Mitsubishi Electric M32R Series User Manual page 365

Mitsubishi 32-bit risc single-chip microcomputers

Table of Contents

(3) Precautions to be observed when using TOP delayed single-shot output mode

The following describes precautions to be observed when using TOP delayed single-shot output

• If the counter stops due to underflow in the same clock period as the timer is enabled by

external input, the former has priority (so that the counter stops).

• If the counter stops due to underflow in the same clock period as count is enabled by writing to

the enable bit, the latter has priority (so that count is enabled).

• If the timer is enabled by external input in the same clock period as count is disabled by writing

to the enable bit, the latter has priority (so that count is disabled).

• Even when the counter overflows due to correction of counts, no interrupt is generated for the

occurrence of overflow. When the counter underflows in the subsequent down-count after

overflow, a false underflow interrupt is generated due to overcounting.

• When you read the counter immediately after reloading it pursuant to underflow, the value you

get is temporarily H'FFFF. But this counter value immediately changes to (reload value - 1) at

the next clock edge.

Counter value

Reload register

Figure 10.3.19 Counter Value Immediately after Underflow

MULTIJUNCTION TIMERS

10.3 TOP (Output-related 16-bit Timer)

Reload due to

Down-count starting

from reloaded register

During reload cycle, you always see H'FFFF,

and not the reload register value (in this case,