Braille

[[email protected]]

Hi everyone
i have a little problem converting to braille,Braille is a system which
allows a blind person to "read" alphanumerics by feeling a pattern of
six raised dots.For the digits 0-9, only four dots are used, placed
essentially in the four corners of a square, i need to design a ciruit
that converts BCD to Braille. The table shows the correspondence
between BCD and Braille; A,B,C and D are the inputs and UL, UR, LL and
LR are the outputs
inputs outputs
A B C D | UL UR LR LL
----------------------------------------
0 0 0 0 | 0 1 1 1
0 0 0 1 | 1 0 0 0
0 0 1 0 | 1 0 0 1
0 0 1 1 | 1 1 0 0
0 1 0 0 | 1 1 1 0
0 1 0 1 | 1 0 1 0
0 1 1 0 | 1 1 0 1
0 1 1 1 | 1 1 1 1
1 0 0 0 | 1 0 1 1
1 0 0 1 | 0 1 0 1

I'm used to draw circuits with a lot of inputs but one single output,
this is a first time that i have 4 outputs, i'm very confused, any
help???? at least the output function, or how many AND, OR gates we
need????
Thank you guys!!!

 

[John Popelish]

Hi everyone
i have a little problem converting to braille,Braille is a system which
allows a blind person to "read" alphanumerics by feeling a pattern of
six raised dots.For the digits 0-9, only four dots are used, placed
essentially in the four corners of a square, i need to design a ciruit
that converts BCD to Braille. The table shows the correspondence
between BCD and Braille; A,B,C and D are the inputs and UL, UR, LL and
LR are the outputs
inputs outputs
A B C D | UL UR LR LL
----------------------------------------
0 0 0 0 | 0 1 1 1
0 0 0 1 | 1 0 0 0
0 0 1 0 | 1 0 0 1
0 0 1 1 | 1 1 0 0
0 1 0 0 | 1 1 1 0
0 1 0 1 | 1 0 1 0
0 1 1 0 | 1 1 0 1
0 1 1 1 | 1 1 1 1
1 0 0 0 | 1 0 1 1
1 0 0 1 | 0 1 0 1

I'm used to draw circuits with a lot of inputs but one single output,
this is a first time that i have 4 outputs, i'm very confused, any
help???? at least the output function, or how many AND, OR gates we
need????
Thank you guys!!!

You are certainly free to solve each of the outputs,
individually. Then look for common parts of each of those
solutions so you can share them.

You might also use a 1 of 16 decoder, and use simple gating
to code the Braille outputs from combinations of those
decoded states. For example the UL output is a NOR gate
connecting decoded states 0 and 9 states (Only outputs a low
if one or both of its inputs is a high).

Or program a 4 bit wide, 4 input ROM.

 

[Puckdropper]

You are certainly free to solve each of the outputs,
individually. Then look for common parts of each of those
solutions so you can share them.

*snip*

That's the approach we took about a month ago in my digital design class.
There's a lot of K-maps to draw... best use graph paper or a rubber stamp
with a 4x4 grid. ;-)

Puckdropper

 

[Arlet]

Hi everyone
i have a little problem converting to braille,Braille is a system which
allows a blind person to "read" alphanumerics by feeling a pattern of
six raised dots.For the digits 0-9, only four dots are used, placed
essentially in the four corners of a square, i need to design a ciruit
that converts BCD to Braille. The table shows the correspondence
between BCD and Braille; A,B,C and D are the inputs and UL, UR, LL and
LR are the outputs
inputs outputs
A B C D | UL UR LR LL
----------------------------------------
0 0 0 0 | 0 1 1 1
0 0 0 1 | 1 0 0 0
0 0 1 0 | 1 0 0 1
0 0 1 1 | 1 1 0 0
0 1 0 0 | 1 1 1 0
0 1 0 1 | 1 0 1 0
0 1 1 0 | 1 1 0 1
0 1 1 1 | 1 1 1 1
1 0 0 0 | 1 0 1 1
1 0 0 1 | 0 1 0 1

I'm used to draw circuits with a lot of inputs but one single output,
this is a first time that i have 4 outputs, i'm very confused, any
help???? at least the output function, or how many AND, OR gates we
need????
Thank you guys!!!

