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[on:]

I'd like to know if there are substitutes in place of the ATmega.
After the prototyping phase, why we can't use only-one-time programmable microcontroller without eeprom instead of ATmega? I think it would be cheaper... isn't?

I'm a newbie, I'd be grateful to receive any advice!

[Reply #1 on:]

Not so sure about it being cheaper...

The AVR does have lock bits to prevent people from retrieving the firmware from the chip. But, if the volume justifies it ATMEL can probably make a chip with the program burned in.

[Reply #2 on:]

Thank for the answer, but I'm not worried about the ability to read the firmware. I don't work for NSA, I don't have anything that can be stolen 

I wonder if, after the end of a project, I could reclaim the ATmega and use instead a cheaper chip without EEPROM.
E2PROM memory are more expensive than PROM, or it should be so. It is also a market problem.
I dunno if there are microcontrollers OTP whiches can be used without writing new code. I'm just asking...

Obviously, it means not to write EEPROM during the use.

[Reply #3 on:]

The ATMega chip itself isn't that expensive, at least compared to an Arduino. There are plenty of examples of standalone boards being made that use the ATMega328 chip, programmed on an Arduino, then removed for use on the custom board. All that is needed to go with the chip is a crystal and a couple of caps.

[Reply #4 on:]

I'm sorry, but I don't understand. If I remove the ATMega328, I have to use another chip. What chip? Another ATmega or an ATtiny? Another waste of EEPROM... 

Please, can you explain what you mean? It is possible to use a no-EEPROM-based chip or not?

[Reply #5 on:]

Let's step back and verify that we know what we are talking about:

- The Arduino has flash program memory and data EEPROM.

So, are you referring to the program memory being an PROM instead of flash memory? Or are you referring the data EEPROM?

Either way, and I don't know much about chip making, we don't quite now if the facilities where the AVRs are made have the hability to cheaply use PROM instead of Flash or EEPROM. Also, how would you store data in PROM? Would it be made in the factory? Or would you burn the program? Because that would also have it's costs.

So in the end, what I think you're missing, is the fact that because a component is cheaper to make, doesn't mean that it is actually cheaper to incorporate it in a complete system. Plus, why have PROM instead of flash that allows you to upgrade firmware?

[Reply #6 on:]

I'm sorry, but I don't understand. If I remove the ATMega328, I have to use another chip. What chip? Another ATmega or an ATtiny? Another waste of EEPROM... 

Please, can you explain what you mean? It is possible to use a no-EEPROM-based chip or not?

From a manufacturing angle, you are talking pennies; but I agree with an earlier poster - if you wanted to do volume, I'm sure Atmel wouldn't argue (and create a custom chip for you).

BTW - have you looked and seen if Atmel offers a one-time programmable ATMega or ATTiny? They might (never looked myself)...

Once you go with an ATTiny, though - you're really pushing things as far as "waste" is concerned; this isn't something you should really care about, whether you're a hobbyist or a manufacturer (and if you really, really care about those pennies as a manufacturer - say, perhaps, you have Walmart pushing you to lower prices - then the Atmel line is not for you - go with PICs, they are much cheaper).

Finally - if you are a hobbyist, and are concerned about those pennies (or few dollars) that a new chip would cost - you are in the wrong hobby, and should reprioritize where your money is going.

[Reply #7 on:]

as far as I know, there are no OTP versions of any AVR processors.

FLASH-style memory has been cheaper than OTP-style memory for a long time now.  An OTP memory cell is essentially a UV-erasable ("EPROM") cell that doesn't let you expose it to UV for erasure.  The UVEPROM  The cheaper memory technology that you're thinking of is probably "mask programmed ROM" chips, where the code is actually implemented as a layer of the chip creation.  This is used for some very large volume applications, but it much more complex in the manufacturing phase (you have to get a MASK and have it used during the chip manufacturing.  Tens of thousands of dollars or more of NRE costs, assuming that the semiconductor manufacturer is willing to do it at all.

Atmel does have some OTP 8051-architecture chips based on flash technology.  I believe that they're essentially normal flash-based chips with the "erase" function disabled somehow.  While they're somewhat cheaper, I think the main idea is permanence-related, and they're only cheaper for marketing reasons.

[Reply #8 on:]

Lets look at it another way.

1) Flash was a godsend... and everyone in the microcontroller business was made happier.
2) Why should Atmel produce 2 chips that do almost the same thing where 1 is good enough.

Flash is used as non-volatile program storage... something you would need regardless and  you should not need to care about the specifics.  Flash was the reason Microchip PIC IC's went from $12.00 (16C54 UV Ceramic Package, or OTP Plastic Package) to $3.00 when the PIC16F84 Flash series was introduced.