Post by thread:serial memory

For a new application under analysis, we will need about 2K of RAM memory for data arrays storage. Serial memory could be a solution, as it appears that a 20MHZ 16C73 we are planning to use will be fast enough for the application, with spare time for serial data handling. Have searched the Microchip 1995/1996 data book, but have only found serial EEPROM's. Is there anybody with experience on I2C type serial RAM, volatile equivalent to the microchip I2C serial EEprom family???? Pls. provide details juan

Juan Abba <spam_OUTjuanabbaTakeThisOuTAX.APC.ORG> wrote: > Is there anybody with experience on I2C type serial RAM, volatile equivalent to > the microchip I2C serial EEprom family???? I don't have any experience with it, but Philips have a 256x8 I2C interfaced RAM device. You can use 8 on the I2C bus (maybe more) which would give you the 2K you need. The part no, is PCF8570 - you can get a data sheet from http://www.semiconductors.philips.com/ps/acrobat/3041.pdf. -- Clyde Smith-Stubbs | HI-TECH Software, | Voice: +61 7 3300 5011 .....clydeKILLspam@spam@hitech.com.au | P.O. Box 103, Alderley, | Fax: +61 7 3300 5246 http://www.hitech.com.au | QLD, 4051, AUSTRALIA. | BBS: +61 7 3300 5235 ---------------------------------------------------------------------------- For info on the World's best C cross compilers for embedded systems, point your WWW browser at http://www.hitech.com.au, or email infoKILLspamhitech.com.au

On Tue, 16 Apr 1996, Juan Abba wrote: > For a new application under analysis, we will need about 2K of RAM memory for > data arrays storage. > > Serial memory could be a solution, as it appears that a 20MHZ 16C73 we are > planning to use will be fast enough for the application, with spare time for > serial data handling. > > Have searched the Microchip 1995/1996 data book, but have only found serial > EEPROM's. I also looked at this and decided that it would be too slow and too small, so I added an external SRAM 32K and wrote a small program that will be able to read and write to it using some I/O bits. chaipi \\\|/// \\ ~ ~ // ( @ @ ) ----------------------------oOOo-(_)-oOOo-------------------------------------- ! ! ! Chaipi Wijnbergen ! ! Electronics/Computer Eng. M.Sc. Tel : +972-8-9343079 ! ! Optical Imaging Laboratory Fax : +972-8-9344129 ! ! Brain Research Center Email : .....chaipiKILLspam.....tohu0.weizmann.ac.il ! ! Weizmann Institute of Science URL : http://www.weizmann.ac.il/~chaipi ! ! Rehovot 76100 ISRAEL IPhone : chaipi ! ! ! ------------------------------------Oooo.-------------------------------------- .oooO ( ) ( ) ) / \ ( (_/ \_)

> > On Tue, 16 Apr 1996, Juan Abba wrote: > > > For a new application under analysis, we will need about 2K of RAM memory for > > data arrays storage. > > > > Serial memory could be a solution, as it appears that a 20MHZ 16C73 we are > > planning to use will be fast enough for the application, with spare time for > > serial data handling. > > > > Have searched the Microchip 1995/1996 data book, but have only found serial > > EEPROM's. > > I also looked at this and decided that it would be too slow and too > small, so I added an external SRAM 32K and wrote a small program that > will be able to read and write to it using some I/O bits. It not only takes a few I/O bits (11-12 at a minimum if you use external latches and a decoder) but quite a lot of board real estate with the extra chips offboard. It's a good solution if you need fast access and a lot of memory and most importantly you can spare the board real-estate. I've come across another possible solution: The Dallas SemiConductor RAMPort. It's a 24 pin 600 mil 2K static ram specifically designed for attachment to microcontrollers because it not only internalizes the previously mentioned latches and decoder, but it also duplicates the 8 bit port you need to talk to it. So instead of losing 10 I/O pins (8 data, 2 control) you actually only lose the 2 control pins because the 8 data pins are duplicated by the part. The parts use a 3 byte sequence to read and write so it's quite fast relative to a serially accessed part. The part numbers are DS1380 and DS1381. The 1381 has a built in lithium battery for data retention while the 1380 has battery pins to attach an external pattery. $9 and $11 in singles through the DalSemi extremely experimenter friendly 1-800 line (factory direct, no minimum order, credit card, fast delivery, what more can you ask for). I plan to use the part in an upcoming project soon to be announced here. Hope this helps, BAJ

In message <EraseME829627543.21060.0spam_OUTTakeThisOuTvms.dc.lsoft.com> PICLISTspam_OUTMITVMA.MIT.EDU writes: > For a new application under analysis, we will need about 2K of RAM memory for > data arrays storage. > > Serial memory could be a solution, as it appears that a 20MHZ 16C73 we are > planning to use will be fast enough for the application, with spare time for > serial data handling. > > Have searched the Microchip 1995/1996 data book, but have only found serial > EEPROM's. > > Is there anybody with experience on I2C type serial RAM, volatile equivalent to > the microchip I2C serial EEprom family???? > Pls. provide details > > juan, You could try a RAMTron serial FRAM. They behave like EEProms, but have *NO* write delay and 10 billion (10^10) cycle read/write endurance figure. The FM24C16 is a 2K by 8 device with I2C at 100kHz and 400kHz. I've used them before with no problems. The data book gives a 800 number: (800) 545-FRAM/DRAM. Regards, Mike Watson -- Mayes uk

