Post by thread:Implementing I2C questions

Hello all, I am looking for more info on implementing I2C. I have read (well actually only scanned) the information sheets/app notes from Phillips and Microchip but they don't mention if this bus structure can be used for non-I2C slave devices such as an LCD display or switch matrix. The I2C structure looks very nice (at least to me) but it seems that it will only work with I2C-ready slave devices. If I could, I would really like to implement this structure with non-I2C devices. Does anyone know if this is possible and what kind of hardware decoding is needed. I am hoping to implement this with the PIC16F84 (the developer's "fav chip") Thanks in advance! Regards from Vancouver, B.C. CANADA (yep!....It's raining today!) -Randie "Still very new to PICs" Ohtsji /*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/ */ Randie Ohtsji /* /* Glenayre R&D, Vancouver, BC CANADA Phone: (604) 293-1611 x4555 */ */ Email: spam_OUTrohtsjiTakeThisOuTglenayre.com Fax: (604) 293-4317 /* */ ________ /* /* / ____/ /__ ____ ____ ___ _________ */ */ / /___/ / _ \/ __ \/ __ `/ / / / __/ _ \ /* /* / /_\ / / __/ / / / /_/ / /_/ / / / __/ */ */ \____/_/\___/_/ /_/\__,_/\__ /_/ \___/ /* /* ________________________/ / */ */ /_________________________/ /* /*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/*/

At 09:11 22.10.1997 -0700, you wrote: Hi, >The I2C structure looks very nice (at least to me) but it seems that it really is ! >it will only work with I2C-ready slave devices. If I could, I would >really like to implement this structure with non-I2C devices. Does >anyone know if this is possible and what kind of hardware decoding is Take the PCF8574 from Philips. It's an I2C to 8Bit parallel (and vice versa) interface chip. So you can connect the LCD to the PCF. With a little bit of code you can even derive serial clocking, most LCD-Modules need something like this. >needed. I am hoping to implement this with the PIC16F84 (the developer's >"fav chip") If you are only driving devices in slave mode I strongly recommend a PIC with hardware implemented I2C. It's much easier to get results this way instead of writing lots of I2C-code. So long Thomas =8-) ********************************************************** * Thomas Magin FON: ++49-761-4543-489 * * marquette-Hellige GmbH FAX: -507 * * Emergency Systems email: .....maginKILLspam@spam@hellige.de * * Munzinger Str. 3 * * D-79111 Freiburg / Germany * **********************************************************

Hi Thomas, > Take the PCF8574 from Philips. It's an I2C to 8Bit parallel (and vice versa) > interface chip. So you can connect the LCD to the PCF. With a little bit of > code you can even derive serial clocking, most LCD-Modules need something > like this. Thanks for the lead. I downloaded the data sheets from Philips and called the local rep to get me some real data books. Do you use a second PCF chip for control signals to the LCD? (ie. r/w, en, rs lines) What do you do for a switch matrix using I2C? Cheers, -Randie P.S. I still don't know if I2C is for me. I really like it, but I don't have any devices (including the micro) which use it. Maybe a serial EEPROM in the future but I just thinking about future addons for flexability. ----- Begin Included Message ----- >From maginKILLspamHELLIGE.DE Wed Oct 22 09:47:31 1997 X-Sender: magin@mailsrv Mime-Version: 1.0 Date: Wed, 22 Oct 1997 18:43:48 +0200 From: Thomas Magin <.....maginKILLspam.....HELLIGE.DE> Subject: Re: Implementing I2C questions To: EraseMEPICLISTspam_OUTTakeThisOuTMITVMA.MIT.EDU At 09:11 22.10.1997 -0700, you wrote: Hi, >The I2C structure looks very nice (at least to me) but it seems that it really is ! >it will only work with I2C-ready slave devices. If I could, I would >really like to implement this structure with non-I2C devices. Does >anyone know if this is possible and what kind of hardware decoding is Take the PCF8574 from Philips. It's an I2C to 8Bit parallel (and vice versa) interface chip. So you can connect the LCD to the PCF. With a little bit of code you can even derive serial clocking, most LCD-Modules need something like this. >needed. I am hoping to implement this with the PIC16F84 (the developer's >"fav chip") If you are only driving devices in slave mode I strongly recommend a PIC with hardware implemented I2C. It's much easier to get results this way instead of writing lots of I2C-code. So long Thomas =8-) ********************************************************** * Thomas Magin FON: ++49-761-4543-489 * * marquette-Hellige GmbH FAX: -507 * * Emergency Systems email: maginspam_OUThellige.de * * Munzinger Str. 3 * * D-79111 Freiburg / Germany * ********************************************************** ----- End Included Message -----

At 14:27 22.10.1997 -0700, you wrote: Hi, >Do you use a second PCF chip for control signals to the LCD? (ie. r/w, >en, rs lines) I don't use any PCF at all. I've only used it to play and examine the I2C (connecting switches and LEDs). Today the goal is to connect a couple of PICs to a PowerPC (the embedded version). > >What do you do for a switch matrix using I2C? Maybe there are some "off the shelf" keyboardcontrollers with integrated I2C available. Another pssibility might be to use a GAL for multiplexind and the PCF for converting it. So long Thomas =8-) ********************************************************** * Thomas Magin FON: ++49-761-4543-489 * * marquette-Hellige GmbH FAX: -507 * * Emergency Systems email: KILLspammaginKILLspamhellige.de * * Munzinger Str. 3 * * D-79111 Freiburg / Germany * **********************************************************

-----Original Message----- From: Randie Ohtsji [4555] <RemoveMErohtsjiTakeThisOuTGLENVAN.GLENAYRE.COM> To: spamBeGonePICLISTspamBeGoneMITVMA.MIT.EDU <TakeThisOuTPICLISTEraseMEspam_OUTMITVMA.MIT.EDU> Date: Thursday, 23 October 1997 7:01 Subject: Re: Implementing I2C questions >Hi Thomas, > >> Take the PCF8574 from Philips. It's an I2C to 8Bit parallel (and vice versa) >> interface chip. So you can connect the LCD to the PCF. With a little bit of >> code you can even derive serial clocking, most LCD-Modules need something >> like this. > >Thanks for the lead. I downloaded the data sheets from Philips and called >the local rep to get me some real data books. > >Do you use a second PCF chip for control signals to the LCD? (ie. r/w, >en, rs lines) You don't need to. Assume you are sending bits 0 - 3 to an LCD as data, bit 4 - en, bit 5 - rw, bit 6 strobe? msb first - write the nibble 0x0d assume active hi for enable , strobe, write 0110000 - device enabled, write enabled 0111101 - data set, still as above 1111101 - ditto - strobe hi 0111101 - ditto strobe lo do it again from line 2 > >What do you do for a switch matrix using I2C? > There's an i2c version. <snip> >it really is ! > >>it will only work with I2C-ready slave devices. If I could, I would >>really like to implement this structure with non-I2C devices. Does >>anyone know if this is possible and what kind of hardware decoding is > >Take the PCF8574 from Philips. It's an I2C to 8Bit parallel (and vice versa) {Quote hidden}>interface chip. So you can connect the LCD to the PCF. With a little bit of >code you can even derive serial clocking, most LCD-Modules need something >like this. > >>needed. I am hoping to implement this with the PIC16F84 (the developer's >>"fav chip") > >If you are only driving devices in slave mode I strongly recommend a PIC >with hardware implemented I2C. It's much easier to get results this way >instead of writing lots of I2C-code. > s/w for doing it aint that hard. MikeS <RemoveMEmikesmith_ozTakeThisOuTrelaymail.net>