7702 Datasheet, PDF (110/522 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER

TIMER A
5.4 Event counter mode
5.4.1 Setting for event counter mode
Figures 5.4.2 and 5.4.3 show an initial setting example for registers relevant to the event counter mode.
Note that when using interrupts, set up to enable the interrupts. For details, refer to “Chapter 4. INTERRUPTS.”
Selecting event counter mode and each function
b7
b0
!! 0
0 1 ^{Timer Ai mode register (i = 0 to 4)}
(Addresses 5616 to 5A16)
Selection of event counter mode
Pulse output function select bit
0: No pulse output
1: Pulse output
Count polarity select bit
0: Counts at falling edge of external signal.
1: Counts at rising edge of external signal.
Up-down switching factor select bit
0: Contents of up-down register
1: Input signal to TAiOUT pin
! : It may be either “0” or “1.”
Setting up–down register
b7
b0
Up–down register (Address 4416)
Timer A0 up–down bit
Timer A1 up–down bit
Timer A2 up–down bit
Timer A3 up–down bit
Timer A4 up–down bit
Set the corresponding up–down bit when the contents of
the up-down register are selected as the up-down
sw itching factor.
0: Down–count
1: Up–count
Timer A2 two–phase pulse signal processing select bit
Timer A3 two–phase pulse signal processing select bit
Timer A4 two–phase pulse signal processing select bit
Set the corresponding bit to “1” when the two–phase pulse
signal processing function is selected for timers A2 to A4.
0: Two–phase pulse signal processing
function disabled
1: Two–phase pulse signal processing
function enabled
Setting divide ratio
(b15)
b7
(b8)
b0 b7
Timer A0 register (Addresses 4716, 4616)
b0 ^{Timer A1 register (Addresses 4916, 4816)}
Timer A2 register (Addresses 4B16, 4A16)
Timer A3 register (Addresses 4D16, 4C16)
Timer A4 register (Addresses 4F16, 4E16)
Can be set to “0000 16” to “FFFF16” (n).
V The counter divides the count source frequency by n + 1
when down-counting, or by FFFF16 – n + 1 when up-
counting.
Continue to Figure 5.4.3 on next page.
Fig. 5.4.2 Initial setting example for registers relevant to event counter mode (1)
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7702/7703 Group User’s Manual