Discussion in 'Programmer's Corner' started by blue6x, Apr 18, 2005.

  1. blue6x

    Thread Starter Active Member

    Apr 6, 2005
    does anyone here knows how an 8 stage shift and store bus register, three state works... The device name particularly is HC4094F, I have very little background on bus registers and I just hope you could help me particularly that question of mine. Thanks...
  2. nanobyte

    AAC Fanatic!

    May 26, 2004
    What are Bus Registers and what do they do? Am I correct in assuming that they have something to do with the buses of a microprocessor(address,control, & data)? Do Bus Registers make up Buses like how latches are made of gates(NAND & NOR)?
  3. ram434

    New Member

    Apr 19, 2005
    Just a minor thing, why did you post this in multiple forums?
  4. pebe

    AAC Fanatic!

    Oct 11, 2004
    A bus is a conductor that links the inputs and/or outputs of several different chips so that they can communicate with one another. It may be a single wire or 8 or more wires in parallel.

    I think the simplest way to think of a bus would be to liken it to a vehicle highway. It might be a single track lane or an 8 lane highway, taking traffic from A to C or B to D. The important thing is that traffic can travel along the highway and get or off when required. But obviously, traffic can move faster on the 8 lane highway.

    With a data bus, data is sent down one bit at a time (serially) on a single wire, or 8 bits at a time on an 8 bit bus (parallel). Traffic must be controlled otherwise there would be collisions. For vehicular traffic, control is by traffic lights or barriers or similar. For data traffic this is decided by some chip that acts as the controller, and the most common device used today is a microprocessor or microcontroller.

    A simple transfer of data might occur like this. Chip A has data in an 8 bit register (an 8 bit register is a group of 8 memory cells that can hold 8 bits of data). The microcontroller (uP) sends a signal to the 'output enable' pin (OE) of chip A, which connects the register to the 8 bit bus. The bus lines now take up '0's or '1's identical to the cells of the register. The uP now sends a signal to Chip B's 'chip enable' (CE) pin. The contents of the bus are then transferred to the input of chip B and stored in a register there. Then uP removes the CE and OE signals and the transfer is complete. Note that the data is also presented to all other chips connected to the bus, but uP does not give them access to it.

    As you said, there are busses within a microprocessor connecting the various working registers with the accumilator, and with all the memory registers. The control in this case is from the CPU (central processing unit) which in turn is controlled by the programing instructions put into it.

    I hope that explanation may help.
  5. blue6x

    Thread Starter Active Member

    Apr 6, 2005
    thank you very much guys, i'm placing topics on multiple forums to be able to get the best nd the fastest possible nswer. Thank you very again guys.
  6. susi

    Active Member

    Jun 4, 2004
    ^dont do mutliple posts,it's called spamming:p