Baud Rate Based On The Internal Timer (16-Bit Reload Timer 0) - Fujitsu MB91150 Series Hardware Manual

15.8.2 Baud Rate Based on the Internal Timer (16-bit Reload
Timer 0)
This section shows the settings and equations for calculating the baud rate when the
internal clock from 16-bit reload timer 0 is selected as the UART transfer clock.
I Baud rate based on the internal timer (16-bit reload timer)
When the bits CS2 to CS0 of the mode register (SMR0-3) are set to 110
selected based on the internal timer. Any baud rate can be set through selection of the
prescaler division ratio and reload value of the 16-bit reload timer. Figure 15.8-2 "Baud-rate
selection circuit based on the internal timer (16-bit reload timer)" shows the baud-rate selection
circuit based on the internal timer.
Figure 15.8-2 Baud-rate selection circuit based on the internal timer (16-bit reload timer)
6-bit reload timer 0 output
frequency specified in
ccordance with the
rescaler divide-by value
nd reload value)
❍ Equation for baud-rate calculation
Asynchronous baud rate =
Synchronous baud rate =
: Machine clock frequency
X: Division ratio based on the prescaler of the 16-bit reload timer 0 (2
n: Reload value of the 16-bit reload timer 0 (0-65, 535)
SMR0-3: CS2/1/0=110
(Internal timer selection)
Clock selector
1/1 (synchronous)
1/16 (asynchronous)
SMR0-3: MD1
(Clock synchronous/asynchronous selection)
bps
X (n+1) 2 16
bps
X (n+1) 2
CHAPTER 15 UART
, the baud rate is
B
B
Baud rate
1 3 5
, 2 , 2 )
331