Keil Logo

Peripheral Simulation

For Atmel AT89C51SND1 — Timer 0

Simulation support for this peripheral or feature is comprised of:

  • Dialog boxes which display and allow you to change peripheral configuration.

These simulation capabilities are described below.

Timer/Counter 0 Dialog

Timer/Counter 0

The Keil Debugger simulates all aspects of Timer/Counter 0. The configuration is reflected in the Timer/Counter 0 Dialog that you may open from the Peripherals Menu. You may use the controls in the dialog to override the settings configured by your target program. This allows you to learn how the timer/counter works by interactively changing the configuration settings.


  • Mode settings select the size and auto-reload functions, and set either Timer or Counter operation.
  • TCON (Timer Control Register) holds the run/stop and overflow flag for Timers 0 and 1.
  • TMOD (Timer Mode Register) holds the mode, gate cotrol and counter/timer select bits.
  • TH0 (Timer 0 - High Byte) contains the upper 8-bits of the Timer 0 value.
  • TL0 (Timer 0 - Low Byte) contains the lower 8-bits of the Timer 0 value.
  • T0 Pin is the Timer/Counter 0 pin for external input (P3.4/T0).
  • TF0 (Timer 0 Overflow Flag) is set when when Timer 0 overflows.


  • Status (Timer/Counter Status) displays the current status of the Timer/Counter.
  • TR0 (Timer 0 Run Control) is set to turn Timer 0 on, and reset to turn it off.
  • GATE (Gating Control) is set to enable a timer/counter while the INT0 flag is high and run control (TR0) is set.
  • INT0# External Interrupt 0 Input / Timer 0 Gate Control Input pin.
Get more information about the
Peripheral Simulation Capabilities
of the µVision Debugger.
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.