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REAL-TIME OUTPUT

7721 Group User’s Manual

10–6

10.2 Block description

10.2.3 Port P6 direction register

The pulse output pins are shared with port P6. When using these pins as pulse output pins of real-time

output, set the corresponding bits of the port P6 direction register to “1” to set these ports for the output

mode. Figure 10.2.3 shows the relationship between the port P6 direction register and the pulse output

pins.

After reset, the state of the port P6 pins are floated since these pins are in the input mode. The output

levels of the pulse output pins are undefined until Timer A0 or A1 underflows first after the data for the

timer is written. Because the pulse output data registers 0 and 1 are undefined after reset.

When these conditions should be avoided, follow the procedure “Processing of avoiding undefined output

before starting pulse output” in Figures 10.3.1 and 10.3.2.

When reading the port P6 register (address E16), the output values of the real time output pins can be read

out.

10.2.4 Timers A0 and A1

The data written into the pulse output registers 0 and 1 is output from the pulse output pins every

underflow of Timer A0 or A1. Refer to section “8.3 Timer mode” for the setting of Timers A0 and A1.

Fig. 10.2.3 Relationship between port P6 direction register and pulse output pins

Bit

Bit name

Functions

RTP00 pin

0 : Input mode

1 : Output mode

When using these pins as pulse

output pins, set the corresponding

bits to “0.”

Port P6 direction register (Address 1016)

At reset

Note: When setting these bits to “0,” the corresponding pins serve as input port

(floated) regardless of the state of the waveform output select bits (bits 0 and 1

at address 6216).

RTP01 pin

RTP02 pin

RTP03 pin

RTP10 pin

RTP11 pin

RTP12 pin

RTP13 pin

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