Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Help with IC Pin Names

Status
Not open for further replies.

PANewbie

New Member
Can anyone explain the meaning of the bars sometimes ised on IC pin names? For example, Pins 3, 18, and 19 of the Harris 82C88 Bus Controller are labeled as /S1, /S2, and /S0 respectively. (The bar for /S1 was omitted on the diagram, but was used in the pin description chart.) Pin 4 of that IC is labeled as DT-/R, Pin 5 is ALE, and Pin 6 is /AEN. Pin 17 is MCE-/PDEN. (See below picture of the 82C88 pinout diagram.)

Why do some pins have bars over their names (or parts of the names), while others do not? And why are some pins labeled differently by different manufacturers of the same IC? What specifically does the bar on the pin name indicate?
 

Attachments

  • 82c88-pinout.jpg
    82c88-pinout.jpg
    37.6 KB · Views: 345
On an input, It means that the function it serves is activated when a negative going signal is received, as opposed to a postive going signal.

Example: RST (Reset) will cause a chip reset when a positive voltage is applied to the pin. /RST will cause a chip reset when a negative voltage is applied...

If it appears on an output, it means that the output is inverted i.e... Q is the inverse of /Q (NOT Q)...

Make sence?
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top