serial to parallel converter

[bogdanfirst]

as the title of the topic says, i need a circuit wich should be quite simple, shoudn't use any programeble devices, and UART.
what i want to do is to get the output from the serial port of a computer and convert it to an 8 bit output. i could use the paralel port, but it is used by a printer, and it has to stay connected permanently to the computer.
the problem is that all the circuts i found used UARTs and they are not available any more(the ones that they used).
so has anybody encountered a circuit on the net that is quite simple, doesnt require many parts, and can convert from serial to parallel?
also i wnat to have another circuit that converts from an 8 bit input to a serial wich will be connected to the same port. basicly i need something that does what an UART does.
any1 got any solution?

 

[john1]

Hi Bogdanfirst,

I use DCC occasionally, both the parallel and the serial points.
The serial is very slow.
Sometimes i have to use the serial port,
and i usually allow extra time, but it always surprises me at
how slow it is.
Four hours for 60 Mb.

I don't know if you are using the same prog to send serial to the
serial port, that the DCC prog uses, or if the prog used to send
serial to the serial port is always the same whatever uses it.

I would be interested to know if the connections that you use on
the serial port are the same connections used for DCC link.

Cheers, John

 

[tansis]

You are not alone,
attached file shows shift register configs

 

[john1]

Hi,

Thanks for the diagrams,
they are pretty much as i would have thought,
except that they appear to be for four bit bytes,
unless they just drew four to represent eight,
and you have to imagine the remaining four ?

The second diagram is the one for taking serial in
and delivering parallel out, S.I.P.O.

In my mind it takes the form of the clock pulses
moving the incoming bits along one at a time,
then after eight counts, emptying them sideways into
a latch, and enabling the latch output until the
next serial pulse. (or something very similar)

I don't think the shift register needs to be re-set
as they all move along, the one at the end is lost.

With the opposite function, that is, parallel in to
serial out, the information can come in much faster
than it can be passed on, so some form of buffering
may need to be used.
Also the shift register may need to be reset after
each operation, as it may not necessarily put a zero
into locations that are 'clocked along'.
By that i mean that after the eight counts have moved
along to serial out, and the shift register is ready
to receive another eight bits, then it may not
necessarily have its locations at zero.
The incoming broadside eight bit byte would usually
transfer ones into the shift register.
It may well not transfer zeros, unless its totem-
poled. This would mean that care should be taken to
zero the shift register before the transfer of ones.

Just read up on the various chips you could use, you
will soon get the idea.

Best of luck with it,
John

 

[bogdanfirst]

thanks for the diagrams too.
the B point of the diagram is what i actually intend to do. it is a shift register. i was thinking to use a 74164. but the problem is to connect it to the serial interface on the computer, RS232. i'll keep thinking about it.
thanks for the idea, again!