SPI over several components.

C

Conrad, Robert

Guest
Is it possible to setup a single SPI Master, and several dozen SPI slaves on
basically the same chain?

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC. Anybody know
of a way of doing this?
 
Well I don't reccomend using an OLD PIC for new designs,
but yes I have driven 27 slaves with one 18C452.
Slave selects are a problem.

"Conrad, Robert" <robertc> wrote in message
news:vohtmqikuech43@corp.supernews.com...
Is it possible to setup a single SPI Master, and several dozen SPI slaves
on
basically the same chain?

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC. Anybody
know
of a way of doing this?
Click to expand...
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*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
|_-\<,_ Amateur Radio Operator: WA1RHP
(*)/ (*) Bicycle mobile on 145.41, 448.625 MHz

http://hamradio.cmcorp.com/inventory/Inventory.html
http://www.harvardrepeater.org
 
On Sun, 12 Oct 2003 00:38:18 -0600, "Conrad, Robert" <robertc> wrote:

Is it possible to setup a single SPI Master, and several dozen SPI slaves on
basically the same chain?
Click to expand...
At the rate you are going, you will probably solve it before you get
this answer! :)

The answer is yes, by definition. It would not be a "bus" if it could
not address multiple devices.

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC. Anybody know
of a way of doing this?
Click to expand...
If you must use a microprocessor, that is another level of learning
you will have to endure. Depending on your application this could be
as easy as the parallel port on a PC and VisualBasic. Since you seem
to already have a PIC, the documentation from Microchip is quite
extensive, and I believe that they offer a subroutine library for SPI
work.

You will also need a compiler and emulator, and probably a way to
design printed circuit boards. How you fell onto the PIC so quickly
is a bit of a mystery, and you may want to shop around before
selecting a device. Among many options, you should also consider the
Hitachi H8 and Atmel AVR parts. I recommend the CodeVisionAVR C
compiler for the AVR, which comes with an extensive SPI library and
excellent technical support.

But to answer your question from yesterday, the power-pole connectors
by Anderson are a very good industrial option, easy to use, rugged and
configurable. <<http://www.andersonpower.com/products/pp/pp.html>>

Kevin
 
Hehe, the problem is that I post a question, then play around with something
else which leads me to a whole new train of thought which gives me an answer
to my question, or a new solution that I didn't think about before.

The reason I am locked into a PIC16F74 is that my programmer supports the
PIC series, and I needed a UART and a large number of outputs. Then I ran
into this SPI setup which was an option because the PIC I already have has
support for it. =)

The asm on the PIC is pretty easy for me though. My biggest problem is
figuring out the timing/addressing issues related to UART programming, but I
believe that I worked through that finally.

Now I need to figure out how busing SPI is going to work (along with the
software interface for it.) The MAX 7301 Data sheet seems to want me to tie
DOUT to DIN on different chips, but the way my design is going to have to
work this will not be possible (as the two chips are going to be in
completely different control boxes.) and I will not be able to guarantee
that there will be chips in every socket (they are remote, and one might go
offline, so I must be able to handle this situation) I thought about tying
DOUT from each chip to a different IO pin on the PIC but that isn't possible
as I might have as many as 32 MAX7301's.

This all seems really complicated though. I really only need to control 8
outputs, and 2 inputs on each relay box. It seems like there would be a much
easier way of doing this.

The connectors you specified are still to large. I need a simple cabling
solution that can support 12 wires in a small wire/plug. Something like
RJ-11/RJ45 would be great but neither supports 12 wire connectors. I thought
about using RJ-11 connectors but it would require 64 on the control box and
that seems like it would make the box really large. I need to find a
connector that makes the back portion of the control box as small as
possible, makes finding or building cables easy, is cost effective, and can
support current loads that will drive a relay.

I hope I have confused things even worse =)

"Kevin Kilzer" <kkilzer.remove.this@mindspring.com> wrote in message
news:vtmiovocachfbulbntfg7tiu46oscgrh71@4ax.com...
On Sun, 12 Oct 2003 00:38:18 -0600, "Conrad, Robert" <robertc> wrote:

Is it possible to setup a single SPI Master, and several dozen SPI slaves
on
basically the same chain?

