1 / 8

8051 Aula 02

8051 Aula 02. Prof Afonso Ferreira Miguel. Microcontrolador 8051 (MCS-51). Timers do MCS51 Two 16-bit Counter/Timers: Up counters, can interrupt on overflow. Counts: CPU cycles (crystal/12). External input (max. half CPU rate). Four Operation Modes. Microcontrolador 8051 (MCS-51).

farrah-pennington
Download Presentation

8051 Aula 02

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 8051Aula 02 Prof Afonso Ferreira Miguel

  2. Microcontrolador 8051 (MCS-51) • Timers do MCS51 • Two 16-bit Counter/Timers: Up counters, can interrupt on overflow. • Counts: CPU cycles (crystal/12). External input (max. half CPU rate). • Four Operation Modes.

  3. Microcontrolador 8051 (MCS-51) • Timers do MCS51 • Timer Mode 0 : Emulates 8048 counter/timer (13-bits). 8-bit counter (TL0 or TL1). 5-bit prescaler (TH0 or TH1). • Timer Mode 1 : Simple 16-bit counter. • Timer Mode 2 : 8-bit auto-reload. Counter in TL0 or TL1. Reload value in TH0 or TH1. Provides a periodic flag or interrupt.

  4. Microcontrolador 8051 (MCS-51) • Timers do MCS51 • Timer Mode 3 : • Splits timer 0 into two 8-bit counter/timers. • First counter (TLO) acts like mode 0, • without prescaler. • Second counter (TH0): • Counts CPU cycles. • Uses TR1 (timer 1 run bit) as enable. • Uses TF1 (timer 1 overflow bit) as flag. • Uses Timer 1 interrupt. • Timer 1 (when timer 0 is in mode 3 ): • Counter stopped if in mode 3. • Running in mode 0, 1, or 2. • Has gate (INT1) and external input (T1), but no flag or interrupt. • May be used as a baud rate generator.

  5. C/T=0 C/T=1 Microcontrolador 8051 (MCS-51) • Timers do MCS51 – MODO 1 Osc. Osc. ÷12 Interrupt TL1 TH1 TF1 8-bits 8-bits T1 (Pin) Control TR1 Gate INT1 (Pin) The Gate input controls whether the Counter runs while gated by the interrupt signal or not.

  6. C/T=0 TH1 C/T=1 8-bits Microcontrolador 8051 (MCS-51) • Timers do MCS51 – MODO 2 Osc. Osc. ÷12 Interrupt TL1 TF1 8-bits T1 (Pin) Control TR1 Gate INT1 (Pin) The Gate input controls whether the Counter runs while gated by the interrupt signal or not.

  7. Microcontrolador 8051 (MCS-51) • Timers do MCS51 – TMOD

  8. Microcontrolador 8051 (MCS-51) • Timers do MCS51 – TCON

More Related