Siemens EF 88H Series Manual do Utilizador descarregar pdf (Página 61)

Semiconductor Group 6-27

On-Chip Peripheral Components

C501

Figure 6-16

Timer 2 Auto-Reload Mode (DCEN = 1)

A logic 1 at T2EX makes timer 2 count up. The timer will overflow at FFFF

and set the TF2 bit.

This overflow also causes the 16-bit value in RC2H and RC2L to be reloaded into the timer

registers, TH2 and TL2, respectively.

A logic 0 at T2EX makes timer 2 count down. Now the timer underflows when TH2 and TL2 equal

the values stored in RC2H and RC2L. The underflow sets the TF2 bit and causes FFFF

to be

reloaded into the timer registers. The EXF2 bit toggles whenever timer 2 overflows or underflows.

This bit can be used as a 17th bit of resolution if desired. In this operating mode, EXF2 does not

flag an interrupt.

Note: P1.1/T2EX is sampled during S5P2 of every machine cycle. The next increment/decrement

of timer 2 will be done during S3P1 in the next cycle.

1 2 ... 56 57 58 59 60 61 62 63 64 65 66 ... 120 121

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Siemens EF 88H Series Manual do Utilizador Página 61