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1  Development / Other Hardware Development / Re: 8MB Ramdisk for Arduino.. on: March 08, 2014, 11:46:40 am
would have liked to try it but no method of shipping to Canada ....
 
2  Using Arduino / Storage / Re: Is there a SRAM extension Shield? on: January 26, 2014, 09:04:07 am
willing to share the cpld code ?

a few months ago i started to build a large fifo out of  a AL440B but got distracted / will revisit eventually
3  Products / Arduino Due / Re: A/D sampling frequency on: December 02, 2013, 08:09:07 am
http://www.atmel.com/Images/doc11057.pdf
4  Products / Arduino Due / Re: A/D sampling frequency on: November 29, 2013, 01:42:02 pm
RTFM
      Search & Read the forums  - people have talked about this before 
      may people have posted code (myself included)

     my favourite way is use the PDC
     others favour  tight loops after modifying the analog read command
     others rewrite the analog read
     
 
5  Products / Arduino Due / Re: A/D sampling frequency on: November 28, 2013, 07:31:40 am
all the way up to 1M sample/sec
6  Products / Arduino Due / Re: using SRAM bus for UTFT ? on: November 10, 2013, 04:41:52 pm
I have not pushed it
  working with 6" ribbon cable & things tended to get messy at 100ns so i backed off
  ssd1963 claims to work at 50Mhz or faster (at least this one had a 50mz clock )
... but i doubt i get close with long wires  ..
7  Products / Arduino Due / Re: Analog-to-digital converter in Due on: November 09, 2013, 11:09:44 am
the adc dac are both fast enough
 take the print statement out the loop
8  Products / Arduino Due / Re: using SRAM bus for UTFT ? on: November 07, 2013, 10:31:22 am
this turned out to function quite well with single byte transfers on the order of 1/2 us
both reading & writing

it did take a bit of work to find the right parameters esp with this cheapo display
& trying to figure out some of the parameters of the ssd1963 .... 

but it works !!
9  Products / Arduino Due / using SRAM bus for UTFT ? on: November 03, 2013, 11:38:09 am
Has anyone tried this ? (i'm digging into the internals  as it type ..)
just using a single address line & an 8bit bus ?

the reason behind this - i bought a 7" TFT 6 mo. ago & tried to attach it for the first time yesterday
--&  find out that 3 of the assigned data lines are dead on my DUE  (ya likely killed them with 5v , sigh ... )
so rather than reassign the bits why not use  External Memory Bus/Static Memory Controller http://forum.arduino.cc//index.php?topic=152644.msg1145789#msg1145789
should be faster right ??
bit of hacking up henning karlsen code but ....


10  Using Arduino / Storage / Re: the memry card is write-protected on: October 22, 2013, 02:01:23 pm
last time that had happend to me the card had died
was a new card & got replaced but ...

power fail during a write will kill some cards
11  Using Arduino / General Electronics / Re: simple opamp circuit ? on: September 24, 2013, 04:46:42 pm
Here's a circuit that should work with any 5V rail-to-rail output op amp.
i'll give that one a try
 i had tried today with a similar circuit / but to find out that i have to wait for smd holders for the proper opamp   - 8dip ones i was trying with didn't have the bandwidth ...

 
12  Using Arduino / General Electronics / Re: simple opamp circuit ? on: September 24, 2013, 04:43:46 pm
Most (all?) "rail to rail" op-amps, aren't.  Close maybe, but still asymptotic.  Only way to get 100% of a voltage range is for the supplies to exceed it.
understood / but i don't want to lose 25% of my width (5-10% if i really have to ..)
 and at some point don't mind if 0V is hard to get to ...
13  Using Arduino / General Electronics / Re: simple opamp circuit ? on: September 23, 2013, 05:13:37 pm

.75-3 & doing in software doesn't cut it - you loose 1/4 the range ... no point in having 12 bits (4096 ) if you toss out 1/4 of them
 
plenty of rail to rail single supply opamps /
 
14  Using Arduino / General Electronics / simple opamp circuit ? on: September 23, 2013, 04:23:34 pm
i need this for a Due input so 0-3.3

my signal is ~1-4v so i need to subtract 1v from the input to get it in range
  it has to be fast (signal changes every 2us)  & not AC coupled ..

IF i had a negitive supply i could sum the inputs  ... but i don't have negitive supplys at hand (ment to be in a portable device )....

 does anyone have a solution ? 
15  Products / Arduino Due / Re: Configure Arduino Due as SPI slave on: September 19, 2013, 05:41:36 pm
you have to state the correct spi instance

as seen in
/hardware/arduino/sam/system/libsam/source/spi.c

Code:
{snip out lots of code}
extern void SPI_Configure( Spi* spi, uint32_t dwId, uint32_t dwConfiguration )
{
    pmc_enable_periph_clk( dwId ) ;
    spi->SPI_CR = SPI_CR_SPIDIS ;

    /* Execute a software reset of the SPI twice */
    spi->SPI_CR = SPI_CR_SWRST ;
    spi->SPI_CR = SPI_CR_SWRST ;
    spi->SPI_MR = dwConfiguration ;   ///<------------------------------------------------------------
}
{more code follows }
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