Status

ATmega328p Controller /w pluggable connectors for 6DIO, ICP, 2ADC
rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Status

Postby rpu_bus » Sun Sep 18, 2016 11:40 pm

DIN rail mountable ATmega328p with pluggable connections for ICP1, six digital I/O (3,4,10..13), and two analog inputs (ADC0, ADC1) with current sources for loop sensors.

Image

New ^7: Generic power input that accepts 7..36 VDC, the solar charge controller is removed.

Github page https://github.com/epccs/RPUno/
Last edited by rpu_bus on Thu Oct 05, 2017 2:48 pm, edited 4 times in total.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Thu Oct 20, 2016 5:02 pm

Changes for ^5 include adding a 5V pluggable connection next to the battery temperature compensation sensor input. Also, I have added some options for control of power to the shields VIN pin. By default, the VIN pin will now have power when the mega328p is held in reset. The IO2 line was floating in ^4 during a reset which caused the shield VIN to do random things. Finally, the LT3652 charge controller has a temperature shutdown sensor that may need to be off the board when power levels are high (e.g. 20W PV), so a header has been added to allow the sensor to be thermally decoupled from the board.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Fri Nov 11, 2016 12:02 am

^5 Assembly and Testing went well, though a bridge occurred near the LT3652 timer pin. Solder bridges should reduce with the use of a stencil, rather than dispensing from a syringe. I ran the load in voltage mode at 12.8V with the PV simulation supply set for 20V@1.5A and with the shutdown thermistor (the green and white twisted wires from under board) not mounted on the board it looks like charging the battery at up to 1.3A can be maintained without issues. This is good news for the RPUpi board.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Fri Mar 24, 2017 5:21 pm

^6 is on Tindie

https://www.tindie.com/products/ron-sutherland/rpuno/

If anyone wants to try this board? I was never planning to sell it but then I added the pluggable connectors and the flow/pulse sensor input and it started to look more useful. The thing with the ATmega328p is that Arduino has so many examples and almost everything works. The more microcontrollers that I try the more respect I gain for the ones that work. It also does 5V and 20mA per pin, and sometimes that is helpful.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Mon Sep 25, 2017 10:24 pm

^6 Tindie stock set to zero. I have added the ^6 eagle files to github if someone wants to look at them.

https://github.com/epccs/RPUno/tree/master/Hardware/Design

^7 board is in the works. The update removes the LT3652. The power will now be DC in the range 7 to 36V. The LT3652 works well enough but with a 12V battery, there is not much reason to use it. My experiments indicate that an LA battery will take a trickle charge of at least 0.02C without needing a charge controller. For example, my 3W PV (SLP003-12U) panel is charging a 10AHr AGM battery without damage. I looked for every excuse to keep the LT3652 but it is just not doing anything useful in my setup so it needs to go away.

A lot of the firmware will need to change for this update, but I will do it a little at a time.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Fri Nov 03, 2017 10:55 pm

^8 board is in the works.

The update allows DIO5, DIO6, and DIO7 to control the various current sources. DIO9 was doing this for some, but now they can all be enabled and disabled. DIO9 controls the 10mA ICP1 current source that is used with open collector sensors. DIO7 groups the digital and ICP1 current sources. DIO5 and DIO6 control the current sources that may be used with sensor loops measured by ADC0 and ADC1.

The Jumper that connected the 10mA source to the ICP1 Pulse Loop 100 Ohm resistor has been removed because DIO9 allows software control.

Note ^7 worked fine, but this seems like a better use for those digital lines that were once used with the charge control chip.

rpu_bus
Posts: 188
Joined: Sun Sep 18, 2016 6:07 pm

Re: Status

Postby rpu_bus » Thu Dec 14, 2017 11:50 pm

^9 board is in the works

Switch to ATmega328pb (add digital 20..23 on ADC6,ADC7,SDA1,SCL1)
Make ADC2 and ADC3 pluggable and Digital with level shift.
Use new IO22 and IO23 for CS2_EN and CS3_EN.
Make ADC0 and ADC1 Digital with level shift
Remove SPI pins from pluggable
Remove 10mA (and IO9 enable) pull up from ICP1 PL
Remove GND from ICP1
Use IO9 with a high side PMOS switch to allow disconnect from a PV string.

Again ^8 is working, but the tool chain to do a ATmega328pb is finally showing up (e.g. it is in Ubuntu 17.10 so far).


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