Post by thread:512 KByte of memory

Hi everybody, I'm working on a data aquisition project with a PIC uC involved. Does anybody have an idea about if it's possible to attatch 512 KBytes of NV- Data Memory to any pic controller and if how then how ?? (this sounds stupid!) I would be realy glad if somebody has any idea (If 512 is difficult, then what about 256,128 or 64KBytes) Ciao Mikael

> > Hi everybody, > > I'm working on a data aquisition project with a PIC uC involved. > Does anybody have an idea about if it's possible to attatch > 512 KBytes of NV- Data Memory to any pic controller and if how > then how ?? (this sounds stupid!) > I would be realy glad if somebody has any idea (If 512 is difficult, > then what about 256,128 or 64KBytes) > > Ciao > Mikael > I think its not possible. The Basic Stamp can't write an address that high. You won't be able to store data in a location if you can't write the address. You can put a 256 byte EEPROM on each IO pin, and write to those, but that still doesn't give you the storage you want.

>I'm working on a data aquisition project with a PIC uC involved. >Does anybody have an idea about if it's possible to attatch >512 KBytes of NV- Data Memory to any pic controller and if how >then how ?? (this sounds stupid!) >I would be realy glad if somebody has any idea (If 512 is difficult, >then what about 256,128 or 64KBytes) Dallas semiconductor do some nifty DRAM nonvolatisers, which might be your answer - they take care of refreshing the RAM, cope with main system power failure (you do, of course, need to supply backup power to the RAM and the controller) and provide a serial interface (1-wire? 2-wire?) to the RAM which is ideal for use with a PIC. If I can find the databook I'll post the part numbers. Regards, Dave

Interfacing a PIC to 512 KBytes of memory (or more) is only a matter of trade-offs. How fast do you need to access this memory? If time is not critical you could attach a serial to parallel shift register to one I/O pin on the PIC and shift an address into it. You could then use another I/O pin as a strobe and 8 I/O pins for a data bus. I have used this approach for smaller amounts of external memory locations and registers by replacing the shift register with 8 I/O pins to address 256 locations. I don't see why this couldn't be expanded to the memory sizes you need. Mark A. Corio Rochester MicroSystems, Inc. 200 Buell Road, Suite 9 Rochester, NY 14624 Tel: (716) 328-5850 Fax: (716) 328-1144 e-mail: spam_OUTMcorioTakeThisOuTaol.com ***** Designing Electronics For Research & Industry *****

On 10/31/95 you wrote: >Does anybody have an idea about if it's possible to attatch >512 KBytes of NV- Data Memory to any pic controller and if how >then how ?? (this sounds stupid!) Dallas has a part (DS1280) in there 94-95 NV RAM data book. It converts a 3-wire serial interface to a JEDED standard bytewide interface for memory. It supports up to 512K. Mike

> > I'm working on a data aquisition project with a PIC uC involved. > > Does anybody have an idea about if it's possible to attatch > > 512 KBytes of NV- Data Memory to any pic controller and if how > > then how ?? (this sounds stupid!) > > I would be realy glad if somebody has any idea (If 512 is difficult, > > then what about 256,128 or 64KBytes) > > Ciao > > Mikael You could try daisy chaining two Cmos 4040 timers together controlled by two signals. One clock, for address selection and one for reset to zero address. Get an off the shelf 8 bit wide static ram that will have its data lines connected directly to 8 PIC lines. You then only need to control the read, write and chip select of the Ram. Battery backup can be provided by a simple diode/resistor network from any variety of sources such as Ni-Cad, lithium or a large capacitor. February 95 Circuit Cellar magazine gives examples of doing simple battery backups. Or you could use a Dallas Ram backup (smart socket) if cost isn't a big factor. The last time I purchased Static Rams, the 128K by 8 bit was the most cost effective, but that was perhaps 18 months ago. This may have changed. Perhaps you can get your 512K in one IC at a realistic price. Don... Low Cost DIY PCB's for PICs & COM1/LPT1 PC I/O Interface Kits ;! Don McKenzie. 29 Ellesmere Cres., Tullamarine. 3043 Australia ;@ Tel +61 3 9338 6286 Mobile +61 19 939 799 .....donmckKILLspam@spam@tbsa.com.au ;# Check My Promo Disk at http://rasi.lr.ttu.ee/~sis/mirror/don/ ;$ Type: 'finger donmckKILLspamtbsa.com.au|more' for more information.

