C501_1 Datasheet, PDF (79/121 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller

Interrupt System
C501
7 Interrupt System
The C501 provides 6 interrupt sources with two priority levels. Four interrupts can be generated by
the on-chip peripherals (timer 0, timer 1, timer 2 and serial interface), and two interrupts may be
triggered externally (P3.2/INT0 and P3.3/INT1).
This chapter shows the interrupt structure, the interrupt vectors and the interrupt related special
function registers. Figure 7-25 gives a general overview of the interrupt sources and illustrate the
request and the control flags which are described in the next sections.
Timer 0 Overflow
TF0
TCON.5
ET0
PT0
IE.1
IP.1
Timer 1 Overflow
TF1
TCON.0 _TCON.7
ET1
PT1
IE.3
IP.3
Timer 2 Overflow
TF2
1
T2CON.7
P1.1/
T2EX
EXF2
ET2
PT2
T2CON.6
IE.5
IP.5
EXEN2
T2CON.3
RI
1
USART
SCON.0
TI
ES
PS
SCON.1
IE.4
IP.4
P3.2/
INT0
IT0
TCON.0
IE0
TCON.1
EX0
PX0
IE.0
IP.0
P3.3/
INT1
IT1
TCON.2
IE1
TCON.3
EX1
EA
PX1
IE.2 IE.7
IP.2
High Priority
Low Priority
MCS01783
Figure 7-25
Interrupt Structure
Semiconductor Group
7-1