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Topic: Mega Junior,1284 (Read 21587 times) previous topic - next topic

jbaum81

Apr 01, 2013, 09:18 am Last Edit: Apr 04, 2013, 08:30 pm by jbaum81 Reason: 1
Hello Everyone,

For a bunch of long winded reasons I've really been enjoying the 1284 as an Arduino lately. Because of this I've decided to design 3 different Arduino compatible devices based on the 1284.

The first two "Mega Junior, 1284" and "Mega Junior, 1284 SMD" are the same layout as the UNO, and both have the FT232RL chip onboard.

The "Mega Junior, 1284" has a socket for a removable chip in 40 pin DIP format and the circuitry is laid out to maintain compatibility to the pinout of the Sanguino, and maniacbugs mighty 1284. (Hope I got that right).

The "Mega junior, 1284 SMD" uses the 44pin QFP version of the 1284 and is completely custom in the way of pinout and is designed to be as compatible as possible with the Arduino uno pin locations. For the initial revision of this board I've chosen to keep programming pins and interrupts in the proper location at the sacrifice of two properly placed pwm ports.

The "Mega Junior, 1284 BB" is designed as a breadboard model and also has onboard FT232RL and all the other features one might expect of an arduino.

In addition to the boards I will be maintaining repository for all source designs and a easy to install version of optiboot which will include firmwares for 8,16, and 20mhz for my 3 boards, AND all of the other common boards of utilizing the 1284. This project is of course open source, and I'm doing this to share with the community what I've done for myself.

The only board currently tested is the "Mega Junior, 1284".

If your interested in one and dont want to build your own, send me a PM and I might be able to get one built for you, I'll try to keep a few spare boards on hand.

#####################################################################
Boot loaders Available Now!

https://code.google.com/r/jbaum81-megajunior1284/source/browse

Download latest Zip and place the contents of the root "optiboot"  folder into your Arduino hardware folder.

Includes latest ManiacBug's Mighty 1284p bootloaders with only small modifications to directory names. All other Items contained within are left untouched.

#####################################################################

jbaum81

#1
Apr 01, 2013, 09:19 am Last Edit: May 10, 2013, 07:12 am by jbaum81 Reason: 1
Mega Junior, 1284 V2

Features:
On board FT232RL usb-to-serial.
Mostly PTH components.
99% shield compatible (No PWM on D3 & D11)
8,16, or 20Mhz firmware available.
Jumper disconnect for i2c pullup resistors
Jumper disconnect for DTR/RESET
Jumper disconnect for D13 led
DPDT switch for Analog / I2C selection @ A4 & A5 pin location

Arduino Diecimila style switch for USB/EXT power.



--------------------------------------------------------------------------------------------------------------
Mega Junior,1284.

Board can be purchased from BatchPCB here: https://batchpcb.com/pcbs/110133

Features:
On board FT232RL usb-to-serial.
Mostly PTH components.
Compatible pinout to Maniacbug's Mighty 1284.
Arduino Diecimila style switch for USB/EXT power.




jbaum81

#2
Apr 01, 2013, 09:19 am Last Edit: May 27, 2013, 10:51 am by jbaum81 Reason: 1

Mega Junior, 1284 SMD

Features:
On board FT232RL usb-to-serial.
Mostly SMD components.
99% shield compatible (No PWM on D3 & D11)
8,16, or 20Mhz firmware available.
Jumper disconnect for i2c pullup resistors
Jumper disconnect for DTR/RESET
Jumper disconnect for D13 led
DPDT switch for Analog / I2C selection @ A4 & A5 pin location
Auto switch between usb and ext power




Schematic and board layouts attached.

jbaum81

#3
Apr 01, 2013, 09:19 am Last Edit: Apr 24, 2013, 07:33 am by jbaum81 Reason: 1
Reserved for Mega Junior, 1284 BB.