Juan Abba <@spam@juanabbaKILLspamAX.APC.ORG> wrote: > Is there anybody with experience on I2C type serial RAM, volatile equivalent to > the microchip I2C serial EEprom family???? Hi, Here is the code to drive an I2C RAM/EEPROM (PIC16C54..57), you can also use 93C46( or 06 or ...) EEPROM type, but the protocol is different. Be carrefull about timing, I2C application note said I2C Clock can run only at 100KHz ! ;***************************************************************************** ;************** RAM / EEProm ACCESS ROUTINE on I2C Bus ********************** ; HCK = PortA.0 ; SDA = PortA.1 (In/Out) ;***************************************************************************** I2C_Address equ %10100000 ; ITEM address on I2C Line ;---------------- REGISTERS Address equ $18 ; Address to Read/Write DataHi equ $19 ; Word DATA (16Bits) DataLo equ $1A Data1 equ $10 Data2 equ $11 TempTxRx equ $1B ; Temporary register I2CCnt equ $1C ; Counter to send/Receive bits ;---------------- CONST I2CSetOUT equ %0000 ; Value to configure SDA as OUTPUT I2CSetIN equ %0010 ; Value to configure SDA as INPUT I2CPort equ 5 ; PORT A is I2CPort HCK equ 0 ; PortA.0 SDA equ 1 ; PortA.1 I2CAckWait equ 20 ; WAIT time to check ACKNOWLEDGE I2CError equ 1 ; return value if error I2COk equ 0 ; return value if OK ;****************************************************************************** ;***************************************************************************** ; RAM / EEProm ACCESS ROUTINE on I2C Bus ; HCK = PortA.0 ; SDA = PortA.1 (In/Out) ;***************************************************************************** ; WRITE WORD Data to I2C-RAM/EPROM ; Address : Address of the 2 Byte to WRITE ; DataHi : Hi Data ; DataLo : Lo Data I2CWriteData call I2CStart ; START BIT movlw I2C_Address ; Put SLAVE address on I2C line iorlw %00000000 ; To WRITE a DATA at ADDRESS movwf TempTXRX ; TempTXRX = Address of I2C Item call TxData ; Transfert DATA on SDA Line call AckWait0 ; Wait for Acknowledge btfss STATUS,2 ; Skip if Z=1 goto I2CStop movf Address,W ; Address to Access in W movwf TempTXRX ; Address to Access in W call TxData ; Transfert DATA on SDA Line call AckWait0 ; Wait for Acknowledge iorlw 0 btfss STATUS,2 ; Skip if Z=1 goto I2CStop movf Data1,W ; DataLO to WRITE in W movwf TempTXRX call TxData ; Transfert DATA on SDA Line call AckWait0 ; Wait for Acknowledge iorlw 0 btfss STATUS,2 ; Skip if Z=1 goto I2CStop movf Data2,W ; DataHI to WRITE in W movwf TempTXRX call TxData ; Transfert DATA on SDA Line call AckWait0 ; Wait for Acknowledge iorlw 0 call I2CStop ; STOP BIT retlw I2COk ;***************************************************************************** ; Output TempTXRX on SDA Line TXData movlw I2CSetOut ; Set SDA as OUTPUT tris A bcf I2CPort,SDA ; SDA = 0 movlw 8 ; I2CCnt = 8 movwf I2CCnt TXDataLoop bcf I2CPort,SDA ; SDA = 0 rlf TempTXRX btfsc STATUS,CY ; Skip if CARRY=0 bsf I2CPort,SDA bsf I2CPort,HCK ; HCK = 1 nop nop nop nop bcf I2CPort,HCK ; HCK = 0 decfsz I2CCnt goto TXDataLoop nop nop retlw I2COk ;***************************************************************************** ; Read TempTXRX on SDA Line RXData movlw I2CSetIN ; Set SDA as INPUT tris A movlw 8 ; I2CCnt = 8 movwf I2CCnt clrf TempTXRX RXDataLoop bsf I2CPort,HCK ; HCK = 1 bcf STATUS,CY ; CARRY = 0 btfsc I2CPort,SDA ; Skip if SDA=0 bsf STATUS,CY rlf TempTXRX nop bcf I2CPort,HCK ; HCK = 0 nop nop nop decfsz I2CCnt goto RXDataLoop retlw I2COk ;***************************************************************************** ; Wait k Cycle for Acknowledge from slave ACKWait0 movlw I2CSetIN tris A bsf I2CPort,HCK ; HCK = 1 movlw I2CAckWait ; I2CCnt = I2CAckWait (Wait TIME) movf I2CCnt ACKLoop0 btfss I2CPort,SDA ; Skip if SDA = 1 goto AckOk0 decfsz I2CCnt goto AckLoop0 bcf I2CPort,HCK ; HCK = 0 retlw I2CError ACKOk0 bcf I2CPort,HCK ; HCK = 0 retlw I2COk ;***************************************************************************** ; Wait k Cycle for Acknowledge from MASTER, if SDA line goes down then, an ; error occur (because SLAVE want to interrupt transmission) ACKWait1 movlw I2CSetOut tris A bcf I2CPort,SDA ; HCK = 0 bsf I2CPort,HCK ; HCK = 1 nop nop nop nop bcf I2CPort,HCK ; HCK = 0 nop nop retlw I2COk ;***************************************************************************** ACKWaitEnd movlw I2CSetIN tris A bsf I2CPort,HCK ; HCK = 1 nop nop nop nop btfss I2CPort,SDA ; Skip if SDA = 1 goto AckEr1 bcf I2CPort,HCK ; HCK = 0 retlw I2COk ACKEr1 bcf I2CPort,HCK ; HCK = 0 retlw I2CError ;***************************************************************************** ; OutPut the Start CONDITION I2CStart movlw I2CSetOut tris A bsf I2CPort,SDA ; SDA = 1 bsf I2CPort,HCK ; HCK = 1 nop nop nop nop bcf I2CPort,SDA ; SDA = 0 nop nop nop nop bcf I2CPort,HCK ; HCK = 0 nop retlw 0 ;***************************************************************************** ; OutPut the Stop CONDITION I2CStop movlw I2CSetOut ; Set SDA as OUTPUT tris A bcf I2CPort,SDA ; SDA = 0 bsf I2CPort,HCK ; HCK = 1 nop nop nop nop bsf I2CPort,SDA ; SDA = 1 nop nop nop nop bcf I2CPort,HCK ; HCK = 0 nop retlw I2CError ; An ERROR is finishig by a STOP Condition ;***************************************************************************** ; END OF I2C CODE

