Other features, Clock, Alternate card – Rainbow Electronics T89C5121 User Manual
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A/T8xC5121
4164G–SCR–07/06
Other Features
Clock
The Ck-ISO input must be in the range 1 - 5 MHz according to ISO7816.
The ISO Clock diagram and the configuration examples are shown in Figure 20.
Figure 21. Clock Diagram of the SCIB Block
Table 13. Examples of Settings for Clocks
Alternate Card
A second card named "Alternate card" can be controlled.
The Clock signal CCLK1 can be adapted to the XTAL frequency. Thanks to the clock
prescaler which can divide the frequency by 1, 2, 4 or 8. The bits ALTKPS0 and
ALTKPS1 in SCSR Register are used to set this factor.
Xtal ( MHz)
X2 CKCON0
FCLK Cpu
+ FCLK Periph
( MHz)
SCX2
Clk_ iso
(1 to 5 MHz)
4
0
2
0
2
4
1 (mode X2)
4
0
4
8
1
8
1
4
11.059
0
5.5295
1
2.7648
14.7456
0
7.3728
1
3.6864
16
0
8
1
4
20
0
10
1
5
1
2
1
Clk_cpu
Clk_iso
SCIB
F4_8MHz
0
SCX2
CKCON 1.3
Reset value = 1
FCLK_CPU
FCLK_Periph