Infineon Technologies C166S V2 User Manual page 134

Class B traps are:
– Undefined Opcode
– Parity Fault
– Protection Fault
– Illegal Word Operand Access
The Class B traps share the same interrupt node and interrupt vector. The bit
addressable Trap Flag Register (TFR) allows a trap service routine to identify the trap
that caused the exception.
The Trap Flag Register TFR
Each trap function is indicated by a separate request flag. When a hardware trap occurs,
the corresponding request flag in register TFR is set to 1.
TFR
Trap Flag Register
15 14 13 12
STK STK
SOFT
NMI
OF UF BRK
rwh rwh rwh
rwh
Field
1)
NMI
1)
STKOF
1)
STKUF
1)
SOFTBRK
1)
UNDOPC
1)
PARFLT
User Manual
bSFR
11 10 9 8
0 0 0 0
r r r r
Bits Type Description
[15] rwh Non maskable interrupt flag
0
1
[14] rwh Stack overflow flag
0
1
[13] rwh Stack underflow flag
0
1
[12] rwh Software Break
0
1
[7] rwh Undefined Opcode
0
1
[4] rwh Parity Fault
0
1
Interrupt and Exception Handling
7 6 5
UND
0 0
OPC
r r
rwh
No non-maskable interrupt detected
Non-maskable interrupt detected
No stack overflow event detected
Stack overflow event detected
No stack underflow event detected
Stack underflow event detected
No software break event detected
Software break event detected
No undefined opcode event detected
Undefined opcode event detected
2)
No parity fault event detected
Parity fault event detected
5-134
User Manual
C166S V2
Reset Value: 0000
4 3 2 1
PAR PRT ILL
0
FLT FLT OPA
rwh rwh rwh
V 1.7, 2001-01
H
0
0
r r