Hi All, i am looking for a new Micro for a private project: Needed Features: - Performance of a 12MHz 80C535 is enough - 2 serial Ports - 128kB Flash - Battery bufferd SRAM on board (16k and more) - RTC - 4 8 or 16bit Timers - GPIO's for Key's (8), LCD (Standart 4 bit and control) and LED (8) - SD card interface Most cruical is that a free compiler is available since I dont want to pay another system. The source is mainly written HW independent but I have no OS. I would lie to use one but development time in spare time is limited so I rather would program it plain again. I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. An suggestions? Thanks a lot! Andreas
Q:Help with Microcontroller selction
Started by ●January 18, 2008
Reply by ●January 18, 20082008-01-18
On Jan 18, 10:20=A0pm, Andreas Schweiger <andreas.schwei...@gmx.de> wrote:> Hi All, > > i am looking for a new Micro for a private project: > > Needed Features: > > - Performance of a 12MHz 80C535 is enough > - 2 serial Ports > - 128kB Flash > - Battery bufferd SRAM on board (16k and more) > - RTC > - 4 8 or 16bit Timers > - GPIO's for Key's (8), LCD (Standart 4 bit and control) and LED (8) > - SD card interface > > Most cruical is that a free compiler is available since I dont want to > pay another system. > The source is mainly written HW independent but I have no OS. > I would lie to use one but development time in spare time is limited so > I rather would program it plain again. > > I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. > > An suggestions? >I think, you can dig into the pile of PIC microcontrollers to see if any of those matches your specification. Karthik Balaguru
Reply by ●January 18, 20082008-01-18
On Jan 18, 9:20 am, Andreas Schweiger <andreas.schwei...@gmx.de> wrote:> Hi All, > > i am looking for a new Micro for a private project: > > Needed Features: > > - Performance of a 12MHz 80C535 is enough > - 2 serial Ports > - 128kB Flash > - Battery bufferd SRAM on board (16k and more)Easier if you can settle for 8K> - RTC > - 4 8 or 16bit Timers > - GPIO's for Key's (8), LCD (Standart 4 bit and control) and LED (8) > - SD card interface > > Most cruical is that a free compiler is available since I dont want to > pay another system. > The source is mainly written HW independent but I have no OS. > I would lie to use one but development time in spare time is limited so > I rather would program it plain again. > > I looked at ATMELS ATmega128 but no bufferd SRAM and RTC.Sure there is, at least for some AVRs. You can run it in power saving mode with the RTC clock running. You should copy critical SRAM data into EEPROM anyway. Battery SRAMs are for lazy designers.> > An suggestions? > > Thanks a lot! > > Andreas
Reply by ●January 19, 20082008-01-19
Hi,> > I think, you can dig into the pile of PIC microcontrollers to see if > any of those matches your specification. >thank you, will have a look. Andreas
Reply by ●January 19, 20082008-01-19
Hi,>> - Battery bufferd SRAM on board (16k and more) > > Easier if you can settle for 8KThe application will have to store data which can get more and more in time (musical allpiance). So 8k is the adsolut minimum.>> I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. > > Sure there is, at least for some AVRs. You can run it in power saving > mode with the RTC clock running. You should copy critical SRAM data > into EEPROM anyway. Battery SRAMs are for lazy designers. >Well, I need the SRAM for storing application data and that data can grow by input of the user. Storage (SD or other cards) I dont have so I need to hold the data in battery buffered SRAM since I have a power supply which can (of course) be switched off. Thats why I use byttery back up. Thanks, Andreas
Reply by ●January 19, 20082008-01-19