---------- You can use a number of serial to parallel chips to create the memory address, and use standard ram's. But when you find that you need a specialized type of chip, why not program a PIC chip to do the job. --------- Bill Cornutt .....billcornKILLspam.....infoserv.com Located in Ione California USA. A small town in Northern California. Sitting against the foothills of the Mother Lode. ----------------------------------------------------

At 12:08 PM 31/10/95 +0100, you wrote: >Hi everybody, > >I'm working on a data aquisition project with a PIC uC involved. >Does anybody have an idea about if it's possible to attatch >512 KBytes of NV- Data Memory to any pic controller and if how >then how ?? (this sounds stupid!) >I would be realy glad if somebody has any idea (If 512 is difficult, >then what about 256,128 or 64KBytes) > > Ciao > Mikael Add one more suggestion to the several you have already received. Use 4 lines for address, 4 lines for data and one for strobe. The 4 address lines when decoded, should give you 16 lines. Attach lataches at 5 of the addresses. This gives you a 20 bit output port. Connect this to the 256K memeory. Use two more latches to read and two to write data. Another address to provide the write pulse. Data(4) ------------------------------------------------------- | +-------+ +--+---+ Address(4) -----|Decoder|--|Latch1| .... more Latches Strobe(1) -----| | +--+---+ | | | | | +-------------+ +-------|A0-3 256K | Latch2 --------|A4-7 RAM | Latch3 --------|A8-11 | Latch4 --------|A12-15 | Latch5 --------|A16-19 | | | Latch6 ---+----|D0-3 | Buff7 ---+ | | | | Latch8 ---+----|D4-7 | Buff9 ---+ | | | | From decoder --|WR | 10 To read Set address on Latches 1 to 5. Read buffer 7 for 1st nibble Read buffer 9 for 2nd nibble To write Set address on Latches 1 to 5 Set data on Latches 6 and 8 Send write pulse by putting out address 10 Regards Prashant +----------------+ ------------------------------------------------- | | Prashant Bhandary | +---+ | Spatial Information Systems Section | | | | Roads and Traffic Authority | | | | Rosebery NSW 2018, AUSTRALIA | | | | Tel: +61-2-662 5299 | | +----+ | Fax: +61-2-662 5348 | | | | Email: EraseMEprashbspam_OUTTakeThisOuTrta.oz.au | +--------+ | | Still a newbie | "2b|!2b" - William Shakespeare +----------------+ -------------------------------------------------

If you decide to use 64k bytes rather than 512k for your data-logger, we have built a similar device and due to pricing breaks we have a few spare unpopulated PCBs. The PCB measures about 25mm x 25mm x 1.5mm and is designed to take the surface mount 16LC84 and up to eight 24LC65 64kbit IIC eeproms. The whole thing is powered from a lithium cell. If you are interested we could come to some arrangement about selling on some PCBs. Ben Heller Department of Medical Physics, Royal Hallamshire Hospital, Sheffield

---------- Forwarded message ---------- Your message is being returned to you unprocessed because it seems to have been already sent to the PICLIST list. That is, a message with identical body (but possibly different headers) has been posted to the list recently, either by you or by someone else. OK, I'll add the above text! That should trick it hey? :-)) > > I'm working on a data aquisition project with a PIC uC involved. > > Does anybody have an idea about if it's possible to attatch > > 512 KBytes of NV- Data Memory to any pic controller and if how > > then how ?? (this sounds stupid!) > > I would be realy glad if somebody has any idea (If 512 is difficult, > > then what about 256,128 or 64KBytes) > > Ciao > > Mikael You could try daisy chaining two Cmos 4040 timers together controlled by two signals. One clock, for address selection and one for reset to zero address. By pulsing the clock, you increment the address, an old tried and true method! Get an off the shelf 8 bit wide static ram that will have its data lines connected directly to 8 PIC lines. You then only need to control the read, write and chip select of the Ram. Battery backup can be provided by a simple diode/resistor network from any variety of sources such as Ni-Cad, lithium or a large capacitor. February 95 Circuit Cellar magazine gives examples of doing simple battery backups. Or you could use a Dallas Ram backup (smart socket) if cost isn't a big factor. The last time I purchased Static Rams, the 128K by 8 bit was the most cost effective, but that was perhaps 18 months ago. This may have changed. Perhaps you can get your 512K in one IC at a realistic price. Don... Low Cost DIY PCB's for PICs & COM1/LPT1 PC I/O Interface Kits ;! Don McKenzie. 29 Ellesmere Cres., Tullamarine. 3043 Australia ;@ Tel +61 3 9338 6286 Mobile +61 19 939 799 donmckspam_OUTtbsa.com.au ;# Check My Promo Disk at http://rasi.lr.ttu.ee/~sis/mirror/don/ ;$ Type: 'finger @spam@donmckKILLspamtbsa.com.au|more' for more information.

