Event Counter Mode - Renesas 7700 FAMILY User Manual

5.4 Event counter mode

In this mode, the timer counts an external signal. (Refer to Tables 5.4.1 and 5.4.2.) Figure 5.4.1 shows the
structures of the timer Ai mode register and timer Ai register in the event counter mode.
Table 5.4.1 Specifications of event counter mode (when not using two-phase pulse signal processing
function)
Item
Count source
Count operation
Count start condition
Count stop condition
Interrupt request occurrence timing
TAi pin function
IN
TAi pin function
OUT
Read from timer Ai register
Write to timer Ai register
External signal input to the TAi
The count source's valid edge can be selected between the falling
and the rising edges by software.
Up-count or down-count can be switched by external signal or software.
When the counter overflows or underflows, reload register's contents
are reloaded and counting continues.
When count start bit is set to "1."
When count start bit is cleared to "0."
When the counter overflows or underflows.
Count source input
Programmable I/O port, pulse output, or up-count/down-count switch
signal input
Counter value can be read out.
While counting is stopped
When a value is written to timer Ai register, it is written to both
reload register and counter.
While counting is in progress
When a value is written to timer Ai register, it is written to only reload
register. (Transferred to counter at next reload time.)
7751 Group User's Manual
TIMER A
5.4 Event counter mode
Specifications
pin
IN
5–19