M16CSLASH26 datasheet(21/239 Pages) RENESAS

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Reset

Renesas Technology Corp.

M16C/26 Group

SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Under

development

Preliminary Specifications Rev. 0.9

Specifications in this manual are tentative and subject to change.

Voltage detection circuit

The voltage detection circuit has monitoring circuits to check the input voltage of the VCC pin. These

circuits monitor the the input voltage at VDET3 and VDET4. Bits VC26 and VC27 of VCR2 register are

used to enable/disable these monitoring circuits.

The VDET3 monitoring circuit is used for detecting the minimum VCC that guarantees proper chip

operation.

The VDET4 monitoring circuit can be set to detect whether the input voltage is equal to and greater or

less than VDET4 depending on the value of VC13 bit of the VCR1 register. In addition, the VDET4

monitoring circuit, if enabled, can generate an interrupt.

Figure 1.5.4. Reset circuit block

Watchdog timer control register

Symbol

Address

After reset

WDC

000F16 00?XXXXX2(Note1)

Function

Bit symbol

b4 b3

High-order bit of watchdog timer

WDC7

Bit name

Prescaler select bit

0 : Divided by 16

1 : Divided by 128

Reserved bit

Set to 0

Cold start / warm start

discrimination flag (Note 2)

0 : Cold start

1 : Warm start

WDC5

Note 2: The WDC5 bit will always be set to a 1 whenever the WDC SFR is written (regardless of value of WDC5 bit).

Note 1: The WDC5 bit is set to 0 immediately after power-on (cold start).

Figure 1.5.5. WDC register

VCR2 register

RESET

VCC

Write to WDC register

Internal power on reset

VCR1 register

Noise rejection

Internal reset

("L" active)

Internal power

supply voltage

stable time

td(S-R)

WARM/COLD

(warm or cold start)

1 shot

CM10 bit = 1

(stop mode)

WDC5 bit

VDET4 detect signal

VC13 bit

VDET3

≥ VDET4

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