Tested and works as expected. However after building it I quickly came to realize that a bread board version using the DIP chip is not very feasible as it it literally spans across my breadboard leaving only open pins underneath.

The solution is to build a smaller version using the SMD chip, and dub this one the "mini". For now I'm building myself an adapter shield to break it out to be a Mega Junior, 1284 V2 or SMD compatible board. I'll share designs later once I complete.

For now it would make a great little prototype board using female headers. I currently have 3 extra built if interested PM me.

Pictures to come later.

westfw

Nice job fitting all the parts in a form-factor close to the original Arduino!

retrolefty

Great AVR chip, great idea to make it more easily available for users.

CrossRoads done a similar through hole 1284P based board and he sells the bare PCB.

So you going to pub a schematic so we can compare it to Bob's rendition?

How are you handling the +5vdc switch over from USB to external power?

No way to map the I2C pins to A4 and A5 for 328P based shield compatibility? That's a real
pain for mega boards.

Which bootloader are you going to use?

Lefty

jbaum81

#6
Apr 02, 2013, 08:53 am Last Edit: Apr 02, 2013, 09:08 am by jbaum81 Reason: 1

Great AVR chip, great idea to make it more easily available for users.

Thanks!


CrossRoads done a similar through hole 1284P based board and he sells the bare PCB.

So you going to pub a schematic so we can compare it to Bob's rendition?


Eagle Files will be made available inside this thread, this will be the main project thread, it's in it's infancy at this point.

Once fully tested I will also include a link to the board(s) @ batch PCB so you can buy a tested known working board directly from them and build your own Mega Junior, 1284.



How are you handling the +5vdc switch over from USB to external power?

The Mega Junior, 1284 is mostly all PTH and trying to stay as close to the Arduino form factor it was nearly impossible to fit the auto switching circuit. Similar to the Arduino Diecimila there is an on board swith (top left) to switch between USB/EXT power.



No way to map the I2C pins to A4 and A5 for 328P based shield compatibility? That's a real
pain for mega boards.


Originally this started out for me only before I decided to share it, Later on I may release a new revision of this board that will conform more to the R3 form factor. I did take this into account with the Mega Junior, 1284 SMD but forgot the ref voltage pin (doh!) This will be fixed in later revisions.

If there is enough of a demand from the community I will do something to move over the I2c, but you will loose analog on those ports, unless I jumper or something along those lines.  


Which bootloader are you going to use?

I'm using the latest optiboot, when available I will try to include firmwares for all other known 1284 boards to make it an easy to install one-stop=shop package for all. I've tested firmwares for 8MHz (internal clock), 16MHz & 20MHz external crystals.

jbaum81


Nice job fitting all the parts in a form-factor close to the original Arduino!



Thank you, It's actually just a tad longer than the Uno, all holes are in the same location, as well as the ext power and USB.

retrolefty



Great AVR chip, great idea to make it more easily available for users.

Thanks!


CrossRoads done a similar through hole 1284P based board and he sells the bare PCB.

So you going to pub a schematic so we can compare it to Bob's rendition?


Eagle Files will be made available inside this thread, this will be the main project thread, it's in it's infancy at this point.

Once fully tested I will also include a link to the board(s) @ batch PCB so you can buy a tested known working board directly from them and build your own Mega Junior, 1284.
I don't do cad software so if sometime in the future when you do publish a PDF of the schematic would be appreciated.


How are you handling the +5vdc switch over from USB to external power?

The Mega Junior, 1284 is mostly all PTH and trying to stay as close to the Arduino form factor it was nearly impossible to fit the auto switching circuit. Similar to the Arduino Diecimila there is an on board swith (top left) to switch between USB/EXT power.
I actually prefer a manual switch or jumper pins. The arduino auto-voltage switching is a over complex circuit that wastes board real estate for a dump feature. Bob's board uses a 3 position jumper clip. He also added a jumper clip to allow or disable the DTR auto-reset pulse, which can be very useful at times and is recommenced if you do a future revision of your board.



