Hey guys. i am working on Arduino MEGA (atmel 2560) board, i am reading its ports data and stroing into array by writing code Byte data[7000], i did it working with 7000 array size because arduino mega having a 8K RAM. but now i want to store data more than 7K , its about 15K. now i am looking for an alternative.
kindly suggest me an alternative without loosing acquisition/reading port time into any memory or external device.
Thank you
EJ
EJLED:
kindly suggest me an alternative without loosing acquisition/reading port time into any memory or external device.
How fast do you need to sample data and how much data (in bytes per sample) as this will determine alternate devices to use.
hey riva, i am acquiring 7K samples in 2 microseconds .
data[0]=PINA;
data[1]=PINB;
.
.
.
data[6999]=PINB;
u can consider that it using single clock to read port.
Arduino MEGA2560 can use external RAM. Read this: 512Kb SRAM expansion for the Arduino Mega (design) | Andys Workshop. They also offer ready to use shield.
Might also be worth considering an alternate MCU like the Teensy3.2 or an LeafLab Maple Min Clone. A lot of the pins are 5V tolerant and ports are 16 bits wide so might be able to read 16 pins in 1 instruction.
They have 64K SRAM so plenty of spare memory.
EJLED:
hey riva, i am acquiring 7K samples in 2 microseconds .data[0]=PINA;
data[1]=PINB;
.
.
.
data[6999]=PINB;u can consider that it using single clock to read port.
you might consider this product from Rugged Circuits their QuadRam It add 512Kbytes using the external Memory interface of the 2560.
Chuck.
P.S. I think your 2us for 7k samples is a bit imaginary. I can believe 2us for each sample, for 7k maybe 14ms.
Simple jump to Atmega1284P board, 16K bytes (16384).
I have used an array of 45 bytes x 350 rows of data, 15750 bytes, to blast data out to shift registers quick.
I used SPI at 8 MHz clock to send data out at 17 clocks/byte, just over 1uS each (47.8uS/row, verified with o'scope and logic analyzer).
Thanks crossroad,
I need 32 digital i/o i seen atmega1284p datasheet, it has only 4 ports. i also need interuupts and 2-3 control lines to trigger relay and other electronic.
is there any microcontroller having 5 ports with 16 kbytes. if it comes in DIP package it woulde be verymuch easy to work with it, rather handling LQFP etc..
Thanks a lot.
You can likely add a shift register or two for 8 or 16 or more inputs or outputs, read-in and output with SPI.transfer for fast updates. For example, I have a '328P with 12 shift registers here for 96 high voltage/high current outputs, rated for 50V, 150mA each:
http://www.crossroadsfencing.com/BobuinoRev17/
Sure, could make up a board like this one I have for the '2561 (also a 64-pin TQFP), add a USB connector - and then talk someone into coming up with the Core files for it so it could work in the IDE environment.
Thank you,
can u tell me from where i can get its gerber file for pcb making or its Expander board. means LQFP to DIP expander board.
The ATxmega256A3BU is a 3.3V device as well, so maybe a fullup board with 3.3V/5V buffering for the ports would make it more attractive vs the 3.3V boards that are out there now.
Have you reviewed the 2561 pinouts vs the ATxmega256A3BU? My board is designed to run the 2561 as a system on a chip kind of design, you can't just plop another processer on without reviewing the pinouts to make sure VCC & Gnd pins aren't shorted or something. The 2561 doesn't support direct USB interface like 256A3BU does, so a design change would be needed for that as USB connector to chip routing is critical in a design.
www.proto-advantage.com and http://schmartboard.com/ offer TQFP breakout boards if you want to try that.
Proto-advantage will order the part from digikey and install it on a breakout board for you.
ATXMEGA256A3BU-AU Microchip Technology | Integrated Circuits (ICs) | DigiKey
Digikey also offers an eval board
http://www.digikey.com/product-search/en/programmers-development-systems/evaluation-boards-embedded-mcu-dsp/2621773?k=ATxmega256A3BU
Thank you, but crossroads. 2561 is having only 8K SRAM, and it is almost same as 2560 MEGA arduino board. i need at least 5 PORTS + 16K. thats why i am planning for AT XMEGA 256A3BU.
Look at page 5 of the datasheet
http://www.atmel.com/Images/Atmel-8362-8-and-16bit-AVR-microcontroller-ATxmega256A3BU_datasheet.pdf
It has 6 ports.
A has 8 pins
B has 8 pins
C has 8 pins
D has 8 pins
E has just 6 pins
F has just 7 pins
Did you need 8 pins on 5 ports?
Ok, I was envisioning something like this, playing with layout still, but a complete system on a small board.
Will need bootloading somehow, PDI interface is not standard "Arduino as ISP" interface.
Once bootloaded, then download via serial.
So, similar to the 2561 in 64-pin TQFP.
But, different with the micro USB interface.