On Thu, 2 Nov 1995, PETE KLAMMER said: Subject: : 32Kbyte NV FRAMs? > > From: Don McKenzie <KILLspamdonmckKILLspamtbsa.com.au> > > Subject: Re: 512 KByte of memory: EASIEST WAY!!! > > > > He said 512 Kilobytes!! -------------clip---------clip----------------------------- > Well, for adequate density/capacity, for one, eh? Sorry if I got anyone's > hopes up. -------------clip---------clip----------------------------- Hi, I have been following your threads on interfacing 512K x 8 memory to PICs. I have Dallas Semiconductor's 11 page data sheet for their 3 wire to bytewide bus interface 1280.ps (370k). The chip has the following features: * Adapts JEDEC bytewide memory to a 3-wire serial port * Supports 512k bytes of memory * 80-pin version provides arbitration mechanisms for dual port operation * CMOS circuitry for battery backup and battery operate applications * Cyclic redundancy check monitors serial transmission for error * Available in 44/80 pin quad flat pack for high density requirements A short description from data sheet page 1, is as follows: The DS1280 adds a 3-wire serial port to a bytewide static RAM, yet maintains the existing bytewide port. Memory capacity of up to 512K x 8 bytes can be addressed directly. Arbitration between the serial and bytewide port is accomplished by handshaking or using predictable idle time as an access window. The serial protocol requires a 6 byte protocol to set up memory transfers. Cyclic redundancy check circuitry is included to monitor serial data transmission error. The 3-wire serial port will correctly read and write any byte wide static RAM with an effective access time of 200ns. The serial interface uses bi-directional data pin (DQ), unlike other three/four wire interfaces which have separate Data In and Data Out pins. Data pins description follows: ___ RST RESET FOR SERIAL PORT Clk CLOCK INPUT FOR SERIAL PORT DQ DATA INPUT/OUTPUT FOR SERIAL PORT DQOE SERIAL PORT ACTIVE OUTPUT *AVAILABLE ONLY ON 44 PIN VERSION DQE SERIAL PORT ACTIVE OUTPUT *AVAILABLE ONLY ON 80 PIN VERSION ___ CEB SYSTEM BUS ENABLE *AVAILABLE ONLY ON 80 PIN VERSION ___ OEB SYSTEM BUS READ ENABLE *AVAILABLE ONLY ON 80 PIN VERSION ___ WEB SYSTEM BUS WRITE ENABLE *AVAILABLE ONLY ON 80 PIN VERSION A0B-A18B SYSTEM ADDRESS BUS *AVAILABLE ONLY ON 80 PIN VERSION D0B-D7B SYSTEM DATA BUS *AVAILABLE ONLY ON 80 PIN VERSION ___ CER RAM CHIP ENABLE ___ WER RAM WRITE ENABLE ___ OER RAM OUTPUT ENABLE A0R-A18R RAM ADDRESS BUS D0R-D7R RAM DATA BUS GND GROUND Vcc 5 VOLTS ---------------------------------------------------------------------------- ------ As you can see it is able to both access NV static ram, and the 80 pin version can allow access to system bus of another cpu. It appears to be good choice to expand an existing PIC design, which may have a serial interface already implemented, but other I/O pins commited to other tasks. It makes at most a single chip solution to expand a PIC or any 8 bit cpu to access additional ram. Dallas also has chips that combine the features for cpu/ram reset for power down or brown-out protection, with a real time clock that runs on 3V lithium power cells when your cpu/ram is in sleep mode. Dallas also have plug-in non/volatile read write cartridge with size up to 512K x 8 byte, which is ideal for data-logging. It can be inserted or removed by non-technical persons. It has manual read/write enable switch in cartridge, and has hot swap feature built-in. It is DS1217M, data sheet is 1217M.PS (postscript). You can retrieve full data sheets as well as application notes for these and other chips at: ftp.dalsemi.com/pub/datasheets/ regards ******************************************************************************** * Tom Brown E-Mail:RemoveMEtombrownTakeThisOuTindo.net.id * * Bumi Karang Indah Phone: 62-21-7508264 * * Jalan Karang Asri II, ************************************************** * Blok C2/#43, Lebak Bulus * "If something is worth doing, * * Jakarta, Seletan 12440 * It's worth doing right the first time" * * Indonesia * * ********************************************************************************

On Fri, 1 Dec 1995, Tommy Brown wrote: > On Thu, 2 Nov 1995, PETE KLAMMER said: > Subject: : 32Kbyte NV FRAMs? > > > From: Don McKenzie <spamBeGonedonmckspamBeGonetbsa.com.au> > > > Subject: Re: 512 KByte of memory: EASIEST WAY!!! > > > He said 512 Kilobytes!! > -------------clip---------clip----------------------------- > > Well, for adequate density/capacity, for one, eh? Sorry if I got anyone's > > hopes up. > -------------clip---------clip----------------------------- > > Hi, I have been following your threads on interfacing 512K x 8 memory > to PICs. > I have Dallas Semiconductor's 11 page data sheet for their 3 wire to > bytewide bus interface 1280.ps (370k). > The chip has the following features: > etc etc. > * Tom Brown I read through your description of this device and it sounds good, but I didn't notice a dollar sign anywhere. Is it cost effective Tommy? Also your lead for Gates Engineering in Singapore. Wasn't that 1 off prices you quoted in a previous message. They didn't quite understand where I was coming from. They work in 1000 off pcs. and $2000US minimum orders. Don McKenzie. 29 Ellesmere Cres., Tullamarine. 3043 Australia ETI PIC Basic, BS1/2 & Alternatives. 18/28 PIC protos with RS-232/485 Promo Disk http://rasi.lr.ttu.ee/~sis/mirror/don/ finger TakeThisOuTdonmckEraseMEspam_OUTtbsa.com.au for more info. VISA-MC-BC InfoFax 6 pages Inc cct: Voice then Fax +613 9338-2935 Password # 1111