hello guys,
i need please to know where to connect the RCLR*(pin13) and SRCLR*(pin10) from the 74HC594 should these 2 pins be connected to GND or +5V ?
datasheet in the attachment file
Shift Register SN74HC594.pdf (386 KB)
Assuming you don't want to clear the registers, they should be connected to +5V.
BillO:
Assuming you don't want to clear the registers, they should be connected to +5V.
ok thank you but what do you mean by clear ? because i never used these 2 pins before for any purpose
When you bring either pin to ground, it clears the associated register to all zeros.
BillO:
When you bring either pin to ground, it clears the associated register to all zeros.
ok thanks that is instead of clocking it to zeroes than latching it
Right.
In the datasheet (http://www.nxp.com/documents/data_sheet/74HC_HCT594.pdf) there is a "function table" at the start of page 2 - its a great idea to learn to read these tables!
The description on page 1 also mentions those two signals as "direct overriding clear" negative logic inputs.
The bar over the top of a signal name means it is "active low" or "negative logic", ie LOW means active/true, HIGH
means idle/false. This is a universal notation in logic datasheets you need to know about.
MarkT:
In the datasheet (http://www.nxp.com/documents/data_sheet/74HC_HCT594.pdf) there is a "function table" at the start of page 2 - its a great idea to learn to read these tables!The description on page 1 also mentions those two signals as "direct overriding clear" negative logic inputs.
The bar over the top of a signal name means it is "active low" or "negative logic", ie LOW means active/true, HIGH
means idle/false. This is a universal notation in logic datasheets you need to know about.
ok many thanks this is a new info about the bar 
i wrote it down