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2.4.7 Clock Signals in used for the SIM Interface
In conforming to the SIM interface, the UART clock signal within the SIM card needs to conform to the
UARTi (i=0 to 3) clock signal within the microprocessor. Two examples are given here as means of
generating a UARTi clock signal within the microprocessor.
* In the case of setting a value equal to or less than (1/256 X 1/16) in the division rate of UARTi clock
Choose f
* In the case of setting a value equal to or greater than (1/256 X 1/16) in the division rate of UARTi clock
Set the bit rate generator to "0", turn the source clock signal to timer output and set an optional value
in the timer.
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Let F be the clock signal within the SIM card and D be the bit rate adjustment factor, then the formula for
the UART clock signal becomes as follows. Figure 2.4.19 shows an example of connection.
• In the case of setting a value equal to or less than (1/256 X 1/16) in the division rate of UARTi clock
UARTi clock signal within microprocessor = UART clock within SIM card
f
x
1
Let X
generator becomes
16 x
Bit rate generator + 1
Bit rate generator = 92
Table 2.4.8 shows an example of setting in the UARTi bit rate generator.
• In the case of setting a value equal to or greater than (1/256 X 1/16) in the division rate of UARTi clock
UARTi clock signal within microprocessor = UART clock within SIM card
f
x
1
= f
x
1
Let X
set in the timer Ak counter becomes
16 x
Timer Ak counter + 1
Timer Ak counter = 464
Table 2.4.9 shows an example of setting in the timer Ak counter.
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
for the UART's source clock signal and set an optional value in the bit rate generator.
1
1
Bit rate generator + 1
= 16 MHz, timer Aj counter = 1, F = 372, and D = 1, then the value to be set in the bit rate
IN
1
x
1
x
flip-flop
Timer Ak counter + 1
1
x
Timer Aj counterr + 1
= 16 MHz, timer Aj counter = 3, bit rate generator = 0, F = 1860, and D = 1, then the value to be
IN
1
1
x
2
page 81 of 354
1
x
= f
x
1
16
Timer Aj counter + 1
1
1
1
=16 X
x
x
1 + 1
2
16
1
x
Bit rate generator + 1
1
flip-flop
x
F/D
1
1
x
x
=16 x
0 + 1
16
3 + 1
1
x flip-flop x
1
372/1
1
x
16
1
1
1
x
x
2
1860/1
2. SIM interface
1
F/D
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