h8s-2158 Renesas Electronics Corporation., h8s-2158 Datasheet - Page 436

• Manufacturer Part Number: h8s-2158
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 15 Watchdog Timer (WDT)
15.6.2
If a timer counter clock pulse is generated during the T2 state of a TCNT write cycle, the write
takes priority and the timer counter is not incremented. Figure 15.7 shows this operation.
15.6.3
If bits CKS2 to CKS0 in TCSR are written to while the WDT is operating, errors could occur in
the incrementation. Software must stop the watchdog timer (by clearing the TME bit to 0) before
changing the values of bits CKS2 to CKS0.
15.6.4
If the mode is switched from watchdog timer to interval timer, while the WDT is operating, errors
could occur in the incrementation. Software must stop the watchdog timer (by clearing the TME
bit to 0) before switching the mode.
Rev. 3.00 Jan 25, 2006 page 384 of 872
REJ09B0286-0300
Conflict between Timer Counter (TCNT) Write and Increment
Changing Values of CKS2 to CKS0 Bits
Switching between Watchdog Timer Mode and Interval Timer Mode
Address
Internal write signal
TCNT input clock
TCNT
Figure 15.7 Conflict between TCNT Write and Increment
N
TCNT write cycle
T 1
T 2
Counter write data
M