At the rate you are going, you will probably solve it before you get
this answer! :)

The answer is yes, by definition. It would not be a "bus" if it could
not address multiple devices.

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC. Anybody
know
of a way of doing this?

If you must use a microprocessor, that is another level of learning
you will have to endure. Depending on your application this could be
as easy as the parallel port on a PC and VisualBasic. Since you seem
to already have a PIC, the documentation from Microchip is quite
extensive, and I believe that they offer a subroutine library for SPI
work.

You will also need a compiler and emulator, and probably a way to
design printed circuit boards. How you fell onto the PIC so quickly
is a bit of a mystery, and you may want to shop around before
selecting a device. Among many options, you should also consider the
Hitachi H8 and Atmel AVR parts. I recommend the CodeVisionAVR C
compiler for the AVR, which comes with an extensive SPI library and
excellent technical support.

But to answer your question from yesterday, the power-pole connectors
by Anderson are a very good industrial option, easy to use, rugged and
configurable. <<http://www.andersonpower.com/products/pp/pp.html

Kevin
Click to expand...
 
Hi
Have a look here
http://www.microchip.com/1010/suppdoc/appnote/maestro/index.htm
Kind Regards
IC Teknik
Henrik N
"Conrad, Robert" <robertc> skrev i en meddelelse
news:vojrt6og5uk3df@corp.supernews.com...
Hehe, the problem is that I post a question, then play around with
something
else which leads me to a whole new train of thought which gives me an
answer
to my question, or a new solution that I didn't think about before.

The reason I am locked into a PIC16F74 is that my programmer supports the
PIC series, and I needed a UART and a large number of outputs. Then I ran
into this SPI setup which was an option because the PIC I already have has
support for it. =)

The asm on the PIC is pretty easy for me though. My biggest problem is
figuring out the timing/addressing issues related to UART programming, but
I
believe that I worked through that finally.

Now I need to figure out how busing SPI is going to work (along with the
software interface for it.) The MAX 7301 Data sheet seems to want me to
tie
DOUT to DIN on different chips, but the way my design is going to have to
work this will not be possible (as the two chips are going to be in
completely different control boxes.) and I will not be able to guarantee
that there will be chips in every socket (they are remote, and one might
go
offline, so I must be able to handle this situation) I thought about tying
DOUT from each chip to a different IO pin on the PIC but that isn't
possible
as I might have as many as 32 MAX7301's.

This all seems really complicated though. I really only need to control 8
outputs, and 2 inputs on each relay box. It seems like there would be a
much
easier way of doing this.

The connectors you specified are still to large. I need a simple cabling
solution that can support 12 wires in a small wire/plug. Something like
RJ-11/RJ45 would be great but neither supports 12 wire connectors. I
thought
about using RJ-11 connectors but it would require 64 on the control box
and
that seems like it would make the box really large. I need to find a
connector that makes the back portion of the control box as small as
possible, makes finding or building cables easy, is cost effective, and
can
support current loads that will drive a relay.

I hope I have confused things even worse =)

"Kevin Kilzer" <kkilzer.remove.this@mindspring.com> wrote in message
news:vtmiovocachfbulbntfg7tiu46oscgrh71@4ax.com...
On Sun, 12 Oct 2003 00:38:18 -0600, "Conrad, Robert" <robertc> wrote:

Is it possible to setup a single SPI Master, and several dozen SPI
slaves
on
basically the same chain?

At the rate you are going, you will probably solve it before you get
this answer! :)

The answer is yes, by definition. It would not be a "bus" if it could
not address multiple devices.

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC. Anybody
know
of a way of doing this?

If you must use a microprocessor, that is another level of learning
you will have to endure. Depending on your application this could be
as easy as the parallel port on a PC and VisualBasic. Since you seem
to already have a PIC, the documentation from Microchip is quite
extensive, and I believe that they offer a subroutine library for SPI
work.

You will also need a compiler and emulator, and probably a way to
design printed circuit boards. How you fell onto the PIC so quickly
is a bit of a mystery, and you may want to shop around before
selecting a device. Among many options, you should also consider the
Hitachi H8 and Atmel AVR parts. I recommend the CodeVisionAVR C
compiler for the AVR, which comes with an extensive SPI library and
excellent technical support.

