Searching \ for '[SX] Connector for SPI bus' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/ubicom/lib/io/index.htm?key=serial%2Fspi+spi
Search entire site for: 'Connector for SPI bus'.

Exact match. Not showing close matches.
PICList Thread
'[SX] Connector for SPI bus'
2006\12\27@205125 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

I'm looking to implement a SPI bus master that controls up to eight SPI slave devices. What I want to do is have these peripheral devices located some distance away from the SX master, and thus requiring a connector and an external cable. I want each connector to have 6 lines (Vdd, GND, MOSI, MISO, SCLK, and SS). The connector should have some sort of a locking mechanism to prevent accidental disconnecting, and shoud be panel-mount. The problem is that I don't know what connector to use for the SPI bus. I was thinking of using an RJ-45 connector. Is there a standard connector for the SPI bus? What connectors would be best suited for the application?

Thanks in advance for any help!

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@010002 by George Herzogn/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

SPI is intended for short distances [like inside the same chassis if not actually on the same board].  Speed is a consideration with any distance as transmission line losses and reflection of signals will come involved.

Having said that, the easiest system to impliment is 8 wire internet cable and connectors [RJ-45].  The parts are everywhere and cable is often shielded.  It still is a somewhat of a hack approach as you cannot really take advantage of the twisted pairs with SPI to reduce noise. But wire is wire and with SPI running at 100kHz or 400kHz maximum speed, it can be a good convienent resource.  If you want to run at Mhz, you may have trouble.

I suggest you buy a cable that is about twice your distance and test the SPI for reliablity with that.  If it works reliably at twice the distance, you should have little or no trouble in actual use unless you plan to have all items on the same SPI bus.  IN that case, distribution pattern needs to be considered.  Also there comes a question of having enough CS lines available for each device. For a shared bus, generally a star distribution pattern is the worst, while a daisy chain is best.

The easiest solution to resolving problems is to slow down your speed unti none exist.  SPI, unlike one-wire and I2C or One-wire, does not have an acknowledge signal to verify a byte is properly framed or other error verification scheme, so it is up to you to trap problems.

This points out the obvious, you might be better using One-wire or I2C.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162341
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@135609 by PJ Allenn/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, PJ Allen wrote:

Mr_Nuke asked...
Which option do you think would be better

I vote for using RS485 transceivers between the processor and the peripheral/s.
[This is a Poll, isn't it?  : ) ]
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162431
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@144124 by mgreenn/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, mgreen wrote:

You will have problems with high speed and distances more than a few inches.  If you use RS485, you will have better signal levels on one particular line, but the added delays through the driver/receiver will slow you down.  SPI is already a serial protocol.  An RJ-45 jack provides the mechanical and electrical connections, but you will want twisted pairs for the clock, MOSI and MISO, and SS signals with the 2nd wire of the twisted pair being ground.  You could carry Vdd and ground in a 5th twisted pair.  This isn't a standard Internet cable since it needs 5 pairs, but only 6 signal connections.  If you can combine MOSI and MISO onto one line (if the devices are half-duplex), you can manage with only 4 twisted pairs.  As pjv suggested, you'll have to experiment to see how high the speed can go reliably.  If you need to push it, you may need to incorporate some kind of error checking (like a CRC or checksum) to protect against the occasional errors.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162435
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@182943 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

I will try the RS485 transcievers, and probably incorporate some sort of delay into the slaves (They will also end up being SX chips).

As for the error check, I already thought of implementing a checksum, and some sort of ID code, so that the master won't communicate with nothing. I think the challenge now will be building the slave select circuit, since I don't want a short to disable the entire bus. I think a few high speed MOSFET's should do it though.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162454
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@191310 by Peter Van der Zeen/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hi Mr_Nuke;
Some more details would assist us in guiding you to a nice solution.

