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Topic: [Solved] Problems accessing parallel SRAM (Read 9188 times) previous topic - next topic

leo72

I have a charger for a Motorola phone that has a power output of 5V-500mA: I cut its connector and made a built-by-me adaptor to use with breadboards :-)
It works very well: I've already used it in a replica of the Hackvision miniconsole.

CrossRoads

That sounds like plenty then. The other thing you might consider is 0.1uF caps between the VCC & GND pins of the chips.
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.

stimmer

Code: [Select]

    shiftIn(load_data, clock_pin, value);


is wrong. It doesn't store the value received anywhere. Strangely, I can't find shiftIn in the reference documentation, but the function definition is
Code: [Select]
uint8_t shiftIn(uint8_t dataPin, uint8_t clockPin, uint8_t bitOrder)

so I guess you want value= shiftIn(load_data, clock_pin, LSBFIRST);  (or MSBFIRST)

Debugging with an LED is a good idea. Start off by making sure the right addresses are getting to the RAM.
Due VGA library - http://arduino.cc/forum/index.php/topic,150517.0.html

leo72

@CrossRoads:
I've already put some 0.1 uF cap.s around, on every chip Vcc.

@stimmer:
Is was to find ShiftIn for me too.
If you go into the References/Language, you find "ShiftOut". From it, at the end of its page, you'll find the link to ShiftIn:
http://arduino.cc/en/Reference/ShiftIn

Nevermind, I saw that I made a mistake. In fact, your sintax is correct, 'cause "value" must be replaced from bitorder. Thanks, maybe this is the good time!  XD
I'll try as soon as possible...

leo72

SUPERB! It works!!!!  XD XD XD XD

3 days looking at the circuit thinking the worst things.... and it was s stupid function that I miswrote in my code!!!

Thnaks stimmer for having opened my blind eyes  ^_^
Thanks CrossRoads for your suggestions, too, because with your suggestions I made a very much simplier circuit with 4 or 5 pins less than the original.

leo72

I was thinking.... what about an article for the playground? If I'm right, there are no articles about reading/writing from parallel RAM, isn't it?

I think it could be interesting for someone else, don't you?

CrossRoads

Glad to help - hadn't looked into your syntax, didn't occur to me there might be something amiss. Nice catch there stimmer.

Playground article - sounds good. There was someone else earlier trying to come up with a dual access SRAM. Haven't heard anything on that one in a while.

Does this look familiar?
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.

leo72

Yes, it looks veery familiar because.... it was me that asked that XD XD
I had drawn my circuit using your old schematic too :-)

You are a force, my friend  XD XD
Thanks again for your support and for your patience.

This is the first step. Access to an SRAM with 1 Arduino. Now that I got the Master Degree in Chiponics ( :smiley-mr-green: ) I can start trying to access to the SRAM using an Arduino and a vanilla Atmega.


CrossRoads

Oh, that is too funny! I was looking in the old forum trying to find that thread. I don't think you had any code then.
Nice work - some of you guys are way better than me at putting that stuff in functions. My code tends to look like everything all written out.
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.

leo72

When I made that request I didn't have any code but I didn't have any idea on how chips works too  :smiley-mr-green:
I learnt about chips thanks to this forum and the datasheets of the chips I bought.

And, I'm sure, it's easy with theachers like you and stimmer  :D

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