Semiconductor Group
7-21
1997-10-01
Interrupt System
C541U
The edge-triggered interrupt mode selection for the external interrupts is selected by bits in SFR
ITCON (External Interrupt Trigger Condition Register). The edge-trigger mode selection is defined
in a way (default value of ITCON after reset), that their function is upward compatible to the basic
external interrupt functionality of the C501.
Special Function Registers ITCON (Address 9AH)
Reset Value : XXXX1010B
Bit
Function
–
Reserved bit for future use.
IxETF
IxETR
External Interrupt Edge Trigger Mode Selection
(x=0,1 refers to INT0, INT1)
Bit No.
MSB
LSB
–
–
–
–
I1ETF
I1ETR
I0ETF
I0ETR
9AH
ITCON
7
6
5
4
3
2
1
0
INT0
INT1
IxETF
IxETR Function
0
0
INTx inputs are not sensitive for either rising or falling edge
0
1
INTx operates in rising edge-triggered mode
1
0
INTx operates in falling edge-triggered mode
(default after reset)
1
1
INTx operates in falling and rising edge-triggered mode
Summary of Contents for C541U
Page 1: ... 8 LW 026 0LFURFRQWUROOHU 8VHU V 0DQXDO http www siem ens d Sem iconductor ...
Page 7: ......
Page 21: ...Semiconductor Group 2 6 1997 10 01 Fundamental Structure C541U ...
Page 37: ...Semiconductor Group 4 6 1997 10 01 External Bus Interface C541U ...
Page 133: ...Semiconductor Group 6 88 1999 04 01 On Chip Peripheral Components C541U ...
Page 163: ...Semiconductor Group 8 8 1997 10 01 Fail Safe Mechanisms C541U ...
Page 185: ...Semiconductor Group 10 14 1997 10 01 OTP Memory Operation C541U ...