m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 154

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

8.2.1 Counter and Reload register (timer Bi register)
Each of timer Bi counter and reload register consists of 16 bits and has the following functions.
(1) Functions in timer mode and event counter mode
(2) Functions in pulse period/pulse width measurement mode
used to store the initial value of the counter. When a counter underflow occurs, the reload register’s
contents are reloaded into the counter.
Table 8.2.1 lists the memory assignment of the timer Bi register.
reload register. The value written into the timer Bi 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 underflow. The counter value is read out by reading out the timer Bi register.
to retain the pulse period or pulse width measurement result. When a valid edge is input to the TBi
pin, the counter value is transferred to the reload register. In this mode, the value obtained by
reading the timer Bi register is the reload register’s contents, so that the measurement result is
obtained.
from the counter clear type and free-run type.
• In the case of the free-run type, the counter value does not become “0000
Countdown in the counter is performed each time the count source is input. The reload register is
A value is set to the counter and reload register by writing the value to the timer Bi register.
The value written into the timer Bi register while counting is not in progress is set to the counter and
Note: When reading from or writing to the timer Bi register, perform it in a unit of 16 bits. For more
Countup in the counter is performed each time the count source is input. The reload register is used
By using the count-type select bit (bit 4 at addresses 5B
The operation of the counter after the counter value is transferred to the reload register is as follows;
• In the case of the counter clear type, the counter value becomes “0000
Note: When reading from the timer Bi register, perform it in a unit of 16 bits.
with this counter value kept.
information about the value obtained by reading the timer Bi register, refer to sections
“[Precautions for timer mode]” and “[Precautions for event counter mode].”
7905 Group User’s Manual Rev.1.0
Table 8.2.1 Memory assignment of timer Bi registers
Note: At reset, the contents of the timer Bi register
Timer Bi register
Timer B0 register
Timer B1 register
Timer B2 register
are undefined.
16
to 5D
16
High-order byte
Address 51
Address 53
Address 55
), the count type can be selected
8.2 Block description
16
16
”; and counting continues.
”; and counting continues
16
16
16
TIMER B
Low-order byte
Address 50
Address 52
Address 54
16
16
16
8-3
IN