Download User`s Manual 06.96 8-Bit CMOS Microcontroller http://www.siemens

On-Chip Peripheral Components
C504
Trap Enable Register
The trap enable register TREN is used to enable selectively the compare outputs of the three
CAPCOM channels for switching it into high or low level in the trap state as defined by the bits of the
COINI register. Additionally, for a general enable of the trap function, bit TRPEN must be set. The
TRF flag indicates when an low level is detected at the CTRAP input signal.
Special Function Register TRCON (Address CFH)
Bit No. MSB
7
CFH
TRPEN
6
TRF
5
4
3
Reset Value : 00H
2
1
LSB
0
TREN5 TREN4 TREN3 TREN2 TREN1 TREN0 TRCON
CAPCOM
Channel 2
CAPCOM
Channel 1
CAPCOM
Channel 0
Bit
Function
TRPEN
External CTRAP trap function enable bit
This bit is a general enable bit for the trap function of the CTRAP input
signal.
TRPEN = 0 : External trap input CTRAP is disabled (default after
reset).
TRPEN = 1 : External trap input CTRAP is enabled;
TRF
Trap flag
TRF is set by hardware if the trap function is enabled (TRPEN=1) and
the CTRAP level becomes active (low). If enabled, an interrupt is
generated when TRF is set. TRF must be reset by software.
TREN5-TREN0
Trap enable control bits
Bits at even bit positions (0,2,4) are assigned to the CCx compare
outputs. Bits at odd bit positions (1,3,5) are assigned to the COUTx
compare outputs.
TRENx = 0 : Compare channel output provides CAPCOM output
signal in trap state.
TRENx = 1 : Compare channel output is enabled to set the logic level
of the compare output CCx or COUTx in the trap state to
a logic state as defined by the corresponding bits of the
COINI register.
When writing TREN0-5, bit TRF should be set to 0. Otherwise, setting
TREN0-5 will generate a software trap interrupt.
Semiconductor Group
6-58