Chapter 12
Serial interface 0 and 1
Operation XII - 23
■ Transfer Speed Setup
Any transfer rate can be set by using baud rate timer (timer 14, timer 15 and timer 16). Table: 12.3.8 shows the
setup example of the transfer speed.
Table:12.3.8 UART Serial Interface Transfer Speed Setting Register
The value of timer base register is set as follows:
Underflow cycle = (Base register set value + 1) × Timer clock cycle
Baud rate = 1/(Underflow cycle × 16) (“16” represents 1/16 of a clock source)
therefore,
Base register set value = Timer clock frequency/(Baud rate × 16) - 1
For example, if the baud rate is 300 bps at timer clock source IOCLK/32 (Input frequency = 10 MHz, 6 multipli-
cation and IOCLK = MCLK/2), the set value is as follows:
Base register setting value = (30 × 10
6
/32) (300 × 16) - 1
=194
=x’C2
The table 12.3.9 shows the clock source with the standard rate and the set value of the base register at MCLK=60
and MHz (IOCLK=MCLK/2).
..
Transfer rate should be selected under 375 kbps.
..
Table:12.3.9 The Set Value of Transfer Speed (Register Set Value: Hexadecimal)
Setup Register Page
Serial clock source setting
(setting 1/16 of timer underflow)
SCnCTR XII-6, XII-7
Timer selection SIFCLK XII-10
Timer clock source
IOCLK/n
1 8 32 128
Transfer Speed
(bps)
300 1869 30C C2 30
960 7A0 F3 3C E
1200 61A C2 30 B
2400 30C 61 17 5
4800 186 30 B 2
9600 C2 17 5 -
19200 61 B 2 -
28800 40 7 - -
38400 30 5 - -
76800 17 2 - -
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