Overview Of The U-Timer - Fujitsu FR60 Hardware Manual

CHAPTER 8 U-TIMER
8.1

Overview of the U-TIMER

This section provides an overview and a block diagram of the U-TIMER (16-bit timer for
UART baud rate generation).
■ Overview of the U-TIMER
The U-TIMER is a 16-bit timer used to generate the baud rate for the UART. Use a combination
of a chip operating frequency and a reload value of the U-TIMER to specify a baud rate.
The U-TIMER, which generates an interrupt upon a counter underflow, can be used as an
interval timer.
The MB91301 series has three built-in U-TIMER channels. When used as an interval timer, two
sets of U-TIMERs can be cascaded to count a maximum interval of 2
of Channels 0 and 1 and Channels 0 and 2 can be connected in cascade fashion.
■ Block Diagram
Figure 8.1-1 shows the block diagram of U-TIMER.
(Peripheral Clock)
CLKP
underflow U-TIMER 1
308
Figure 8.1-1 Block Diagram of the U-TIMER
15
UTIMR (reload register)
15
UTIM (timer)
clock
MUX
Only channel 0
32
x φ. Only the combinations
0
load
0
underflow
f.f.
control
to UART