It depends if this is a homework question, or a real application.

If it's a homework question, they're probably looking for a reasonably
optimized solution based on the stuff that has been taught already,
such as Karnaugh maps. In that case, I would just follow the methods
for each output individually. A quick glance at the table doesn't show
any obvious optimizations you can get by combining partial terms.

If it's a real application, there's probably a microcontroller involved
somewhere, in which case it would be easiest to do the conversion in
software by a lookup table.

For a hardware implementation using the lowest parts count, I'd
recommend a small PAL, or similar programmable logic device.

 

[John Popelish]

*snip*

That's the approach we took about a month ago in my digital design class.
There's a lot of K-maps to draw... best use graph paper or a rubber stamp
with a 4x4 grid. ;-)

The sneaky part of this method is that a less than optimum
solution for one of the outputs may be best because it
contains the most reusable intermediate terms to be shared
with other outputs. Either you make an exhaustive (and
exhausting) list of all possibilities, or you hope for luck
or insight in your quest.

 

[Arlet]

The sneaky part of this method is that a less than optimum
solution for one of the outputs may be best because it
contains the most reusable intermediate terms to be shared
with other outputs. Either you make an exhaustive (and
exhausting) list of all possibilities, or you hope for luck
or insight in your quest.

The first step would be to define the optimum and the constraints. One
could optimize for speed, area, part count, low fanout, ... and use all
kinds of constraints: only 2 or 3 input gates, no XORs, only NORs, not
more than N inverters, glitch free.... the list is endless. Without
proper specification, you wouldn't even know where to start optimizing.

Of course, in the real world, these optimizations aren't of much value
anyway. Discrete gates are typically only used in the simplest of
applications where optimization is usually easy. For more complex
designs (even including OP's), you would typically use a programmable
logic device, and write down the desired outcome in a HDL, using a
table, case statement, or a unoptimized boolean expression. The tools
will do the boring work to make sure it meets the timing and area
constraints.

Karnaugh maps are mostly an academic toy. They're useful as a means to
provide insight into digital logic (as long as students understand why
and how they work), but rarely provide an optimal solution in terms of
real-life criteria.

 

[John Fields]

Hi everyone
i have a little problem converting to braille,Braille is a system which
allows a blind person to "read" alphanumerics by feeling a pattern of
six raised dots.For the digits 0-9, only four dots are used, placed
essentially in the four corners of a square, i need to design a ciruit
that converts BCD to Braille. The table shows the correspondence
between BCD and Braille; A,B,C and D are the inputs and UL, UR, LL and
LR are the outputs
inputs outputs
A B C D | UL UR LR LL
----------------------------------------
0 0 0 0 | 0 1 1 1
0 0 0 1 | 1 0 0 0
0 0 1 0 | 1 0 0 1
0 0 1 1 | 1 1 0 0
0 1 0 0 | 1 1 1 0
0 1 0 1 | 1 0 1 0
0 1 1 0 | 1 1 0 1
0 1 1 1 | 1 1 1 1
1 0 0 0 | 1 0 1 1
1 0 0 1 | 0 1 0 1

I'm used to draw circuits with a lot of inputs but one single output,
this is a first time that i have 4 outputs, i'm very confused, any
help???? at least the output function, or how many AND, OR gates we
need????
Thank you guys!!!

 

[JeffM]

I just posted a drawing for you on
alt.binaries.schematics.electronic,
but you can't access binary newsgroups through google groups,
so I'll email it to you

If you factor in high latency, the binary group can be *read* at
http://www.usenet-replayer.com/groups/alt.binaries.schematics.electronic.html

 

[[email protected]]

If you factor in high latency, the binary group can be *read* at
http://www.usenet-replayer.com/groups/alt.binaries.schematics.electronic.html

Thank you guys

 

[[email protected]]

---
I just posted a drawing for you on
alt.binaries.schematics.electronic, but you can't access binary
newsgroups through google groups, so I'll email it to you at
[email protected] as well.

John, if you please can send me that drawing again please, i will
appreciate it.
thank you

 

[John Fields]

John, if you please can send me that drawing again please, i will
appreciate it.
thank you