C515A_9708 Datasheet, PDF (131/182 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Interrupt System
C515A
Special Function Register SCON (Address. 98H)
Bit No.
98H
MSB
9F_H
SM0
9E_H
SM1
9D_H
SM2
9C_H
REN
9B_H 9A_H
TB8 RB8
Reset Value : 00H
LSB
99_H 98_H
TI
RI SCON
The shaded bits are not used for interrupt control.
Bit
Function
TI
Serial interface transmitter interrupt flag
Set by hardware at the end of a serial data transmission. Must be cleared by
software.
RI
Serial interface receiver interrupt flag
Set by hardware if a serial data byte has been received. Must 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 to. 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.
Semiconductor Group
7-10
1997-08-01