RM0082
LS_I2C controller
Doc ID 018672 Rev 1
629/844
28.6.11 IC_FS_SCL_LCNT
register(0x020)
The IC_FS_SCL_LCNT is a 16 bit RW register which allows to set the low period of the SCL
clock for fast-speed mode. The IC_FS_SCL_LCNT bit assignments are given in
.
Note:
1
This register can be written only when the I
2
C controller is disabled, which corresponds to
the IC_ENABLE (
) register being set to ‘b0. Write at other times has no
effect.
2
This register must be set before any I
2
C bus transaction can take place in order to ensure
proper I/O timing.
It is not necessary to configure this register if the I2C Controller is enabled as slave
28.6.12 IC_HS_SCL_HCNT register(0x024)
The IC_HS_SCL_HCNT is a 16 bit RW register which allows to set the high period of the
SCL clock for high-speed mode. The IC_HS_SCL_HCNT bit assignments are given in
Table 553.
IC_FS_SCL_LCNT register bit assignments
Bit
Name
Type
Reset
value
Description
[15:00]
IC_FS_SCL_LCNT
RW
16'h064
SCL clock low period count for fast speed.
This 16 bit field states the SCL clock low period
count for fast speed. The minimum valid value is
8, and hardware prevents that a value less than
this minimum will be written (setting 8 if
attempted). It is used in high speed mode to
send the master code and START BYTE or
general CALL.
Table 554.
IC_FS_SCL_LCNT sample calculations
I
2
C data rate - FS
(Kbps)
SCL clock
frequency
(MHz)
SCL low time
required min
(µs)
IC_FS_SCL_LCNT
(hex/decimal)
SCL low time
actual
(µs)
400
10
1.3
16‘h000D/’d13
1.30
400
25
1.3
16‘h0021/’d33
1.32
400
50
1.3
16‘h0041/’d65
1.30
400
75
1.3
16‘h0062/’d98
1.31
400
100
1.3
16‘h0082/’d130
1.30
400
125
1.3
16‘h00A3/’d163
1.30
400
1000
1.3
16‘h0514/’d1300
1.30