Pwc Data Buffer Register (Pwcr0 To Pwcr2) - Fujitsu MB90480 Series Hardware Manual

25.3.2 PWC Data Buffer Register (PWCR0 to PWCR2)

This section describes the configuration and functions of the PWC data buffer register
(PWCR0 to PWCR2).
■
PWC data buffer register (PWCR0 to PWCR 2)
Figure 25.3-3 shows the bit configuration of the PWC data buffer register (PWCR0 to PWCR2).
Figure 25.3-3 Bit configuration of the PWC data buffer register (PWCR0 to PWCR2)
ch.0 000079
H
ch.1 00007D
D15
H
ch.2 000081
(R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W)
H
ch.0 000078
H
ch.1 00007C
H
ch.2 000080
H
(R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W) (R/W)
The function of the PWC data buffer register (PWCR0 to 2) depends on whether the timer mode
is selected (by setting the PWCSR register bit2 to bit0 (MOD2 to 0)) or the pulse width measurement
mode is selected.
❍ Timer mode (reading/writing allowed)
In a reload timer operation (PWCSR bit3:S/C = 1), the PWC data buffer register operates as a
buffer register to store reload data. In this case, both reading and writing are allowed.
In one-shot timer operation mode (PWCSR bit3:S/C = 0), the PWC data buffer register is used
to directly access the up-count timer. In this case, both reading and writing are allowed, though
writing can only be performed when the timer is stopped. Reading is available at any time,
enabling the timer value to be read during counting.
❍ Pulse width measurement mode (Only reading allowed)
In repeated measurement mode (PWCSR bit3: S/C = 1), the PWC data buffer register operates
as a buffer register to store the results of previous measurement.
In this case, only reading is allowed. Write operations do not change the value of the register.
In one-shot mode (PWCSR bit3: S/C = 0), the PWC data buffer register is used to directly
access the up-count timer.
In this case, only reading is allowed. Write operations do not change the value of the register.
Reading is available at any time, enabling the timer value to be read during counting. After the
measurement ends, the PWC data buffer register stores the measurement result.
Note:
This register can be accessed only via word transfer instructions. At reset, the register is initialized
to "0000 ".
H
15 14 13 12
D14 D13 D12
(0) (0) (0) (0)
7 6 5 4
D7 D6 D5 D4
(0) (0) (0) (0)
CHAPTER 25 PWC TIMER (ONLY MB90485 SERIES)
11 10 9 8
D11 D10 D9 D8
(0) (0) (0) (0)
3 2 1 0
D3 D2 D1 D0
(0) (0) (0) (0)
PWCR
PWC data buffer register
Read/write
Initial value
PWCR
PWC data buffer register
Read/write
Initial value
525