Programming Counters in 8051 Microcontroller and displaying the counts in LCD

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Counter programming and displaying counts in LCD display

DIFFERENCE BETWEEN TIMERS AND COUNTERS:

• When using the timer/counter as a timer the registers THx and TLx increments for every machine cycle that is it obtains clock source from crystal which is connected to XTAL1 and XTAL2 pins of the Microcontroller.
• Whereas Counters require external clock source to be fed into the T0 (P3.4) and T1 (P3.5) pins of the 8051 Microcontroller.
• Rest of the operations are same for both counters and timers.

TMOD REGISTER:

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Timers/Counters Register

STEPS TO PROGRAM COUNTERS AND PRINT COUNTS IN LCD:

• Initialize the TMOD register to make it timer/counter function as a register.
• We are using only mode 1 of Timer0 so our TMOD hex value will be 0x05.
• Load the Initial value from where your counter needs to be start counting TL0=0.
• Start the Timer 0 to start counting by feeding the logic 1 to it TR0=1.
• To display the count values in LCD copy the TL0 values to a Integer, in our program we used " val ".
• The LCD cannot display a integer , so we need to convert the integer to character.
• For that purpose we use " sprintf(ch,"%u",val); "
• This will convert the Integer " val " values to character "ch".
• Feed the Character "ch" for displaying it in LCD.

CODE:

NOTE:

• The above code is capable of counting values from 0 to 65535 since combined 16 bit register (TH0 and TL0) can hold values from 0 to FFFF.
• To use a single register alter the line 37 of the code to val=TL0 , but while using this the register is capable of counting up to 256 only.