Baud Rates Determined Using The Internal Timer (16-Bit Reload Timer 0) - Fujitsu MB90460 Series Hardware Manual

17.6.2 Baud Rates Determined Using the Internal Timer (16-bit
Reload Timer 0)
This section describes the settings used when the internal clock supplied from 16-bit
reload timer 0 is selected as the UART transfer clock. It also shows the baud rate
calculation formulas.

■ Baud Rates determined using the Internal Timer (16-bit Reload Timer 0)

Writing 110
determined using the internal timer. Any baud rate can be set by specifying a prescaler division ratio and
reload value for 16-bit reload timer 0. Figure 17.6-2 shows the baud rate selection circuit for the internal
timer.
Figure 17.6-2 Baud Rate Selection Circuit for the Internal Timer (16-bit Reload Timer 0)
16-bit reload timer output
(the frequency is specified with
a prescaler division ratio and
reload value)
●
Baud rate calculation formulas
Asynchronous baud rate =
Synchronous baud rate =
φ: Machine clock frequency
X: Division ratio for the prescaler of 16-bit reload timer 0 (2
n: Reload value for 16-bit reload timer 0 (0 to 65535)
to the CS2 to CS0 bits of the mode control register (SMR0/SMR1) selects the baud rate
B
(Synchronous or asynchronous clock selection)
X (n + 1) x 2 x 16
X (n + 1) x 2
SMR0/SMR1 : CS2 to CS0 = 110
(Selects the internal timer)
Clock selector
1/1 (synchronous)
1/16 (asynchronous)
SMR0/SMR1 : MD1
φ
bps
φ
bps
1 3
, 2 , 2
CHAPTER 17 UART
B
Baud rate
SCKI
5
)
495