GMS81508B HYNIX [Hynix Semiconductor], GMS81508B Datasheet - Page 44

• Manufacturer Part Number: GMS81508B
• Description: HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: HYNIX [Hynix Semiconductor]

HYUNDAI MicroElectronics
8-bit Event Counter Mode
In this mode, counting up is started by an external trigger.
This trigger means falling edge of the EC0 or EC1 pin in-
put. Source clock is used as an internal clock selected with
timer mode register TM0 or TM2. The contents of timer
data register TDRn (n = 0,1,2,3) are compared with the
contents of the up-counter Tn. If a match is found, an timer
interrupt request flag TnIF is generated, and the counter is
cleared to “0”. The counter is restart and count up contin-
uously by every falling edge of the ECn pin input.
The maximum frequency applied to the ECn pin is f
[Hz].
DEC. 1999 Ver 1.04
Timer 1 (T1IF)
Interrupt
T1ST
Start & Stop
T1CN
Control count
TDR1
EC n pin input
Up-counter
TDR1
T1IF interrupt
Start count
Occur interrupt
Figure 11-7 Count Operation of Timer / Event counter
0
Figure 11-6 Event Counter Mode Timing Chart
n
1
T1ST = 0
stop
2
clear & start
XIN
T1ST = 1
/2
In order to use event counter function, the bit 4, 5 of the
Port Mode Register PMR4(address 0D0
set to “1”.
After reset, the value of timer data register TDRn is unde-
fined, it should be initialized to between 1
"0"The interval period of Timer is calculated as below
equation.
disable
n-1
Period (sec)
enable
T1CN = 0
n
0
=
T1CN = 1
Occur interrupt
---------- -
f
1
XIN
1
2
GMS81508B/16B/24B
Divide Ratio
2
H
) is required to be
TDRn
H
~FF
TIME
H
not to
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