ST90135 datasheet(111/190 Pages) STMICROELECTRONICS

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ST90158 - MULTIFUNCTION TIMER (MFT)

MULTIFUNCTION TIMER (Cont’d)

9.2.3.13 Autodiscrimination Mode

The phase between two pulses (respectively on in-

put pin B and input pin A) generates a one step up

(or down) count, so that the up/down control and

the counter clock are both external. Thus, if the ris-

ing edge of TxINB arrives when TxINA is at a low

level, the timer is incremented (no action if the ris-

ing edge of TxINB arrives when TxINA is at a high

level). If the falling edge of TxINB arrives when

TxINA is at a low level, the timer is decremented

(no action if the falling edge of TxINB arrives when

TxINA is at a high level).

Setting the UDC bit in the TCR register has no ef-

fect in this configuration.

9.2.3.14 TxINA = Trigger - TxINB = Ext. Clock

The signal applied to input pin A acts as a trigger

signal on REG0R, initiating the action for which the

ture), while the signal applied to input pin B is used

as the clock for the prescaler.

(*) The timer is in One shot mode and REG0R in

reload mode

9.2.3.15 TxINA = Ext. Clock - TxINB = Trigger

The signal applied to input pin B acts as a trigger,

performing a capture on REG1R, while the signal

applied to input pin A is used as the clock for the

prescaler.

9.2.3.16 TxINA = Trigger - TxINB = Gate

The signal applied to input pin A acts as a trigger

signal on REG0R, initiating the action for which the

ture), while the signal applied to input pin B acts as

a gate signal for the internal clock (i.e. the counter

runs only when the gate signal is at a low level).

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