On Jan 19, 6:07 am, Andreas Schweiger <andreas.schwei...@arcor.de> wrote:> Hi,>> - Battery bufferd SRAM on board (16k and more) > > > Easier if you can settle for 8KThere are some high end AVR that will work for you, with 8K SRAM and 2K EEPROM.> > The application will have to store data which can get more and more in > time (musical allpiance). > So 8k is the adsolut minimum. > > >> I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. > > > Sure there is, at least for some AVRs. You can run it in power saving > > mode with the RTC clock running. You should copy critical SRAM data > > into EEPROM anyway. Battery SRAMs are for lazy designers. > > Well, I need the SRAM for storing application data and that data can > grow by input of the user. > Storage (SD or other cards) I dont have so I need to hold the data in > battery buffered SRAM since I have a power supply which can (of course) > be switched off. > Thats why I use byttery back up.Unless you have a big battery, SRAM will kill it quickly. EEPROM can store data indefinitely. Any uC running SRAM will need a few mA at least. AVR, for example, can wait for RTC interrupt with less than 100uA, if you design it right. External EEPROM or FLASH is available as well.> > Thanks, > > Andreas
Reply by ●January 19, 20082008-01-19
Andreas Schweiger wrote:> Hi All, > > i am looking for a new Micro for a private project: > > Needed Features: > > - Performance of a 12MHz 80C535 is enough > - 2 serial Ports > - 128kB Flash > - Battery bufferd SRAM on board (16k and more) > - RTC > - 4 8 or 16bit Timers > - GPIO's for Key's (8), LCD (Standart 4 bit and control) and LED (8) > - SD card interface > > Most cruical is that a free compiler is available since I dont want to > pay another system. > The source is mainly written HW independent but I have no OS. > I would lie to use one but development time in spare time is limited so > I rather would program it plain again. > > I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. > > An suggestions? > > Thanks a lot! > > AndreasThat is a lot of RAM in a 8 bit, and battery backed is even rarer, so you have moved into a supply desert. Better might be to look at external DataFLASH, or Ramtron FRAM or one of their processor companions : RTC + FRAM in one package. That gives you a scalable storage solution, fast and low power (FRAM does not even need a battery), and leaves the Core selection much simpler.
Reply by ●January 19, 20082008-01-19
Hi! linnix wrote on 19/01/08 19:53 MET:> EEPROM can store data indefinitely.Beware of the fact that EEPROMs can not be erase indefinitely, there's a limit of how often each erase-block can be erased. An EEPROM with 100.000 erase cycles, the worth-case scenario of a full erase every second gives you a chip lifetime of 1.15 days. So it all depends on how much data you are storing and how often each erase-block is being reprogrammed. -- MfG / Regards Friedrich Lobenstock
Reply by ●January 19, 20082008-01-19
On Jan 19, 4:38 pm, Friedrich Lobenstock <fl@_REMOVETHIS_fl.priv.at> wrote:> Hi! > > linnix wrote on 19/01/08 19:53 MET: > > > EEPROM can store data indefinitely. > > Beware of the fact that EEPROMs can not be erase indefinitely, there's a > limit of how often each erase-block can be erased. > > An EEPROM with 100.000 erase cycles, the worth-case scenario of a full > erase every second gives you a chip lifetime of 1.15 days.I am not saying that you should stream data into EEPROM directly. Before going into power down or standy mode, copy critical data from SRAM to EEPROM.
Reply by ●January 19, 20082008-01-19
On Jan 19, 9:07=A0am, Andreas Schweiger <andreas.schwei...@arcor.de> wrote:> Hi,>> - Battery bufferd SRAM on board (16k and more) > > > Easier if you can settle for 8K > > The application will have to store data which can get more and more in > time (musical allpiance). > So 8k is the adsolut minimum. > > >> I looked at ATMELS ATmega128 but no bufferd SRAM and RTC. > > > Sure there is, at least for some AVRs. =A0You can run it in power saving=> > mode with the RTC clock running. =A0You should copy critical SRAM data > > into EEPROM anyway. =A0Battery SRAMs are for lazy designers. > > Well, I need the SRAM for storing application data and that data can > grow by input of the user. > Storage (SD or other cards) I dont have so I need to hold the data in > battery buffered SRAM since I have a power supply which can (of course) > be switched off. > Thats why I use byttery back up. > > Thanks, > > Andreasconsider the Ultra low Power External SRAM by AMI, for instance the 32K x 8 bit serial SRAM (about 50 cents) http://www.amis.com/pdf/ulp_memory/serial_srams/N256S08xxHDA_ds.pdf it only requires 200nA to retain memory so battery backup shouldn't be a problem the also have megabyte parallel devices http://www.amis.com/products/ulp_memory/ulp_srams/index.html