m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 164

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

2. APPLICATION
Fig. 2.7.6 Setting of related registers [Clock count using ZCR interrupt (without using a noise filter)]
150
2.7.3 Zero cross detection circuit application example 1
Clock count using ZCR interrupt (without using a noise filter)
Figure 2. 7. 6 shows a setting of related registers.
Outline : The clock is counted up every second by using the ZCR interrupts.
Specifications : • The noise filter is not used.
IREQ1
ICON1
IREQ1
ZCRCON
INTEDGE
Note :
Interrupt request register 1 (Address:3C
Interrupt control register 1 (Address:3E
Interrupt request register 1 (Address:3C
When changing the values of bit 0 of the zero cross detection control register and bit 1 of the
interrupt edge selection register, make sure the following contents.
1. During changeing, set bit 1 of the interrupt control register 1 to “0”.
2. After changeing, set bit 1 of the interrupt request register 1 to “0”.
Zero cross detection control register (Address:39
Interrupt edge selection register (Address:3A
• The commercial frequency (50 Hz or 60 Hz) is input.
• The clock is counted up by using the ZCR interrupts.
0 0
0
1
0
3819 Group USER’S MANUAL
1
2.7 Zero cross detection circuit
ZCR active edge : Falling edge active ( Note)
INT
ZCR interrupt request
Passing through the zero cross detection circuit ( Note)
Noise filter sampling clock : without using a noise filter
Set the INT
1
/ZCR interrupt : Enabled
16
16
16
)
)
)
1
/ZCR interrupt request bit to “0”
16
)
16
)
MITSUBISHI MICROCOMPUTER
3819 Group