C515A_9708 Datasheet, PDF (128/182 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Interrupt System
C515A
Special Function Register T2CON (Address C8H)
Reset Value : 00H
Bit No.
C8H
MSB
CF_H
CE_H CD_H
CC_H
CB_H CA_H
T2PS I3FR I2FR T2R1 T2R0 T2CM
C9_H
T2I1
LSB
C8_H
T2I0
T2CON
Bit
I3FR
I2FR
The shaded bits are not used for interrupt control.
Function
External interrupt 3 rising/falling edge control flag
If I3FR = 0, the external interrupt 3 is activated by a falling edge at P1.0/INT3/CC0.
If I3FR = 1, the external interrupt 3 is activated by a rising edge at P1.0/INT3/CC0.
External interrupt 2 rising/falling edge control flag
If I2FR = 0, the external interrupt 2 is activated by a falling edge at P1.4/INT2.
If I2FR = 1, the external interrupt 2 is activated by a rising edge at P1.4/INT2.
The external interrupt 2 (INT2) can be either positive or negative transition-activated depending on
bit I2FR in register T2CON. The flag that actually generates this interrupt is bit IEX2 in register
IRCON. lf an interrupt 2 is generated, flag IEX2 is cleared by hardware when the service routine is
vectored to.
The external interrupt 3 (INT3) can be either positive or negative transition-activated, depending
on bit I3FR in register T2CON. The flag that actually generates this interrupt is bit IEX3 in register
IRCON. In addition, this flag will be set if a compare event occurs at pin P1.0/INT3/CC0, regardless
of the compare mode established and the transition at the respective pin. The flag IEX3 is cleared
by hardware when the service routine is vectored to.
Semiconductor Group
7-7
1997-08-01