HD404358 Datasheet, PDF (61/102 Pages) Renesas Technology Corp – microcomputer has an A/D converter,

HD404358 Series
Alarm Output Function
The MCU has a built-in pulse output function called BUZZ. The pulse frequency can be selected from the
prescaler S’s outputs, and the output frequency depends on the state of port mode register C (PMRC: $025).
The duty cycle of the pulse output is fixed at 50%.
BUZZ
Alarm output
controller
Alarm output
control signal
Port mode
register A
(PMRA)
Selector
2
System ^øPER
clock
Prescaler S (PSS)
Port mode
register C
(PMRC)
Figure 49 Alarm Output Function Block Diagram
Port Mode Register C (PMRC: $025): Four-bit write-only register that selects the alarm frequencies as
shown in figure 50. It is reset to $0 by MCU reset.
Port mode register C (PMRC: $025)
Bit
Initial value
Read/Write
Bit name
3
0
W
PMRC3
2
1
0
0 Undefined 0
W
W
W
PMRC2 PMRC1 PMRC0
PMRC3 PMRC2 System Clock Divisor
0
÷2048
0
1
÷1024
0
÷512
1
1
÷256
PMRC0
0
1
Serial Clock Division Ratio
Prescaler output divided by 2
Prescaler output divided by 4
PMRC1
0
1
Output Level Control in Idle States
Low level
High level
Figure 50 Port Mode Register C (PMRC)
59