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Section 13 Watchdog Timer
R01UH0134EJ0400 Rev. 4.00 Page 669 of 2108
Sep 24, 2014
SH7262 Group, SH7264 Group
(2) Writing to WRCSR
WRCSR must be written by a word access to address H'FFFE0004. It cannot be written by byte
transfer or longword transfer instructions.
Procedures for writing 0 to WOVF (bit 7) and for writing to RSTE (bit 6) and RSTS (bit 5) are
different, as shown in figure 13.3.
To write 0 to the WOVF bit, the write data must be H'A5 in the upper byte and H'00 in the lower
byte. This clears the WOVF bit to 0. The RSTE and RSTS bits are not affected. To write to the
RSTE and RSTS bits, the upper byte must be H'5A and the lower byte must be the write data. The
values of bits 6 and 5 of the lower byte are transferred to the RSTE and RSTS bits, respectively.
The WOVF bit is not affected.
Address: H'FFFE0004
Address: H'FFFE0004
H'A5
H'00
15 8 7
0
H'5A
15 8 7 0
Writing 0 to the WOVF bit
Writing to the RSTE and RSTS bits
Write data
Figure 13.3 Writing to WRCSR
(3) Reading from WTCNT, WTCSR, and WRCSR
WTCNT, WTCSR, and WRCSR are read in a method similar to other registers. WTCSR is
allocated to address H'FFFE0000, WTCNT to address H'FFFE0002, and WRCSR to address
H'FFFE0004. Byte transfer instructions must be used for reading from these registers.