yup
mhennessy's got some good stuff. i've been watching his progress for a while now, a lot of good info on his site. of course we are not using the PGA2310, or any IC for that matter, in Son of Dork most likely. 😛 but the basic design goals are very similar. in fact, i am planning a more basic preamp for a friend, called Bastard of Dork, that may use the PGA2310.
mhennessy's got some good stuff. i've been watching his progress for a while now, a lot of good info on his site. of course we are not using the PGA2310, or any IC for that matter, in Son of Dork most likely. 😛 but the basic design goals are very similar. in fact, i am planning a more basic preamp for a friend, called Bastard of Dork, that may use the PGA2310.
I have used the dallas semi battery backed SRAM to store calibration data for measurement instruments. I found that they were quite reliable over long periods of time. As I recall, they were not user changeable batteries and the whole package was quite large.
The AVRs and PICs are fully static and both have low power modes that maintain the internal memory and registers while consuming < 10uA. I believe the AVR w/o a WDT only consumes 2-3 uA in low power mode.
Of course if the power goes out or you unplug it, you would lose the settings. To get around that you can use a uP supervisory circuit (< 1uA) in conjunction with a pair of diodes and an FET which acts as the switch to bring a tiny battery into the circuit. Just off the top of my head, i estimated that a pair of AAs (for 3V operation) would yield in excess of 40,000 hours of "no power" time for a 10uA load. You could easily get by with smaller batteries.
- ayman
The AVRs and PICs are fully static and both have low power modes that maintain the internal memory and registers while consuming < 10uA. I believe the AVR w/o a WDT only consumes 2-3 uA in low power mode.
Of course if the power goes out or you unplug it, you would lose the settings. To get around that you can use a uP supervisory circuit (< 1uA) in conjunction with a pair of diodes and an FET which acts as the switch to bring a tiny battery into the circuit. Just off the top of my head, i estimated that a pair of AAs (for 3V operation) would yield in excess of 40,000 hours of "no power" time for a 10uA load. You could easily get by with smaller batteries.
- ayman
1. Why you want to use so powerfull ATMEGA? Can't do this job simpler (and cheaper) 8051 for example?
2. All savings in non volatile memory (EEPROM) must be done only _after_ making changes. It's not necessary to save information on every second if all settings were not changed.
2. All savings in non volatile memory (EEPROM) must be done only _after_ making changes. It's not necessary to save information on every second if all settings were not changed.
8051 was what i originally spec'ed for the project and it is what i am prototyping with. i will move up to an ATMega only if i run out of memory on the 8051 (doubtful but you never know, i will have a full menu system for the user interface).
i may end up storing parameters in EEPROM, i'm not sure yet. it depends on whether they will all fit, i am looking to store a lot of customizations (e.g. text labels and settings memories for each input)
i may end up storing parameters in EEPROM, i'm not sure yet. it depends on whether they will all fit, i am looking to store a lot of customizations (e.g. text labels and settings memories for each input)
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