No way to map the I2C pins to A4 and A5 for 328P based shield compatibility? That's a real
pain for mega boards.


Originally this started out for me only before I decided to share it, Later on I may release a new revision of this board that will conform more to the R3 form factor. I did take this into account with the Mega Junior, 1284 SMD but forgot the ref voltage pin (doh!) This will be fixed in later revisions.

If there is enough of a demand from the community I will do something to move over the I2c, but you will loose analog on those ports, unless I jumper or something along those lines.

Yea it's a problem that defies a 'perfect' solution for all users in all cases. Bob's board uses jumper clips and that seems a pretty good compromise solution to me.
Lefty  



Which bootloader are you going to use?

I'm using the latest optiboot, when available I will try to include firmwares for all other known 1284 boards to make it an easy to install one-stop=shop package for all. I've tested firmwares for 8MHz (internal clock), 16MHz & 20MHz external crystals.

Don't forget to tell your future customers that the board would accept a 644P as a direct pin compatible replacement in the board, just software configuration changes, bootloader, etc.
Lefty


CrossRoads

#9
Apr 02, 2013, 02:58 pm Last Edit: Apr 02, 2013, 03:00 pm by CrossRoads Reason: 1
Here is the board Lefty is talking about.
This one was assembled by one of the users. I was thinking male jumpers at the top left for the A4/A5-SDA/SCL selection, he chose a female header.
This board also allows users to select off-board USB/Serial connectivity (such as FTDI Basic, or a CP2102 module), or onboard with a MIKROE483 (the least expensive FTDI module around) if the end usage needs full time USB access.

This other smaller SMD board is a simpler version, with an off-board FTDI type header, and no onboard regulator, good for battery powered applications (I use a 3 AA battery pack when testing) or some external power source.

Both use maniacbug's 1284 cores and Bobuino as board type.
More details on both here
http://www.crossroadsfencing.com/BobuinoRev17/

I have bare boards for both available, $6 for the larger board and $3 for the smaller, includes postage to US locations. International a bit more. PM me.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

jbaum81




Great AVR chip, great idea to make it more easily available for users.

Thanks!


CrossRoads done a similar through hole 1284P based board and he sells the bare PCB.

So you going to pub a schematic so we can compare it to Bob's rendition?


Eagle Files will be made available inside this thread, this will be the main project thread, it's in it's infancy at this point.

Once fully tested I will also include a link to the board(s) @ batch PCB so you can buy a tested known working board directly from them and build your own Mega Junior, 1284.
I don't do cad software so if sometime in the future when you do publish a PDF of the schematic would be appreciated.


How are you handling the +5vdc switch over from USB to external power?

The Mega Junior, 1284 is mostly all PTH and trying to stay as close to the Arduino form factor it was nearly impossible to fit the auto switching circuit. Similar to the Arduino Diecimila there is an on board swith (top left) to switch between USB/EXT power.
I actually prefer a manual switch or jumper pins. The arduino auto-voltage switching is a over complex circuit that wastes board real estate for a dump feature. Bob's board uses a 3 position jumper clip. He also added a jumper clip to allow or disable the DTR auto-reset pulse, which can be very useful at times and is recommenced if you do a future revision of your board.



No way to map the I2C pins to A4 and A5 for 328P based shield compatibility? That's a real
pain for mega boards.


Originally this started out for me only before I decided to share it, Later on I may release a new revision of this board that will conform more to the R3 form factor. I did take this into account with the Mega Junior, 1284 SMD but forgot the ref voltage pin (doh!) This will be fixed in later revisions.

If there is enough of a demand from the community I will do something to move over the I2c, but you will loose analog on those ports, unless I jumper or something along those lines.

Yea it's a problem that defies a 'perfect' solution for all users in all cases. Bob's board uses jumper clips and that seems a pretty good compromise solution to me.
Lefty  



Which bootloader are you going to use?

