Post by thread:[PIC]: datalogger

> I wonder if it is possible to use a RAM from a pc > or at least a larger ram that can keep the data until > it is downloaded to a pc. > thanks for any help > Ernst You will have a lot of work to do to interface with the SIMMs, but the cache SRAMs (usually 32k x 8) are simple and fast (under 30ns). They're just like ordinary SRAMs, eg a 62256, except in a slimline package, ie 0.3" wide not 0.6", same pin-out, voltage and low current power-down state. Most newish motherboards will have anywhere from 1 to 9 of them, use as many as you need in parallel and just select the one you want with CE. Check the web for specs, some that I have with what I thought was a 32kB part code are in fact 64kB, a little bonus -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

I am verry happy that I have got this Ideas. I can now see that I of cource can skip the AD- chip. I am going to use only the ad's on the pic. But I must have more Ideas and preferably also some shematic how to connect a largest possible s-ram. Would it be an idea to use serial eproms? What sizes can we get serial eproms? Ernst Jinx wrote: {Quote hidden}> > I wonder if it is possible to use a RAM from a pc > > or at least a larger ram that can keep the data until > > it is downloaded to a pc. > > thanks for any help > > Ernst > > You will have a lot of work to do to interface with the SIMMs, but > the cache SRAMs (usually 32k x 8) are simple and fast (under > 30ns). They're just like ordinary SRAMs, eg a 62256, except in > a slimline package, ie 0.3" wide not 0.6", same pin-out, voltage > and low current power-down state. Most newish motherboards > will have anywhere from 1 to 9 of them, use as many as you need > in parallel and just select the one you want with CE. Check the > web for specs, some that I have with what I thought was a 32kB > part code are in fact 64kB, a little bonus > > -- > http://www.piclist.com hint: To leave the PICList > .....piclist-unsubscribe-requestKILLspam@spam@mitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:" PIC only "[EE]:" engineering "[OT]:" off topic "[AD]:" ad's

> I am verry happy that I have got this Ideas. I can now see that > I of cource can skip the AD- chip. I am going to use only the ad's > on the pic. But I must have more Ideas and preferably also some > shematic how to connect a largest possible s-ram. Would it be > an idea to use serial eproms? What sizes can we get serial eproms? How much data do you need to log? How fast? How many channels at what resolution? I just finished a project that was a one-off data logger for a customer's research project. It had these characteristics: 1 - Up to 4 groups of 8 analog input channels for a total of 32. They used 24 channels. Could be easily extended to many more groups of 8 channels. 2 - 10 bits recorded per channel per data point. 3 - Data point period selectable down to 2mS (500Hz) in multiples of 1mS. 4 - Selectable number of data points stored per sample. 5 - Up to 99 individual samples, or a maximum of about 26,000 data points. 6 - RS-232 connection with Windows software to download each sample to a separate data file. 7 - Selectable trigger position within sample. The unit contains non-volatile memory, and is meant to be battery operated for data collection in the field. For each sample, the unit is manually armed, meaning it is now waiting for a trigger event. The trigger can come from a special analog input (they used a microphone to detect a particular event), or a trigger can be caused deliberately by the user. There is also provision for taking a "static reading" sample that contains just one data point. Let me know if this is at all close to what you are trying to put together. Even if a few modifications are required, it would probably be cheaper to spin off another one of these things than to create your own from scratch. If you'd like to look into this further, please contact me privately at olinKILLspamcognivis.com or (978) 772-3129. ***************************************************************** Olin Lathrop, embedded systems consultant in Devens Massachusetts (978) 772-3129, .....olinKILLspam.....cognivis.com, http://www.cognivis.com -- http://www.piclist.com hint: PICList Posts must start with ONE topic: "[PIC]:" PIC only "[EE]:" engineering "[OT]:" off topic "[AD]:" ad's