m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 107

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

Notes 1: Also refer to sections “[Precautions for timer mode]” and “[Precautions for event counter
TIMER A
7.2 Block description
Table 7.2.2 Reading from and writing to timer Ai register
Timer mode
Event counter mode
One-shot pulse mode
Pulse width modulation (PWM) mode
7-4
7.2.1 Counter and Reload register (timer Ai register)
Each of timer Ai counter and reload register consists of 16 bits.
Countdown in the counter is performed each time the count source is input. In the event counter mode,
it can also function as an up-counter.
The reload register is used to store the initial value of the counter. When a counter underflow or overflow
occurs, the reload register’s contents are reloaded into the counter.
A value is set to the counter and reload register by writing the value to the timer Ai register. Table 7.2.1
lists the memory assignment of the timer Ai register.
The value written into the timer Ai register while counting is not in progress is set to the counter and reload
register. The value written into the timer Ai register while counting is in progress is set only to the reload
register. In this case, the reload register’s updated contents are transferred to the counter at the next
reload time. The value obtained when reading out the timer Ai register varies according to the operating
mode. Table 7.2.2 lists reading from and writing to the timer Ai register.
2: When reading from and writing to the timer Ai register, perform it in a unit of 16 bits.
mode].”
Operating mode
7905 Group User’s Manual Rev.1.0
Counter value is read out.
(Note 1)
Undefined value is read out.
Table 7.2.1 Memory assignment of timer Ai register
Note: At reset, the contents of the timer Ai register
Read
Timer Ai register
Timer A0 register
Timer A1 register
Timer A2 register
Timer A3 register
Timer A4 register
Timer A5 register
Timer A6 register
Timer A7 register
Timer A8 register
Timer A9 register
are undefined.
High-order byte
Address 47
Address 49
Address 4B
Address 4D
Address 4F
Address C7
Address C9
Address CB
Address CD
Address CF
<While counting>
Written only to reload register.
<While not counting>
Written to both of the counter
and reload register.
16
16
16
16
16
16
16
16
16
16
Write
Low-order byte
Address 46
Address 48
Address 4A
Address 4C
Address 4E
Address C6
Address C8
Address CA
Address CC
Address CE
16
16
16
16
16
16
16
16
16
16