But to answer your question from yesterday, the power-pole connectors
by Anderson are a very good industrial option, easy to use, rugged and
configurable. <<http://www.andersonpower.com/products/pp/pp.html

Kevin
Click to expand...
 
Problem with Maestro is that it doesn't compile here. I always get some
SPBRG value error.

Even the default module example fails to work for me. I have an email
pending to Microchip but there is no help in sight that I can find. Even
goggle didn't turn up help for this issue. =(

So for the time being I am forced to abandon these quick modules..


"Henrik Nielsen" <Henrik@ic-teknik.dk> wrote in message
news:3f8ad5f1$0$13175$ba624c82@nntp03.dk.telia.net...
Hi
Have a look here
http://www.microchip.com/1010/suppdoc/appnote/maestro/index.htm
Kind Regards
IC Teknik
Henrik N
"Conrad, Robert" <robertc> skrev i en meddelelse
news:vojrt6og5uk3df@corp.supernews.com...
Hehe, the problem is that I post a question, then play around with
something
else which leads me to a whole new train of thought which gives me an
answer
to my question, or a new solution that I didn't think about before.

The reason I am locked into a PIC16F74 is that my programmer supports
the
PIC series, and I needed a UART and a large number of outputs. Then I
ran
into this SPI setup which was an option because the PIC I already have
has
support for it. =)

The asm on the PIC is pretty easy for me though. My biggest problem is
figuring out the timing/addressing issues related to UART programming,
but
I
believe that I worked through that finally.

Now I need to figure out how busing SPI is going to work (along with the
software interface for it.) The MAX 7301 Data sheet seems to want me to
tie
DOUT to DIN on different chips, but the way my design is going to have
to
work this will not be possible (as the two chips are going to be in
completely different control boxes.) and I will not be able to guarantee
that there will be chips in every socket (they are remote, and one might
go
offline, so I must be able to handle this situation) I thought about
tying
DOUT from each chip to a different IO pin on the PIC but that isn't
possible
as I might have as many as 32 MAX7301's.

This all seems really complicated though. I really only need to control
8
outputs, and 2 inputs on each relay box. It seems like there would be a
much
easier way of doing this.

The connectors you specified are still to large. I need a simple cabling
solution that can support 12 wires in a small wire/plug. Something like
RJ-11/RJ45 would be great but neither supports 12 wire connectors. I
thought
about using RJ-11 connectors but it would require 64 on the control box
and
that seems like it would make the box really large. I need to find a
connector that makes the back portion of the control box as small as
possible, makes finding or building cables easy, is cost effective, and
can
support current loads that will drive a relay.

I hope I have confused things even worse =)

"Kevin Kilzer" <kkilzer.remove.this@mindspring.com> wrote in message
news:vtmiovocachfbulbntfg7tiu46oscgrh71@4ax.com...
On Sun, 12 Oct 2003 00:38:18 -0600, "Conrad, Robert" <robertc> wrote:

Is it possible to setup a single SPI Master, and several dozen SPI
slaves
on
basically the same chain?

At the rate you are going, you will probably solve it before you get
this answer! :)

The answer is yes, by definition. It would not be a "bus" if it could
not address multiple devices.

I want to setup my PIC16F74 as a SPI master, and then have it talk to
several MAX7301's using only the single SPI output on the PIC.
Anybody
know
of a way of doing this?

If you must use a microprocessor, that is another level of learning
you will have to endure. Depending on your application this could be
as easy as the parallel port on a PC and VisualBasic. Since you seem
to already have a PIC, the documentation from Microchip is quite
extensive, and I believe that they offer a subroutine library for SPI
work.

You will also need a compiler and emulator, and probably a way to
design printed circuit boards. How you fell onto the PIC so quickly
is a bit of a mystery, and you may want to shop around before
selecting a device. Among many options, you should also consider the
Hitachi H8 and Atmel AVR parts. I recommend the CodeVisionAVR C
compiler for the AVR, which comes with an extensive SPI library and
excellent technical support.

But to answer your question from yesterday, the power-pole connectors
by Anderson are a very good industrial option, easy to use, rugged and
configurable. <<http://www.andersonpower.com/products/pp/pp.html

Kevin
Click to expand...
 
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