I'm using the latest optiboot, when available I will try to include firmwares for all other known 1284 boards to make it an easy to install one-stop=shop package for all. I've tested firmwares for 8MHz (internal clock), 16MHz & 20MHz external crystals.

Don't forget to tell your future customers that the board would accept a 644P as a direct pin compatible replacement in the board, just software configuration changes, bootloader, etc.
Lefty




I do want to point out that you mentioned "My Customers", the goal was not to sale this board, but to make it open source and available for all. If you wan't one from me that's great I'll build you one.

Your input is valuable, I appreciate it and it will be taken under consideration for future revisions.

jbaum81


Here is the board Lefty is talking about.
This one was assembled by one of the users. I was thinking male jumpers at the top left for the A4/A5-SDA/SCL selection, he chose a female header.
This board also allows users to select off-board USB/Serial connectivity (such as FTDI Basic, or a CP2102 module), or onboard with a MIKROE483 (the least expensive FTDI module around) if the end usage needs full time USB access.

This other smaller SMD board is a simpler version, with an off-board FTDI type header, and no onboard regulator, good for battery powered applications (I use a 3 AA battery pack when testing) or some external power source.

Both use maniacbug's 1284 cores and Bobuino as board type.
More details on both here
http://www.crossroadsfencing.com/BobuinoRev17/

I have bare boards for both available, $6 for the larger board and $3 for the smaller, includes postage to US locations. International a bit more. PM me.


You didn't link the board, but I think I know which one your referring to.

I am also familiar with your boards and will be including firmware compatible to your layout. I understand one of the complaints with your boards was the lack of a centralized easy download, but I also understand that you have provided excellent support for your customers. The goal here is to simply make the 1284 easier to adopt as an arduino compatible board. Once available your more than welcome to refer your customers to my repository for downloads for your board(s).

retrolefty

Quote
Once available your more than welcome to refer your customers to my repository for downloads for your board(s).


That is of course the main disadvantage of using non stock arduino IDE supported AVR chip/board types. And while the IDE does allow for 3rd party expansion via a user hardware folder with core file changes and additions to support different chip types, that work never seems complete in that often when the arduino folks release a new IDE version there is sometimes new side effects or incompatibly problems to those prior installed user hardware supported chips/boards.
They can usually be fixed easy enough once the root cause is figured out, it does represents a continuous effort needed to keep the repository fresh.

Lefty

jbaum81

#13
Apr 02, 2013, 06:30 pm Last Edit: Apr 02, 2013, 06:36 pm by jbaum81 Reason: 1

Quote
Once available your more than welcome to refer your customers to my repository for downloads for your board(s).


That is of course the main disadvantage of using non stock arduino IDE supported AVR chip/board types. And while the IDE does allow for 3rd party expansion via a user hardware folder with core file changes and additions to support different chip types, that work never seems complete in that often when the arduino folks release a new IDE version there is sometimes new side effects or incompatibly problems to those prior installed user hardware supported chips/boards.
They can usually be fixed easy enough once the root cause is figured out, it does represents a continuous effort needed to keep the repository fresh.

Lefty


Yup, perhaps along the way I might pickup some help to keep up on the repository ;).

Not saying this is the end all be all solution, Although I'd like it to be lol, It's just my contribution to the community. If one person uses the downloads for firmware, or references my schematics, or buys or builds one of my boards then I've made a contribution. Although of course like anyone else I'd like it to gain momentum and be among the sanguino and babuino and the like, I'd like for people who need a little more (ALOT MORE) sram and flash to say hey I'll just get a Mega Junior, 1284 for this project.

CrossRoads

"I understand one of the complaints with your boards was the lack of a centralized easy download"
I'd not heard that.  I regularly refer folks to maniacbug's Mighty 1284 link for downloads.
https://github.com/maniacbug/mighty-1284p
Github is pretty centralized, isn't it?  I guess I could mirror/duplicate all that on my website if that would make life easier.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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