SN74HC595: what's shift registers and storage registers?

Howard Zou

Genius 12365 points

Part Number: SN74HC595

Hi,

in the datasheet we have shift register and storage register

Do I understand it correctly below?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 243220 points

Yes; the datasheet says:

The SNx4HC595 devices contain an 8-bit, serial-in, parallel-out shift register that feeds an 8-bit D-type storage register.

0 Howard Zou over 4 years ago in reply to Clemens Ladisch

TI__Genius 12365 points

Clemens,

thanks.

I wonder why the output state of QA to QH are all determined after only one clock cycle as shown below:

In my mind, QA will be determined after the first clock, QB won't be determined until the second clock, and so on.

After the first clock, the first shift register will be the same as SER, and the second shift register will be the same as the first one(which is undetermined when powered up I think).

0 Clemens Ladisch over 4 years ago in reply to Howard Zou

Guru 243220 points

Pulling SRCLR low forces all eight bits of the shift register to zero. The RCLK pulse then copies these eight bits to the storage registers.

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SN74HC595: what's shift registers and storage registers?