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2014-07-02 - Gecko Family - d0001_Rev1.30
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Table 15.3. I
2
C Clock Mode
HFPERCLK
frequency (MHz)
Clock Low High
Ratio (CLHR)
Sm max frequency
(kHz)
Fm max frequency
(kHz)
Fm+ max frequency
(kHz)
0
93
400
1000
1
82
400
969
32
2
72
400
842
0
92
400
1000
1
81
400
848
28
2
71
400
736
0
93
400
1000
1
83
400
954
21
2
72
368
552
0
92
400
999
1
81
400
636
14
2
68
368
608
0
91
400
785
1
81
333
733
11
2
71
289
478
0
91
400
471
1
81
299
439
6.6
2
64
286
286
0
59
85
85
1
54
79
79
1.2
2
52
52
52
15.3.5 Arbitration
Arbitration is enabled by default, but can be disabled by setting the ARBDIS bit in I2Cn_CTRL. When
arbitration is enabled, the value on SDA is sensed every time the I
2
C module attempts to change its
value. If the sensed value is different than the value the I
2
C module tried to output, it is interpreted as a
simultaneous transmission by another device, and that the I
2
C module has lost arbitration.
Whenever arbitration is lost, the ARBLOST interrupt flag in I2Cn_IF is set, any lines held are released,
and the I
2
C device goes idle. If an I
2
C master loses arbitration during the transmission of an address,
another master may be trying to address it. The master therefore receives the rest of the address, and
if the address matches the slave address of the master, the master goes into either slave transmitter
or slave receiver mode.
Note
Arbitration can be lost both when operating as a master and when operating as a slave.
15.3.6 Buffers
15.3.6.1 Transmit Buffer and Shift Register
The I
2
C transmitter is double buffered through the transmit buffer and transmit shift register as shown in
Figure 15.1 (p. 174) . A byte is loaded into the transmit buffer by writing to I2Cn_TXDATA. When the
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