understanding of serial interrupt

• To use the serial communication with interrupt, we have to set ES bit along with the EA bit.
• Whenever single byte data is sent or received, the serial interrupt is generated and the TI or RI flag of SCON register goes high.
• Here, the TI or RI flag needs to be cleared explicitly in the interrupt routine (written for the Serial Interrupt).
• Registers those are used in programming of serial communication with interrupt are as follow:

TMOD

• G=0 mean, timer control by software mechanism.
• G=1 mean, timer control by hardware mechanism.
• C/T0= 0 mean, timer operation.
• C/T0= 1 mean, counter operation.

TH1 & TL1

• This is each 8 bit register used to load the value up to which timer run.
• On reaching on this value loaded in TH and TL, timer flag is raised

SCON

• REN=0 mean, receive transmit disable.
• REN=1 mean, receive transmit enable.
• TB8 & RB8 are reserved.
• TI=0 mean, transmission is continue.
•  TI=1 mean, transmission is completed.
• RI=0 mean, receiving is continue.
• RI=1 mean. receiving is completed.

TCON

• TR1=0 mean, to stop timer 1 .
• TR1=1 mean, to start timer 1.
• TR0=0 mean, to start timer 0.
• TR0=1 mean, to start timer 0.
• TF1=1 mean overflow condition occur in Timer 1.
• TF1=0 mean Timer 1 is in running condition.
• TF0=1 mean overflow condition occur in Timer 0.
• TF0=0 mean Timer 0 is in running condition.
• IT1=1 mean interrupt trigger is negative edge sensitive.
• IT1=0 mean interrupt trigger is positive edge sensitive.
• IT0=1 mean interrupt trigger is negative edge sensitive.
• IT0=0 mean interrupt trigger is positive edge sensitive.
• IE1=1 mean interrupt enable Timer 1.
• IE1=0 mean interrupt enable Timer 1.
• IE0=1 mean interrupt enable Timer 0.
• IE0=0 mean interrupt enable Timer 0.