m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 92

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

2. APPLICATION
Fig. 2.2.11 Connection of timers and setting of division ratios [Clock function]
Fig. 2.2.12 Setting of related registers (1) [Clock function]
78
(2) Timer application example 1: Clock function (measurement of one second)
Figure 2.2.11 shows a connection of timers and a setting of division ratios, Figures 2.2.12 and 2.2.13 show a setting
of related registers, and Figure 2.2.14 shows a control procedure.
Outline : The input clock is divided by a timer so that the clock counts up every second.
Specifications :
f(X
4.19 MHz
IN
) =
T12M
T34M
• The clock f(X
• The Timer 3 interrupt request bit is checked in the main routine, and the clock is counted
• Another interrupt processing is executed in a parallel, so a timer interrupt occurs every
up when an interrupt request occurs.
244 s.
Fixed
1/16
Timer 12 mode register (Address:28
Timer 34 mode register (Address:29
Timer 1 interrupt request bit
0 0 0
0
Timer 1
IN
1/64
) = 4.19 MHz (2
3819 Group USER’S MANUAL
0 or 1
0 0 1
1
Timer 2
1/256
244 s
0
22
) is divided by a timer.
Timer 1 count : Stopped
Set to "0" at starting to count
Timer 2 count : Operating
Timer 1 count source : f(X
Timer 2 count source : Timer 1 underflow
Timer 1 output selection : I/O port
Timer 3 count : Operating
Timer 3 count source : Timer 2 underflow
Timer 3 output selection : I/O port
Timer 3
16
16
1/16
)
)
0 : No interrupt request
1 : Interrupt request
Timer 3 interrupt request bit
1 second
MITSUBISHI MICROCOMPUTER
0 or 1
IN
)/16
3819 Group
2.2 Timer