U-Timer Operation - Fujitsu MB91319 Series Hardware Manual

CHAPTER 13 U-TIMER
13.3

U-TIMER Operation

This section describes calculation of a baud rate for the U-TIMER.
■ Calculation of Baud Rate
The UART uses the underflow flip-flop (f.f. in the block diagram shown in Figure 13.1-1) of the
corresponding U-TIMER (from U-TIMER0 to UART0, from U-TIMER1 to UART1, from U-TIMER2
to UART2, from U-TIMER3 to UART3, or from U-TIMER4 to UART4) as the clock source for baud
rates.
❍ Asynchronous (start-stop synchronization) mode
The UART uses the U-TIMER output divided by 8.
bps =
bps =
❍ CLK synchronous mode
bps =
bps =
254
φ
(2n+2) 8
φ
UCC 1=1
(2n+3) 8
φ
(2n+2)
φ
UCC 1=1
(2n+3)
n: UTIMR (reload value)
φ: Peripheral machine clock frequency
UCC 1=0
(Varies depending on the gear)
n: UTIMR (reload value)
φ: Peripheral machine clock frequency
UCC 1=0
(Varies depending on the gear)