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Very low ram applications

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I have seen some pic controllers such as dspic30f4011 with very less flash and ram. For example ram is around 2kb. Why generally ram is very less? Is it expensive? What are the main applications of these kind of devices? Since other features are extensive. With this less memory what people are going to do? Just i wanted to know.
 

Ian Rogers

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I use a small pic12 to serve as a quadrature encoder, needs very little memory.... I have also turned these into 555 timers again requiring very little memory...

There are many applications where memory isn't important..
 

NorthGuy

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Less money, less space, improved power consumption.

There's no premium for having unused RAM in your chip.
 

JimB

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As an example, this signal source which I made, uses a PIC 16F887.

DDS SigGen.jpg

The PIC does the following:
Reads the pushbuttons.
Reads the quadrature encoder.
Writes to the LCD display.
Writes 40bits of configuration and tuning data to an AD9851 DDS chip.

The progam occupies less than 1.5k of memory.

JimB
 

JimB

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Crikey that AD9851 chip is an arm and a leg ... !
??
A little ready built module from the mystic orient was less than £10.
I don't know if they are the real deal or "counterfeit" chips, but I have had two 9850s and a 9851 and all did exactly what it said on the tin.
Err I mean datasheet.

But to buy the real thing, just the bare chip from RS Components, yes limbs would have to be sacrificed.

Thank you both for the compliment.
However, it could be better. Inside was built simply to work as a high level signal source (1 volt or so). RF niceties like rigorous screening were ignored while concentrating the efforts on getting the programming right.
One day I may get around to rebuilding the analogue side of the thing.

JimB
 

Nigel Goodwin

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??
A little ready built module from the mystic orient was less than £10.
I don't know if they are the real deal or "counterfeit" chips, but I have had two 9850s and a 9851 and all did exactly what it said on the tin.
I must admit, I've been considering ordering some to play with :D

However, I'm not sure I've really got any use for an RF generator these days?

Thank you both for the compliment.
However, it could be better. Inside was built simply to work as a high level signal source (1 volt or so). RF niceties like rigorous screening were ignored while concentrating the efforts on getting the programming right.
One day I may get around to rebuilding the analogue side of the thing.
Still looks nice, and the only difference between 1V and 10mV is an attenuator :p
 

JimB

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Still looks nice, and the only difference between 1V and 10mV is an attenuator :p
Quite correct.
But, if the 1v source is not correctly screened so that the only place for RF to come out is via the connector to the (correctly screened) attenuator, then you have not got a 10mV source, it could be anything between 10mV and the 1V you started with.

Not only that, but 10mV is a rather big signal when playing with radios.
A signal less than 1uV is often called for, so the screening and the attenuator has to be good.

JimB
 
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