generic microprocessor interface?

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
I am told to design a generic microprocessor interface for a ASIC chip.
 Since I am not familiar with what types/modes of microprocessor are
most popular, I don't  know how generic I can reach.

I am aware of there are synchronous/asychronous modes, separate or mux
address/data modes.  But I notice there are so many different families
and series.  Would somebody point me some typical families of
Microprocessor or even its datasheet?

Thanks,


Re: generic microprocessor interface?

Quoted text here. Click to load it
Most embedded processors will interface to peripherals that look like
old-style asynchronous generic RAM like the 6164 or 6264 (I'm dating
myself here).

Chip select, active low.
Read, active low.
Write, active low.
Separate address and data buses -- as many bits as you need.

Write to the chip happens on the trailing (positive) edge of the write
pulse or the CS pulse, whichever goes away first.  Read from the chip
happens for as long as read and CS are low.

Anything more specific should be preceded by a thorough survey of the
microprocessors you intend to interface to.

--

Tim Wescott
Wescott Design Services
We've slightly trimmed the long signature. Click to see the full one.
Re: generic microprocessor interface?
Quoted text here. Click to load it

How fast? Most microprocessors and microcontrollers have an SPI interface.
Where I used to work we used SPI to interface to our ASIC, and an FPGA.

Leon



Re: generic microprocessor interface?

Quoted text here. Click to load it

I think you need to decide on the width of the bus.
Is it 8 bit, 16 bit and/or 32 bit.

Address
Data
Chip Select

For 8 bit data
/RD    Read Strobe
/WR    Write strobe

For 16 bit buses, you have typically have two options

1) Byte Lane Enables
    /RD
    /WR
    /BHE    Byte High Enable
    /BLE    Byte Low Enable

    The latter two determine if the upper and/or lower byte is affected by
the access.

2) Word Read/Byte Write
    /RD        Read
    /WRH    Write High Byte Lane
    /WRL    Write Low Byte Lane

For 32 bit buses, the byte lane method is most common.

Sometime you want to add waitstates, and the wait signal needs to be either
active low or active high.

The MC68000 is a pretty strange beast, but it is more or less obsolete.
Maybe the Coldfire has the same, never checked.




Quoted text here. Click to load it



Re: generic microprocessor interface?
Quoted text here. Click to load it

For a class?

Quoted text here. Click to load it

If it's for a class, ask your instructor.

If it's for a job, run away quick.




Re: generic microprocessor interface?
Quoted text here. Click to load it

Or at least start looking for a job where you can work for
somebody with a clue.

--
Grant Edwards                   grante             Yow!  UH-OH!! We're out
                                  at               of AUTOMOBILE PARTS and
We've slightly trimmed the long signature. Click to see the full one.

Site Timeline