TMP86FS49AIUG datasheet(105/296 Pages) TOSHIBA

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Page 89

TMP86FS49AIUG

8.3.6

Programmable Pulse Generate (PPG) Output Mode

In the programmable pulse generation (PPG) mode, an arbitrary duty pulse is generated by counting per-

formed in the internal clock. To start the timer, TC1CR<TC1S> specifies either the edge of the input pulse to

the TC1 pin or the command start. TC1CR<MPPG1> specifies whether a duty pulse is produced continuously

or not (one-shot pulse).

• When TC1CR<MPPG1> is set to “0” (Continuous pulse generation)

When a match between the up-counter and the TC1DRB value is detected after the timer starts, the

level of the PPG pin is inverted and an INTTC1 interrupt request is generated. The up-counter contin-

ues counting. When a match between the up-counter and the TC1DRA value is detected, the level of

the PPG pin is inverted and an INTTC1 interrupt request is generated. The up-counter is cleared at

this time, and then continues counting and pulse generation.

When TC1S is cleared to “00” during PPG output, the PPG pin retains the level immediately before

the counter stops.

• When TC1CR<MPPG1> is set to “1” (One-shot pulse generation)

When a match between the up-counter and the TC1DRB value is detected after the timer starts, the

level of the PPG pin is inverted and an INTTC1 interrupt request is generated. The up-counter contin-

ues counting. When a match between the up-counter and the TC1DRA value is detected, the level of

the PPG pin is inverted and an INTTC1 interrupt request is generated. TC1CR<TC1S> is cleared to

“00” automatically at this time, and the timer stops. The pulse generated by PPG retains the same

level as that when the timer stops.

Since the output level of the PPG pin can be set with TC1CR<TFF1> when the timer starts, a positive or neg-

ative pulse can be generated. Since the inverted level of the timer F/F1 output level is output to the PPG pin,

specify TC1CR<TFF1> to “0” to set the high level to the PPG pin, and “1” to set the low level to the PPG pin.

Upon reset, the timer F/F1 is initialized to “0”.

Note 1: To change TC1DRA or TC1DRB during a run of the timer, set a value sufficiently larger than the count

value of the counter. Setting a value smaller than the count value of the counter during a run of the timer

may generate a pulse different from that specified.

Note 2: Do not change TC1CR<TFF1> during a run of the timer. TC1CR<TFF1> can be set correctly only at initial-

ization (after reset). When the timer stops during PPG, TC1CR<TFF1> can not be set correctly from this

point onward if the PPG output has the level which is inverted of the level when the timer starts. (Setting

TC1CR<TFF1> specifies the timer F/F1 to the level inverted of the programmed value.) Therefore, the

timer F/F1 needs to be initialized to ensure an arbitrary level of the PPG output. To initialize the timer F/F1,

change TC1CR<TC1M> to the timer mode (it is not required to start the timer mode), and then set the PPG

mode. Set TC1CR<TFF1> at this time.

Note 3: In the PPG mode, the following relationship must be satisfied.

TC1DRA > TC1DRB

Note 4: Set TC1DRB after changing the mode of TC1M to the PPG mode.

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