Uno + CC3000 + RePaper + SRAM = WIN!

[pocketmoon]

Just wanted to say...

I'm having SO MUCH FUN with an Arduino Uno + Adafruit CC3000 breakout board + Embedded Artists 2.7" Repaper Display!

Threw in a 23LC1024 (1Mbit SPI friendly SRAM chip ) to act as a display buffer and a 74HC573N (latch I had handy to sort out the naught CC3000 holding on to MISO when it shoudn't).

Now have an e-ink display updating every 5 minutes display tweets!

Perhaps some SRAM breakouts would make cool Adafruit products?

Rob J
UK

[adafruit_support_mike]

Interesting suggestion. I'll pass it along to the hardware team.

[adafruit]

We have some FRAM in the works, both SPI and I2C, which is pretty cool cuz its as fast as SRAM but lasts thru power cycles like EEPROM/FLASH! probably get them in the shop in a couple weeks

[pocketmoon]

Excellent! I just love it when you folks get these cool non-DIP chips and make them available to us mortal breadboard hackers

[ishback]

Threw in a 23LC1024 (1Mbit SPI friendly SRAM chip ) to act as a display buffer and a 74HC573N (latch I had handy to sort out the naught CC3000 holding on to MISO when it shoudn't).

Hi pocketmoon, working on a project in which I need to dynamically update the screen (actually just a portion of the screen, but I think it's the same in terms of RAM requirements). Is there a schematic or diagram you could share to understand how to connect the components you mention above?

Thanks

[pocketmoon]

Hi,

I'm in the process of transfering the project from breadboard to proto-board so have a layout in Fritzing I can share. I'll upload it later when I'm home. SPI RAM is very easy to add and get working - the 23LC1024 is perfect because it has a wide voltage range (works with 3.3 or 5v devices). I

If you're only doing partial updates then this code works on an UNO with no extra SRAM needed:

https://github.com/BANNED/gratis

It's a modification to the epaper libraries. It's an interesting workaround, splitting the screen into chunks where a chunk is as big as your memory will allow and then repeat the draw loop N-times (once for each chunk). It's inefficient but because updating the epaper display is slow anyway it's not a big deal.

Cheers,

Rob

[pocketmoon]

First stab. I've yet to double check so caveat emptor!

cc1.jpg (842.86 KiB) Viewed 1250 times

[shmorgan]

I was just wondering, I don't see an oscillator on your diagram, are you using internal clocking on the AVR?

[pocketmoon]

I was just wondering, I don't see an oscillator on your diagram, are you using internal clocking on the AVR?

Yep, I followed the 'low power arduino' example here : http://www.gammon.com.au/forum/?id=11637

I followed the guide to stick the Lilypad bootloader in there using the latest Arduino IDE and a USBTinyISP. All setup nicely to run at 8mhz internal clock.

The plan is to run the whole lot of a single 18650 type li-ion battery 3.7v 3100mAh

In my test setup (Arduino UNO), when in deep sleep the things drawing most current are the LEDs!

[agilbertson_marqeta]

Just wanted to say...

I'm having SO MUCH FUN with an Arduino Uno + Adafruit CC3000 breakout board + Embedded Artists 2.7" Repaper Display!

Threw in a 23LC1024 (1Mbit SPI friendly SRAM chip ) to act as a display buffer and a 74HC573N (latch I had handy to sort out the naught CC3000 holding on to MISO when it shoudn't).

Now have an e-ink display updating every 5 minutes display tweets!

Perhaps some SRAM breakouts would make cool Adafruit products?

Rob J
UK

Hi pocketmoon (and everyone else reading this)! The e-ink display is quite the miracle of modern technology, isn't it?

I'm trying to use the e-ink display (the little 1.44 inch version) connected to an Arduino Micro *without* having to have an external memory chip hooked up to it. I've got a "screenbuffer" created in memory, but when calling EPD.image(&screenbuffer[0]), I end up with garbage on the screen - both with the original RePaper library and your reworked version. I've written some test code to validate that what I think is there really is there, and even output it in a format that I can dump into a text file that I save with a .xbm extension and open in an image viewer. Everything there is not quite correct but close enough that I shouldn't be getting garbage on my screen. Any ideas on what else I need to do to get this working? Let me know if you want any additional details....I can post a link to the full sketch if that's what it takes.

Thanks,
Andy

[adafruit_support_mike]

Your buffer will consume most of the available SRAM. The 1.44" RePaper display has a 128x96 array of pixels, and assuming one bit per pixel you're looking at 1536 bytes. That only leaves 512 bytes for all the remaining objects and variables in your program.

[pocketmoon]

Hi Andy,

A smart dude did this :

https://github.com/BANNED/gratis

Bit of a hack but uses a fraction of ram for display. It uses ,multiple passes to update the whole display so slower but that's not a big issue with these displays.

[agilbertson_marqeta]

I know that a very smart dude did that. I'm the dummy here, and I need help. I replaced my existing EPD library with that one. Now I get this on my e-ink display:
https://lh5.googleusercontent.com/-sLce ... 162328.jpg
(Sorry for the giant image, Picasa used to let you link to resized pictures but Google Photos apparently doesn't, so I just put a link instead of the image itself.)

when I am expecting this:



(like I said..."not quite correct" but hopefully you can figure out what I was intending before the headache gets too bad).

Any ideas what's going on?

adafruit_support_mike: I already ran into an issue with that; I'm working around it (as much as possible) by declaring everything I can as PROGMEM const. Turns out you can upload sketchs to the Micro in such a way that unplugging/replugging the Micro into a Linux Mint machine's USB port results in a kernel panic. Fun!