Figure 8.3.3 Pwc Reload Buffer Register (Rlbr) - Fujitsu F2MC-8L MB89620 Series Hardware Manual

8.3 Structure of Pulse Width Count Timer
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.
n For Buffer Register (RLBR)
Figure 8.3.3 shows the bit structure of the PWC reload buffer register.
Address
0016
H
R/W: Readable and writable
R : Read-only
X : Indeterminate
For interval timer function
l
The register functions as a reload register, specifying the interval time.
The counter starts counting-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
the RLBR register during counter operation, the new value applies from the next time the
counter is reloaded due to an underflow (01
Note: The setting value of the RLBR register for the interval timer function (when the instruction cycle is
the divide-by-four source oscillation (4/F
l For pulse width measurement function
The register is used to store the pulse width measurement value.
The counter value is transferred to this register when pulse width measurement completes on
detection of the edge specified for measurement completion.
At this time, the buffer full flag bit (PCR1: BF) and the measurement completion interrupt
request flag bit (PCR1: IR) are set to "1". Reading this register clears the BF bit to "0".
The register is read-only for the pulse width measurement function is selected.
Note: The pulse width for the pulse width measurement function (when the instruction cycle is the divide-
by-four source oscillation (4/F
168
CHAPTER 8 PULSE WIDTH COUNT TIMER (PWC)
Bit 7 Bit 6 Bit 5
R/W R/W R/W
R R R

Figure 8.3.3 PWC Reload Buffer Register (RLBR)

RLBR register value = interval time/(count clock cycle × instruction cycle)
RLBR register value) × count clock cycle × instruction cycle
Pulse width = (256
–
Bit 4 Bit 3 Bit 2 Bit 1
R/W R/W R/W R/W
R R R R
→ 00
).
H H
)) is calculated as follows:
C
)) is calculated based on the RLBR register value as follows:
C
Bit 0 Initial value
XXXXXXXX
B
R/W
......For the interval timer function
R
......For the pulse width measurement function
→ 00
). If a value is written to
H H
MB89620 series