3069RF-ZTAT Datasheet, PDF (389/1003 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER

Contention between 16TCNT Write and Overflow or Underflow: If an overflow occurs in the
T₃ state of a 16TCNT write cycle, writing takes priority and the counter is not incremented. OVF
is set to 1. The same holds for underflow. See figure 9.41.
16TCNT write cycle
T₁
T₂
T₃
φ
Address bus
16TCNT address
Internal write signal
16TCNT input clock
Overflow signal
16TCNT
OVF
H'FFFF
M
16TCNT write data
Figure 9.41 Contention between 16TCNT Write and Overflow
Rev. 5.0, 09/04, page 367 of 978