Renesas PCA7429G02 Informations techniques télécharger pdf (Page 30)

SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER

and ON-SCREEN DISPLAY CONTROLLER

M37272M6/M8–XXXSP/FP, M37272MA–XXXSP

M37272E8SP/FP, M37272EFSP

MITSUBISHI MICROCOMPUTERS

Rev. 1.3

Internal clock : The serial I/O counter is set to “7” during the write

cycle into the serial I/O register (address 00EA16), and the transfer

clock goes HIGH forcibly. At each falling edge of the transfer clock

after the write cycle, serial data is output from the SOUT pin. Transfer

direction can be selected by bit 5 of the serial I/O mode register. At

each rising edge of the transfer clock, data is input from the SIN pin

and data in the serial I/O register is shifted 1 bit.

After the transfer clock has counted 8 times, the serial I/O counter

becomes “0” and the transfer clock stops at HIGH. At this time the

interrupt request bit is set to “1.”

Fig. 8.5.2 Serial I/O Timing (for LSB first)

(

)

“

”

External clock : The an external clock is selected as the clock source,

the interrupt request is set to “1” after the transfer clock has been

counted 8 counts. However, transfer operation does not stop, so the

clock should be controlled externally. Use the external clock of 1 MHz

or less with a duty cycle of 50%.

The serial I/O timing is shown in Figure 8.5.2. When using an exter-

nal clock for transfer, the external clock must be held at HIGH for

initializing the serial I/O counter. When switching between an inter-

nal clock and an external clock, do not switch during transfer. Also,

be sure to initialize the serial I/O counter after switching.

Notes 1: On programming, note that the serial I/O counter is set by writing to

the serial I/O register with the bit managing instructions, such as SEB

and CLB.

2: When an external clock is used as the synchronous clock, write trans-

mit data to the serial I/O register when the transfer clock input level is

HIGH.

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Renesas PCA7429G02 Informations techniques Page 30