Fujitsu MB89950 Series, Hardware Manual

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CHAPTER 8 PULSE WIDTH COUNT TIMER (PWC)
8.3.3 PWC Reload Buffer Register (RLBR)
The PWC reload buffer register (RLBR) functions as a reload register for the interval
timer function and as a measurement value storage register for the pulse width
measurement function.
■
PWC reload buffer register (RLBR)
Figure 8.3-5 "PWC reload buffer register (RLBR)" shows the bit structure of the PWC reload buffer
register.
Figure 8.3-5 PWC reload buffer register (RLBR)
●
For interval timer function
The register functions as a reload register, specifying the interval time.
The counter starts to count down from the set value written in this register when counter operation is
enabled (PCR1: EN = "1").
In reload timer mode, the RLBR register value is reloaded to the counter and the counter continues
counting down when a counter value underflows (01
H
--> 00
H
). If a value is written to the RLBR register
during counter operation, the new value applies from the next time the counter is reloaded due to an
underflow (01
H
--> 00
H
).
Reference:
The setting value of the RLBR register for the interval timer function is calculated as follows:
RLBR register value = interval time/(count clock cycle x instruction cycle)
Address Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Initial value
0016
H
XXXXXXXX
B
R/W R/W R/W R/W R/W R/W R/W R/W
……For the interval timer function
R R R R R R R R
……For the pulse width measurement function
R/W: Readable and writable
R : Read-only
X : Indeterminate