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Where are the specs?
25-05-2012, 08:53 PM,
#1
Where are the specs?
Hello there,

I am rather new to the whole Pinguino thing, so please be gentle Smile
Right now I ordered two boards to start testing (PIC32-PINGUINO-OTG), so I imagine that some of my questions will get answered after some tests.

I've been trying to find some sort of spec-sheet, but with no luck so far.
All the information I got seems to be either incomplete or difficult to get to.

For instance, information regarding:

- multiple hardware serial channels, as opposed to arduino's single serial channel - where are the pins for these?

- selectable between 3.3 and 5v, via a switch? I read this in the item description in a distributor's online store. What does this mean?

- battery supply / charger - how much current would it allow me to draw?

- the Pinguino seems to also have a 5v output - how much current can I draw from that output, and does that maximum value change when using a battery? (if the battery is 3.7v, there must be some sort of voltage boosting involved, which normally limits the current to a rather low level)

- does the board have a low voltage cut-off, to prevent the battery from discharging too much?

- what do we need to communicate with 5v devices, namely onewire devices?

These are just some of the things I'd like to know about when I come across this kind of product.

If someone knows where I can find such information, please feel free to share Smile

Thanks in advance.
Regards,
footswitch
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25-05-2012, 09:15 PM,
#2
RE: Where are the specs?
You sound like you haven't looked at the schematic or the user manual or Microchip's documentation for the chip and its family. They are all good things to consult in detail. You also don't sound to have looked at the pinguino wiki. Another good place.

John
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25-05-2012, 10:15 PM,
#3
RE: Where are the specs?
Oh, ok. Allow me to rephrase.
What I mean is, information on the practical side of things.

The manual (I believe you're referring to Olimex http://www.olimex.com/dev/DUINO/PIC32-PI...ev%20D.pdf) doesn't cover what I mentioned. It's more about its advantages, comparing to Arduino.
For instance, I see two hardware serial interfaces, when the wiki states there can be up to 9 (http://wiki.pinguino.cc/index.php/Compatibility).

Most of what I have learned so far in the world of microcontrollers is based on examples.
I suppose it's a matter of site navigation, how things are organized and/or visible. Just now I have found a "category" page, accessible from "Special pages" in the left side menu of the wiki. The way I see it, it's hidden from the user.

I know this is a developing community, and I will try to do my best at adding info as I come across it. But usually what keeps me going are demonstrations on how to interface with specific devices and whatnot Smile you know, like, "this pin goes here", "the power supply goes there", "do this to work around this common issue" and so on.

After all, I believe the filosophy is about showing the random guy (sorry for including me) how to connect the dots; then hopefully he will have some ground to build from there on.

Thanks for your feedback. I can't wait to get my hands on those boards Big Grin
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26-05-2012, 01:18 AM,
#4
RE: Where are the specs?
It's up to you how much effort you put into reading what is there already, I'm not going to post again what I already posted, it's now up to you whether to actually read it.

John
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26-05-2012, 07:58 AM,
#5
RE: Where are the specs?
Hi Footswitch

(25-05-2012, 08:53 PM)footswitch Wrote: Hello there,

I am rather new to the whole Pinguino thing, so please be gentle Smile
Right now I ordered two boards to start testing (PIC32-PINGUINO-OTG), so I imagine that some of my questions will get answered after some tests.

I've been trying to find some sort of spec-sheet, but with no luck so far.
All the information I got seems to be either incomplete or difficult to get to.

For instance, information regarding:

- multiple hardware serial channels, as opposed to arduino's single serial channel - where are the pins for these?
footswitch

http://wiki.pinguino.cc/images/a/a4/PIC3..._Table.pdf
Check this wiki page to know where are the UART pins ( U1TX, U1RX, U2TX, U2RX ).
For UART2, just use an Arduino syntax:
Serial2.begin
Serial2.printf

Uart 1 is the default used UART, Serial.begin uses the UART1.

