clock
×t
R
-t
F
)×f
MCK
•
Enhanced quick mode
IICWLn=
0.50
transmit clock
×f
MCK
IICWHn=
(
0.50
transmit clock
×t
R
-t
F
)×f
MCK
(2) How to set the slave IICWLn register and the IICWHn register
(All setpoints are rounded to decimals)
•
Quick mode
IICWLn=1.3μsf
×
MCK
IICWHn=(1.2μs–t
R
–t
F
)f
×
MCK
•
Standard mode
IICWLn=4.7μsf
×
MCK
IICWHn=(5.3μs–t
R
–t
F
)f
×
MCK
•
Enhanced quick mode
IICWLn=0,1.50μsf
×
MCK
IICWHn=(0.50μs–t
R
–t
F
)f
×
MCK
Note: 1. The maximum operating frequency of
the IICA
Operating Clock (f
MCK
) is
20MHz (Max.
).
。
The IICA
control
register
n1
(IICCTLn1
)
must only be placed when
the
f
CLK
exceeds
20MHz bit0
(PRSn) is set to
"1".
2. In the case of setting the transmission clock, the
minimum operating frequency of the f
CLK
must be paid
attention to
. The
minimum
operating frequency of the
f
CLK
of the serial interface
IICA
depends on the operating
mode.
Fast mode: f
CLK
= 3.5MHz (Min.
).
Enhanced Fast Mode: f
CLK
=10MHz(Min.
).
Standard mode: f
CLK
=1MHz(Min.
).
Remarks: 1. Because
the
rise time (t
R
)
and
fall time (t
F
) of
the SDAAn
signal and
the SCLAn
signal
differ depending
on the pull-up resistance and the routing capacitance, they must be calculated separately.
2. IICWLn:
IICA
low level width setting register
n
IICWHn:
IICA
high level width setting register
n
t
F
: The
descent time of the
SDAAn
signal and
the
SCLAn
signal