Please ??  (Hi speed comms is one of my favourites)
Cheers
Peter (pjv)
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162457
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@200527 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi pjv,

What I want to do is have an RS485 transmitter for the SCLK, MOSI, and each SS line on the master side, and a reciever for the MISO line. Each Slave will have 3 recievers (MOSI, SCLK and SS), and one transmitter(MISO). As a safety feature, I want to connect the SCLK, MOSI and MISO lines only to the adressed slave. I don't want to use a separate transmitter/reciever for each slave for the MISO, MOSI, ans SCLK lines, so I am thinking of using a multiplexer(actually, six of them in total) to connect the right slave. I don't have a schematic at this point, since I don't even know if the multiplexer will not affect the differetial signal.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162461
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\28@222246 by Peter Van der Zeen/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hi Mr_Nuke;
OK, so you don't have a schematic, could you at least sketch a functional drawing of what you think should be done, as well as a more generic one as to what you are trying to achieve ?

You are right, pushing RS485 through a (standard) multiplexer is problematic.

Cheers,
Peter (pjv)
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162471
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\29@092658 by George Herzogn/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

You don't need transcievers.  Use seperate reciever and tranciever pairs.  Maxim has these chips and can provide the PDFs with good information about network configuration.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162521
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\29@092828 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi pjv,

I've sketched an overall schematic of the project, but as for the RS485 level conversion, I am still unsure of what to do. I also thought of using 3TX and 1RX for each channel, and use the multiplexer on the TTL logic levels. I am still thinking of a solution, and I will post a fresh sketch once I figure out what I'm trying to do.


Alex.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162523
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\29@094003 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi Kramer,

Could you please post a link to the PDF files you mentioned?


Alex.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162533
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\29@125531 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi pjv,

I just finished a more detailed sketch.

The MAX 3283 has an active-low enable, which I can connect directly to the SS line. This should enable me to select only the input from the desired slave, and thus any short to an external cable will not affect or disable the bus.

I have also decided to use standard 8-pin RJ-45 connectors, and distribute the power through a separate cable. This should save me some money on the cable and connectors. Of course, any suggestions are welcome.

As for the distances, they will be at least two or three meters.


Alex.


MAX3283 datasheet: http://datasheets.maxim-ic.com/en/ds/MAX3280E-MAX3284E.pdf
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162596
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\29@145556 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi PJMonty,

The schematic only shows two wires, but one of then has a slash, with a 2 written next to it, wich means that it represents 2 lines, or wires. The other one has a slash with a 6 written next to it, which means it represents 6 wires. This is just a shorthand method to prevent the schematic from getting over-crowded. There are actually 8 lines that are used on the RJ-45 connector.


Alex.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162614
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\31@052424 by geekythingn/a
flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, geekything wrote:

Hi Mr_Nuke,
Not 100% sure what your application is, but have you considered 1-Wire? Good noise immunity over long distances, you can use Cat-5/5E/6 cabling just fine, you can use a spare pair for power or use parasite power.

(Do note: I'm talking about using Maxim/DalSemi parts are the slaves -- implementing your own slave on the SX technically violates their IP).

-marc
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162766
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)

2006\12\31@160956 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Marc,
I have considered other interfaces, unfortunately, 1-Wire and I2C are too slow for what I need. Also, because the slave SPI interface on the master processor will be driven by interrupts, I cannot accurately implement an asynchronious protocol with the peripherals, such as 1-Wire. I need to collect data from up to eight sensors (the peripheral devices), organize it, and send it to the computer as fast as possble. Each peripheral will collect and send data a few thousand times per second, the master processor will send it to the auxiliary processor, and the auxiliary processor to the computer, through a 256000 bps UART. In order to do this effectively, I need speed.

If there were an easier way, I'd certainly follow it.

Another solution might be to implement the RS232 UART @ 256000bps, and eight RS485 UARTS running at 128000 bps on a single processor, but even at 75MHz, I don't seem to have enough processing power for that. I'd really like to know if anyone thinks it's possible.

Alex.

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162833
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2006 (http://www.dotNetBB.com)


'[SX] Connector for SPI bus'
2007\01\01@005603 by Peter Van der Zeen/a
flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hi Mr_Nuke;
It's possible that this might all be done with a single or a pair of SX28.

Please describe wat you are trying to accomplish rather than how you are trying to implement it !

Please give sensor data formats or protocols, speed of updates, distances involved, organization required etc. Many of us have successfully implemented mutiple high speed interfaces in single SXes, and your requirements just might be a candidate for one of those.