(25-05-2012, 08:53 PM)footswitch Wrote: - selectable between 3.3 and 5v, via a switch? I read this in the item description in a distributor's online store. What does this mean?

:-) nothing. no switch to select input voltage. OTG is a 3,3V board

- battery supply / charger - how much current would it allow me to draw?
footswitch

http://blog.pinguino.cc/?p=185
Maybe this post will help you.

(25-05-2012, 08:53 PM)footswitch Wrote: - the Pinguino seems to also have a 5v output - how much current can I draw from that output, and does that maximum value change when using a battery? (if the battery is 3.7v, there must be some sort of voltage boosting involved, which normally limits the current to a rather low level)
footswitch

No, Pinguino is a 3,3V chip, so its output is 3,3V. Some pins can be configured as open drain, so you can switch 5V signal ( as you could do with a relay). In this case, the 5V Vcc is external.
With a battery, Pinguino will not generate a 5V Output.

(25-05-2012, 08:53 PM)footswitch Wrote: - does the board have a low voltage cut-off, to prevent the battery from discharging too much?
footswitch

I don't know, maybe Olimex could give a response.

(25-05-2012, 08:53 PM)footswitch Wrote: - what do we need to communicate with 5v devices, namely onewire devices?
footswitch

1wire is already implemented in Pinguino as a library.
Check the wiki to know function
http://wiki.pinguino.cc/index.php/Category:Functions

(25-05-2012, 08:53 PM)footswitch Wrote: These are just some of the things I'd like to know about when I come across this kind of product.

If someone knows where I can find such information, please feel free to share Smile

Thanks in advance.
Regards,
footswitch

Regards
JP
Reply
26-05-2012, 08:42 AM, (This post was last modified: 26-05-2012, 09:37 AM by mf01.)
#6
RE: Where are the specs?
(26-05-2012, 07:58 AM)jpmandon Wrote:
(25-05-2012, 08:53 PM)footswitch Wrote: - what do we need to communicate with 5v devices, namely onewire devices?
footswitch

1wire is already implemented in Pinguino as a library.
Check the wiki to know function
http://wiki.pinguino.cc/index.php/Category:Functions

To add to JP's reply and correct one of your assumptions, some, if not all, one-wire devices are NOT 5V devices. To quote from the Dallas/Maxim data sheet for the DS18B20 temperature sensor :-

Quote:Can Be Powered from Data Line; Power Supply Range is 3.0V to 5.5V

which is why it works fine with the Pinguino and the Pinguino 1wire library particularly if you use a direct power supply, as per the 18B20.pde example, rather than parasitic power.

Also there is a cross reference table for the PIC32 Pinguino OTG on the wiki (http://wiki.pinguino.cc/index.php/I/O_Mapping) which you might find useful.

Just as a general comment the functionality of any of the Pinguino boards is determined largely by the particular processor used and the Pinguino IDE. If trying to work out what a particular board is capable of I would suggest consulting the relevant MicroChip Family Data Sheet which gives a good overview of the processor capabilities and cross references to other more detailed data sheets covering each of the various built-in capabilities. The last version I have seen is titled "PIC32MX3XX/4XX Data Sheet" DS61143H but it would be worth checking the MicroChip website to see if there is a more recent vesion.

Regards

Hi Footswitch,

To add to my earlier post I think that your questions about how the power supply works for the PIC32 Pinguino OTG when running on battery can be answered by looking at the board schematic which is available on the Olimex website and probably also the wiki.

If you are particularly interested in battery and low power operation there is an application note on the MicroChip website that may be a good starting point - "Low Power Design Using PICmicro™ Microcontrollers" AN606.

Regards
Board = PIC32-Pinguino-OTG Rev C
OS = Linux Unbuntu 11.10 till 26 Apr 2012
OS = Linux Unbuntu 12:04 from 27 Apr 2012
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