C541U Datasheet, PDF (31/63 Pages) Siemens Semiconductor Group – 8 BIT CMOS MICROCONTROLLER

C541U
Interrupt System
The C541U provides seven interrupt sources with two priority levels. Five interrupts can be
generated by the on-chip peripherals (timer 0, timer 1, SSC interface, and USB module), and two
interrupts may be triggered externally (P3.2/INT0 and P3.3/INT1).
Figure 14 to 16 give a general overview of the interrupt sources and illustrate the request and
control flags which are described in the next sections.
Timer 0
Overflow
Timer 1
Overflow
P3.2 /
INT0
IT0
ITCON.0
TCON.0
ITCON.1
TF0
TCON.5 ET0 ^{000B H}
PT0
IEN0.1
IP0.1
TF1
TCON.7 ET1 ^{001B H}
PT1
IEN0.3
IP0.3
>1
IE0
TCON.1 EX0 ^{0003 H}
PX0
IEN0.0
IP0.0
Low Priority
High Priority
P3.3 /
INT1
IT1
ITCON.2
TCON.2
Bit addressable ^ITCON.3
>1
IE0
TCON.3 EX1 ^{0013 H}
PX1
IEN0.2
IP0.2
EA
IEN0.7
Request flag is cleared by hardware
Figure 14
Interrupt Request Sources (Part 1)
MCT03684
Semiconductor Group
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