4570 Datasheet, PDF (21/69 Pages) Renesas Technology Corp – SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
4570 Group
SINGLE-CHIP 4-BIT CMOS MICROCOMPUTER
The 4570 Group timer consists of the following circuits.
• Prescaler : frequency divider
• Timer 1 : 10-bit programmable timer with the interrupt function
and the carrier wave output auto-control function
• Timer 2 : 8-bit programmable timer with the interrupt function
• Timer 3 : 8-bit programmable timer with the interrupt function
and the carrier wave generation function
• 16-bit timer
Prescaler, timer 1, timer 2 and timer 3 can be controlled with the
timer control registers W1, W2 and W3.
16-bit timer is the free-run counter without the control register.
Each function is described below.
Table 9 Function related timers
Circuit
Structure
Count source
Frequency
dividing ratio
Use of output signal
Prescaler
Frequency divider • Instruction clock
4, 8
• Timer 1, 2 and 3 count sources
Timer 1
10-bit programmable • Prescaler output (ORCLK) 1 to 1024 • Timer 1 interrupt
binary down counter • Carrier wave generating circuit
• Carrier wave output auto-control
output (CARRY)
• Timer 2 count source
Timer 2
8-bit programmable • Prescaler output (ORCLK) 1 to 256
• Timer 2 interrupt
binary down counter • Timer 1 underflow
• Timer 3 count source
• Instruction clock
• TOUT output
• 16-bit timer underflow
Timer 3
8-bit programmable • Prescaler output (ORCLK) 1 to 256
• Timer 3 interrupt
binary down counter • Timer 2 underflow
• Timer 1 count source
• f(XIN) or f(XIN)/2
• Carrier wave
16-bit timer 16-bit fixed
• Instruction clock
65536
• Watchdog timer
dividing frequency
(15-th bit output is counted
twice.)
• Timer 2 count source
(16-bit timer underflow)
Control
register
W1
W1
(W5)
W2
W3
20