You keep dangling the challenge in front of us, but you have not revealed the whole story. For us to help in any serious way, you need to describe what you are trying to accomplish in some detail.

Cheers,
Peter (pjv)
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162877
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)

2007\01\01@041352 by George Herzogn/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, George Herzog wrote:

http://pdfserv.maxim-ic.com/en/an/AN723.pdf
This may help you locate chips and resolve configuration.  Sorry about the slow response.  Taiwan's internet has really slowed since the quake and it is New Years.

I think you DON'T want RS-485.  You want RS-422 [full duplex].

---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162882
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)

2007\01\01@150504 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Hi pjv,

I'm sorry if I seemed to be too reluctant in providing information. Overall, I want to monitor the status of a reaction vesel. I need to monitor temperature, pressure, voltage, and I need to do it very fast, at least 1000 times per second. This would enable me to detect sudden state changes, and prevent explosions. I need to be able to connect up to eight sensors to a sensor module, which collects the data and sends it to the PC. Most sensor readings will be 16 bits wide.

The peripherals will consist of an actual electronic sensor, and an SX-20. The SX-20 will take the raw data from the electronic sensor, convert it to a standard unit (such as volts, KPa, or degrees K) and send it to the sensor module. Every peripheral will have to identify itself before communicating the readings. From this identification, the master will now what sensor is connected. I still don't know what protocol to use between the master and peripherals, but I willl certainly include a checksum.

The communication between the master and the computer will happen through a standard RS-232 port at 256000 bps. Every transmision will begin with a byte indicating a start (ASCII "S"), continue with eight bytes (or more if will prove to be necessary) that may contain commands and data, and two bytes that will be the sum of the data/command bytes, LSB first.

So far, I have the UART code finished, along with two 16 byte buffers, one for TX, and one for RX.


Should you have any more questions about my project, please, feel free to ask.


Sincerely,
Alex
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162940
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)

2007\01\01@195128 by Peter Van der Zeen/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Peter Van der Zee wrote:

Hello Alex;
At first when I read your response I thought... hey, this all CAN be done with a single SX, thereby eliminating the bulk of the communications and concern about who's on line etc. Then on re-reading realized that the 'raw to engineering units' conversion of 8000 or so channels per second is probably over the top. So, unless you could do those conversions in the main computer, and send only the raw, or at most , simply scaled values, then yes, you are relegated to using multiple SXes, and the associated communications.

So, is it a possibility to do those conversions in your host?

If so, then the single SX approach should work; offering 256 Kbit/S to the host, simultaneous with 8,000 internal (virtual) A/D conversions(8 or 9 bit) per second. But with unit conversion thrown in .... it's too much.

If the single processor approach could work for you, then the whole thing gets simplified tremndously.

Cheers,
Peter (pjv)
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m162964
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)

2007\01\02@124609 by Mr_Nuken/a

flavicon
face
In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Mr_Nuke wrote:

Peter,

I could handle eight simultaneous 8-bit A/D convesions @ 1 KHz and get the raw data, send it to the computer (I have about 33 available ISR cycles every 4th interrupt). The only problem is that I need a 16-bit resolution. Rethinking the system for 8-bit resolution shouldn't be hard, but if I perform the conversion in the same case as the Master processor, several problems arise:

1) I cannot automatically determine the type of sensor that is attached.

2) I cannot tell if the cable will become disconnected.

3) Sending analog values over long distances (2 or more meters in my case) can induce noise.

4) I would have to manually calibrate each sensor.


The idea of having a SX control each sensor was that I could avoid all these problems, but, most importantly, have the ability to auto-calibrate each sensor. Although more complex and expensive at design time, It becomes easier to use, and prevents problems, such as connecting a sensor in the wrong place.


Yes, it would be possible to do the conversions in the computer, or even master processor, but I prefer the SX/sensor apporach. Imagine having the wrong sensor hooked up, and not realizing it until something goes wrong. It is unlikely, but possible.


Sincerely,
Alex
---------- End of Message ----------

You can view the post on-line at:
http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=162334#m163080
Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com
The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2007 (http://www.dotNetBB.com)

More... (looser matching)
- Last day of these posts
- In 2007 , 2008 only
- Today
- New search...