In a microcontroller, tmod and tcon are two different registers used to control the timing and operation of the internal timers.
TMOD (Timer Mode Register) is used to set the mode of operation for each of the two timers available in the microcontroller. Each timer can be set to operate in one of four modes - mode 0, mode 1, mode 2, or mode 3. These modes determine the behavior of the timer, including whether it counts up or down, how it is triggered, and how it generates interrupts.
TCON (Timer Control Register) is used to control the operation of the timers. It contains several bits that can be set or cleared to start, stop, reset, or enable interrupts for the timers. TCON also contains bits that are used to indicate whether a timer has overflowed, indicating that a certain amount of time has elapsed.
In summary, TMOD is used to set the mode of operation for each timer, while TCON is used to control the operation of the timers and to read their status. Both of these registers are important for programming the timers in a microcontroller and ensuring that they operate correctly for the desired application.