SH7040 Datasheet, PDF (498/923 Pages) Renesas Technology Corp – Renesas 32-Bit Single-Chip RISC Microprocessor SuperH RISC engine Family/SH7040 Series(CPU Core SH-2)

13.2.3 Reset Control/Status Register (RSTCSR)
The RSTCSR is an 8-bit readable and writable register. (The RSTCSR differs from other registers
in that it is more difficult to write. See section 13.2.4, Register Access, for details.) It controls
output of the internal reset signal generated by timer counter (TCNT) overflow and selects the
internal reset signal type. RSTCR is initialized to H'1F by input of a reset signal from the RES pin,
but is not initialized by the internal reset signal generated by the overflow of the WDT. It is
initialized to H'1F in standby mode.
Bit: 7
6
5
4
3
2
1
0
WOVF RSTE RSTS —
—
—
—
—
Initial value: 0
0
0
1
1
1
1
1
R/W: R/(W)^* R/W R/W
R
R
R
R
R
Note: * Only 0 can be written in bit 7 to clear the flag.
• Bit 7—Watchdog Timer Overflow Flag (WOVF): Indicates that the TCNT has overflowed
(H'FF–H'00) in the watchdog timer mode. It is not set in the interval timer mode.
Bit 7: WOVF
0
1
Description
No TCNT overflow in watchdog timer mode (initial value)
Cleared when software reads WOVF, then writes 0 in WOVF
Set by TCNT overflow in watchdog timer mode
• Bit 6—Reset Enable (RSTE): Selects whether to reset the chip internally if the TCNT
overflows in the watchdog timer mode.
Bit 6: RSTE
0
1
Description
Not reset when TCNT overflows (initial value). LSI not reset internally,
but TCNT and TCSR reset within WDT.
Reset when TCNT overflows
• Bit 5—Reset Select (RSTS): Selects the type of internal reset generated if the TCNT overflows
in the watchdog timer mode.
Bit 5: RSTS
0
1
Description
Power-on reset (initial value)
Manual reset
• Bits 4–0—Reserved: These bits always read as 1. The write value should always be 1.
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