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Forum Index : Microcontroller and PC projects : Peripheral Communications Protocol Poll
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donmck Guru  Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Have just set up another poll: Maximite Peripheral Communications Protocol Poll. This time I have called them choices, as opposed to wishes, so we can easily distinguish between polls. Again, You can vote as many times as you chose on any answer.. http://www.themaximitecomputer.com/maximite-peripheral-commu nications-protocol-poll/ The poll will sort the answers into priority level from highest to lowest. If you find any silly errors, or would like to add a choice, please let me know by sending me an email. Maximite Peripheral Communications Protocol Poll. Choice 1: 26 Pin Flat Ribbon Cable. (Standard Bus). Choice 2: SPI Choice 3: RS-232 Choice 4: RS-485 Choice 6: I2C Cheers Don... https://www.dontronics.com |
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stuarts Senior Member  Joined: 15/06/2011 Location: AustraliaPosts: 199 |
Don already knows my vote is for i2c Time is nature's way of keeping everything from happening all at once. |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
I know, but did you vote like I did Stuart? 
And have you got that software going yet?
Cheers Don... https://www.dontronics.com |
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| stuarts Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 199 |
Don, I did vote, and I think I have some code running. Its a bugger without logical operations for bit manipulation. I think that just went to the top of my list of firmware priorities. I just need to put a little hardware together. That will have to wait until tomorrow night. Stuart Time is nature's way of keeping everything from happening all at once. |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
OK, thanks Stuart. Once the bit manipulation is written and compiled in the firmware, it really isn't going to worry the memory limitations of the PIC32 is it? Cheers Don... https://www.dontronics.com |
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| stuarts Senior Member Joined: 15/06/2011 Location: AustraliaPosts: 199 |
Don, unfortunately my C is very deficient, so I am working in basic until I2C is part of the firmware. The entire I2C routines are about 30 lines of basic at most and probably even less when compiled as firmware. Time is nature's way of keeping everything from happening all at once. |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Thanks Stuart. I fully understand. I was just chatting with Richard of tctec this morning. He decided to go in the direction of 26 wire cabled I/Os for now, instead of RS-485. The direction will depend on what users want of course. Here is a little of my response to him: [code] Hang on, I'll just need to adjust the steering wheel to the right a little. There we go, I'm flexible. I just switched my mind from comms to cables. Now where is that big box of Chinese cables I ordered? As I say, I may well get dog biscuits, with the email exchanges I had with China > The maximite can do 20 IO's directly after all... or as many as you like with simple shift registers, or your little micros. :-) [/code] Cheers Don... https://www.dontronics.com |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Maximite Peripheral Communications Protocol Poll As Geoff has virtually all types of communications we ever requested, working on the Maximite now, I have removed this poll. Great work Geoff. 
All of the early criticism about the Maximite not having serial comms is now well and truly outdated. I see a lot of other forum threads still saying otherwise, but I guess it will take a little time for the message to be passed on. RS-485 was the only one not now covered, but this is only a hardware extension of 232 type comms anyway. Cheers Don... https://www.dontronics.com |
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CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
RS485 needs proper driver-enable signals. Not there yet. Micromites and Maximites! - Beginning Maximite |
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jebz Regular Member  Joined: 13/06/2011 Location: AustraliaPosts: 79 |
9 Bit data would also be good for RS485. The 9th bit is to signal the address bite is attached and to wake the nodes. |
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Keith @ Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 167 |
Don Have you forgotten 1-wire or has it been implemented? Keith The more we know, the more we know we don't know ! |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Sorry Keith, it wasn't on this poll, so I deleted the poll, but it is still on the wish list. I do recall it was on the wish list twice. Cheers Don... https://www.dontronics.com |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
points noted on RS485 9 bit, and also enable. I don't know how the handshaking works on a PIC32 UART, but I'll ask and see what we can find out. Cheers Don... https://www.dontronics.com |
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| CircuitGizmos Guru Joined: 08/09/2011 Location: United StatesPosts: 1425 |
The PIC32 hardware UART has the ability to coerce the RTS pin (or DTR? I had looked it up) to be the RS485 driver enable signal. I think that solution would apply to the DM, as the DM uses HW UARTS. The MM uses bit-banged UARTS. The firmware should be changed to incorporate a chosen ENABLE line for RS485 support. Micromites and Maximites! - Beginning Maximite |
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| donmck Guru Joined: 09/06/2011 Location: AustraliaPosts: 1313 |
Just spoke with Ken Segler about this. Basically Ken said: Always planned to add 9 bit mode using the UEXT 485 board and for doing on the maximite its not a big deal just use a i/o like to control the transmit part It would be up to Geoff to add 9 bit to the software UART if he felt it was warranted. Cheers Don... https://www.dontronics.com |
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| Ray B Senior Member Joined: 16/02/2007 Location: AustraliaPosts: 219 |
Surely 1WIRE was an omission from previous list or how else would we communicate to the likes of high accuracy DS18B20 which I see as essential. RayB from Perth WA |
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| Keith W. Senior Member Joined: 09/10/2011 Location: AustraliaPosts: 118 |
Ray, You could use a DS1721 (or equiv) I2C with 3 address pins giving 8 devices on 1 bus. I think very similar 12 bit resolution and 0.5 degree accuracy etc, same manufacturer. Sure you need to run a few more wires but 1WIRE requires a lot of software. I have just purchased 10 off for $5 total. My little boards are made and I do not expect it will take long for the software. They can live on the I2C string with my RTC to give me a great logging system to the SD card. Keith W. |
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| Ray B Senior Member Joined: 16/02/2007 Location: AustraliaPosts: 219 |
Keith thanks for your valuable comments. If you can provide an example of how to achieve what you recommend that will be appreciated by all I'm sure. I'm aware of the I2C instructions now documented in MM manual but are not aware of any sample implimentation of those instructions. Alternatively the only other option I have been considering is interfacing through slave PicAxe which would be in line with a longer term idea of networking to remote PicAxe I/O then using the MM as the GUI & Master Controller. RayB from Perth WA |
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| Keith W. Senior Member Joined: 09/10/2011 Location: AustraliaPosts: 118 |
Hi Ray, There has been meantion of I2C regarding Real Time Clocks (RTC) on the forum and in a few other places. I will post my DS1721 code when I have it working.I have implimented an I2C data transfer to a Picaxe to drive a 128 by 64 LCD display, also on the Forum. I obtained the DS1721 devices from Rockby Electronics. Currently on special in lots of 10 while they last, Rockby have other I2C temperature devices also. Download the data sheet from the web which contains a discussion of I2C. They use a slightly more complicated I2C protocol than other I2C chips but easier than 1Wire which uses convoluted addressing methods. The chips are 8 pins and small but I can now construct little boards at home using a method with a laser printer and hot ironing the resultant image onto the board as a resist, I have constructed an I2C RTC board already and posted the code.Having addresses set at individual boards will make keeping track of multiple thermometers positions much easier. At present I seem to be thinking about implimenting NTSC video where we have a problem of character jitter. I have now thought of a method of determining what is jittering (I hope) but it will take a day to put the gear together. More to come when I have my thermometers working, but perhaps a few days. Keith W. |
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| Keith @ Senior Member Joined: 19/06/2011 Location: AustraliaPosts: 167 |
Keith W & Ray I'm of the opinion that 1-wire still needs to be included as it is another option for people to use ... once implemented in software/hardware it can be used and re-used forever more! Open up more capability and you open up to larger audience. Keith The more we know, the more we know we don't know ! |
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