SH7206 Datasheet, PDF (743/1188 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7200 Series

Section 14 Watchdog Timer (WDT)
(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 14.3.
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.
Writing 0 to the WOVF bit
15
87
0
Address: H'FFFE0004
H'A5
H'00
Writing to the RSTE and RSTS bits
15
Address: H'FFFE0004
H'5A
87
0
Write data
Figure 14.3 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.
Rev. 3.00 Jun. 18, 2008 Page 719 of 1160
REJ09B0191-0300