M30221 Просмотр технического описания (PDF) - Renesas Electronics

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M30221

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Renesas Electronics 

Reset

Mitsubishi microcomputers

M30221 Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Reset

There are two kinds of resets; hardware and software. In both cases, operation is the same after the reset.

(See “Software Reset” for details of software resets.) This section explains on hardware resets.

When the supply voltage is in the range where operation is guaranteed, a reset is effected by holding the

reset pin level “L” (0.2VCC max.) for at least 20 cycles. When the reset pin level is then returned to the “H”

level while main clock is stable, the reset status is cancelled and program execution resumes from the

address in the reset vector table.

Figure 1.6.1 shows the example reset circuit. Figure 1.6.2 shows the reset sequence.

RESET

VCC

5V

VCC

0V

5V

RESET

0V

4.0V

0.8V

Figure 1.6.1. Example reset circuit

XIN

RESET

BCLK

Address

(Internal Address signal)

More than 20 cycles are needed

BCLK 24 cycles

FFFFC16

FFFFE16

Content of reset vector

Figure 1.6.2. Reset sequence

____________

Table 1.6.1 shows the statuses of the other pins while the RESET pin level is “L”. Figures 1.6.3 and 1.6.4

show the internal status of the microcomputer immediately after the reset is cancelled.

____________

Table 1.6.1. Pin status when RESET pin level is “L”

Pin name

Status

P0, P10 to P12

P1 to P9, P13

SEG2 to SEG15

COM0 to COM3

Input port(with a pull up resistor)

Input port (floating)

“H” level is output

“H” level is output

12

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