C501G-1E SIEMENS [Siemens Semiconductor Group], C501G-1E Datasheet - Page 83

• Manufacturer Part Number: C501G-1E
• Description: 8-Bit Single-Chip Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

The timer 2 interrupt is generated by the logical OR of bit TF2 and EXF2 in register T2CON.
Neither of these flags is cleared by hardware when the service routine is vectored to. In fact, the
service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and
the bit will have to be cleared by software.
The serial port interrupt is generated by a logical OR of flag RI and TI in SFR SCON. Neither of
these flags is cleared by hardware when the service routine is vectored too. In fact, the service
routine will normally have to determine whether it was the receive interrupt flag or the transmission
interrupt flag that generated the interrupt, and the bit will have to be cleared by software.
Special Function Register T2CON (Address C8 H )
Special Function Register SCON (Address. 98 H )
Bit
TF2
EXF2
TI
RI
Semiconductor Group
Bit No.
Bit No.
C8 H
98 H
The shaded bits are not used for interrupt request control.
Function
Timer 2 Overflow Flag.
Set by a timer 2 overflow. Must be cleared by software. TF2 will not be set when
either RCLK = 1 or TCLK = 1.
Timer 2 External Flag.
Set when either a capture or reload is caused by a negative transition on T2EX and
EXEN2 = 1. When timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to
vector to the timer 2 interrupt routine. EXF2 must be cleared by software. EXF2
does not cause an interrupt in up/down counter mode (DCEN = 1, SFR T2MOD)
Serial interface transmitter interrupt flag
Set by hardware at the end of a serial data transmission. Must be cleared by
software.
Serial interface receiver interrupt flag
Set by hardware if a serial data byte has been received. Must be cleared by
software.
SM0
MSB
TF2
9F
CF
H
H
EXF2
SM1
9E
CE
H
H
RCLK
SM2
9D
CD
H
H
TCLK
REN
9C
CC
H
H
7-5
EXEN2
TB8
9B
CB
H
H
RB8
TR2
9A
CA
H
H
C/T2 CP/RL2
99
C9
TI
H
H
LSB
98
RI
Interrupt System
C8
H
Reset Value : 00 H
Reset Value : 00 H
H
T2CON
SCON
C501