Transfer Rate
Baud rate timer (timer 2 and timer 4) can set any transfer rate.
Tables 11-3-22, 23 show the setup example of the transfer rate. For detail of the baud rate timer setup,
refer to chapter 6. 8-bit Timer.
Table 11-3-22
Serial 0 clock source (timer output)
Timer clock source selection
Timer compare register selection
Table 11-3-23
Serial 1 clock source (timer output)
Timer clock source selection
Timer compare register selection
Timer 4 compare register is set as follows ;
overflow cycle = (set value of compare register + 1) x timer clock cycle
baud rate = 1 / (overflow cycle x 2 x 8) ("8" means that clock source is divided by 8)
therefore,
set value of compare register = timer clock frequency / (baud rate x 2 x 8) - 1
For example, if baud rate should be 300 bps at timer clock source fs/4 (fosc = 8 MHz, fs = fosc/2), set
value should be as follows ;
Set value of comapre register
Timer clock source and the set values of timer compare register at the standard rate are shown on the
following page.
Transfer rate should be selected under 300 kbps.
UART Serial Interface Transfer Rate Setup Register
Setup
UART Serial Interface Transfer Rate Setup Register
Setup
= (8 x 10
6
/ 2 / 4) / (300 x 2 x 8) - 1
= 207
= x'CF'
Chapter 11 Serial Interface 0, 1
Register
Page
SC0CKS
XI - 13
TM5MD
VI - 13
TM5OC
VI - 8
Register
Page
SC1CKS
XI - 20
TM4MD
VI - 12
TM4OC
VI - 8
XI - 51
Operation