Does anybody know of a way to combine a PIC with a really large chunk of serial memory, much more than 8 kilobytes? Do you know what serial memory chips are available, and practical? EEPROM or FLASH would do, it's got to be non-volatile memory. Arvi Karhumaki EMail: KILLspamarviKILLspamvistacom.fi Support Technician Phone: +358-9-6226 2325 Vista Communication Instruments

www.atmel.com and follow the links for DataFlash At 04:46 PM 7/27/98 +0300, you wrote: {Quote hidden}>Does anybody know of a way to combine a PIC with a really large chunk of >serial memory, much more than 8 kilobytes? Do you know what serial memory >chips are available, and practical? EEPROM or FLASH would do, it's got to be >non-volatile memory. > > > >Arvi Karhumaki EMail: RemoveMEarviTakeThisOuTvistacom.fi >Support Technician Phone: +358-9-6226 2325 >Vista Communication Instruments > > ================================================================== Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA ==================================================================

The Microchip 24LC256 (& associated chips) family have fairly large capacities & are pretty easy to interface to (2-wire interface); See specs down from http://www.microchip.com/0/Lit/Memory/index.htm, for the larger chips see http://www.microchip.com/0/Lit/Memory/IC/64to128/index.htm. The 24LC256 is a 32k byte (8-bit bytes) i.e. 256k bit part. 64-byte page mode available. It's available in DIP-08 or SOIC-08 packaging, which is nice! $3ish in quantity. For one project, the customer (second alpha tester) feels we need 1/2 megabyte of SEEProm, so we're looking at either that part, 16 in parallel of 'em, which would take 3 PIC pins; or alternately at the Atmel DataFlash parts at http://www.atmel.com/atmel/products/select15.htm, for the first manual page of their 512k byte i.e. 4 Megabit part, see http://www.atmel.com/atmel/postscript/first_page/doc0803a.gif; They go from 2 megabits, up to 16 megabits on one 2.7V part (!) Disadvantages I can see so far over Microchip parts are size (soic-28 vs. -08, also in TSOP-28 and PLCC-32 packages) and it's a bit harder to use, 2048 264-byte pages, not byte accesses; advantages are it's fast! (10 MHz max clock rate), & lots of data in one chip, don't have to run 16 24LC256's for the same storage, and cheaper ($10 for a half megabyte instead of $50ish for 16, 24LC parts.) Atmel has regular Serial EEProms at http://www.atmel.com/atmel/products/prod6.htm, also. 1k bit up to 256 k bit, I haven't looked at those much, the Microchip parts may be a smidge easier to use? but maybe these are more versatile?, don't know pricing but imagine it's comparable. (Personally I still think we could get by with 2 24LC256'es, but, "The customer's always right." Ack!) Mark Willis, spamBeGonemwillisspamBeGonenwlink.com Arvi Karhumaki wrote: > > Does anybody know of a way to combine a PIC with a really large chunk of > serial memory, much more than 8 kilobytes? Do you know what serial memory > chips are available, and practical? EEPROM or FLASH would do, it's got to be > non-volatile memory. > > Arvi Karhumaki EMail: TakeThisOuTarviEraseMEspam_OUTvistacom.fi > Support Technician Phone: +358-9-6226 2325 > Vista Communication Instruments