Post by thread:IIC Master using 16C7x

Hi everyone, I am having trouble understanding the data sheet on the 16c7X IIC module. I would like to run my 74JW as a master but from the data sheet it looks like I have to implement the master mode completely in software. Is this correct? If not, what do I have to configure the SSPCON with... 1011 for I2C start and stop bit interrupts enabled (slave idle)? Thanks for any help in advance, Brian.

Sorry Brian, I2C Master Mode doesn't work on the current PICs (although it will work on the 17C56 (?) which is soon to be out). I've heard somebody say that they got a PIC to work as a Master using Slave Mode and a clock output, but I haven't seen any code for it as yet. myke {Quote hidden}>Hi everyone, > I am having trouble understanding the data sheet on the 16c7X IIC >module. I would like to run my 74JW as a master but from the data sheet it >looks like I have to implement the master mode completely in software. Is >this correct? If not, what do I have to configure the SSPCON with... 1011 >for I2C start and stop bit interrupts enabled (slave idle)? > >Thanks for any help in advance, > Brian. > > "Some people say that foreign cars handle best, while others say domestic. For my money, nothing handles as well as a rental car." - P.J. O'Rourke

---------- > From: myke predko <spam_OUTmykeTakeThisOuTPASSPORT.CA> > To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Subject: Re: IIC Master using 16C7x > Date: Wednesday, 9 April 1997 06:44 > > Sorry Brian, I2C Master Mode doesn't work on the current PICs (although it > will work on the 17C56 (?) which is soon to be out). > > I've heard somebody say that they got a PIC to work as a Master using Slave > Mode and a clock output, but I haven't seen any code for it as yet. > CCS compiler seems to emit code for both master & slave (master on any pins, slave on h/w ssi only) I've used master mode on this compiler, and it reads/writes 24c65 EEPROM's ok - that means the PIC is running master mode, right? MikeS

At 11:15 09.04.97 +0930, you wrote: >CCS compiler seems to emit code for both master & slave (master on any >pins, slave on h/w ssi only) I've used master mode on this compiler, and >it reads/writes 24c65 EEPROM's ok - that means the PIC is running master >mode, right? > >MikeS > Yes, in pure software, without hardware support. -- Wolfram +-----------------------------------------------------+ | Wolfram Liebchen | | Forschungsinstitut fŸr Optik, TŸbingen, Deutschland | | liebchenKILLspamffo.fgan.de | +-----------------------------------------------------+

re: 16C74 and I2C Brian, this is not much help but I've been working on a 16C74-based weather station and, amongst other things, it talks to remote displays via a serial bus. The remotes are 16C84s. I tried implementing I2C using the 16C74 hardware and software in the remotes. I had a lot of problems so I went with an SPI-style 3-wire interface implemented in software using the same SPI-designated 16C74 pins, and it's working fine. I chose not to use the 74's SPI as I'm talking to both custom and standard SPI devices. Well this just be my ignorance but my experience with PIC's and I2C has not been very successful. - Tom At 05:31 PM 4/8/97 PDT, you wrote: {Quote hidden}>Hi everyone, > I am having trouble understanding the data sheet on the 16c7X IIC >module. I would like to run my 74JW as a master but from the data sheet it >looks like I have to implement the master mode completely in software. Is >this correct? If not, what do I have to configure the SSPCON with... 1011 >for I2C start and stop bit interrupts enabled (slave idle)? > >Thanks for any help in advance, > Brian. > >

Tom Handley wrote: > > re: 16C74 and I2C > > Brian, this is not much help but I've been working on a 16C74-based > weather station and, amongst other things, it talks to remote displays > via a serial bus. The remotes are 16C84s. I tried implementing I2C using > the 16C74 hardware and software in the remotes. I had a lot of problems > so I went with an SPI-style 3-wire interface implemented in software using > the same SPI-designated 16C74 pins, and it's working fine. I chose not to > use the 74's SPI as I'm talking to both custom and standard SPI devices. > Well this just be my ignorance but my experience with PIC's and I2C has not > been very successful. If you use the IIC slave mode in a lower end chip (software implementation), you have to be very careful. Master mode is trivial, but slave mode can get extremely tricky if you have a lot of other processing to do. -- Friendly Regards Tjaart van der Walt .....tjaartKILLspam.....wasp.co.za _____________________________________________________________ | Another sun-deprived R&D Engineer slaving away in a dungeon | | WASP International http://wasp.co.za | | GSM and GPS value-added applications | | Voice : +27-(0)11-622-8686 | Fax : +27-(0)11-622-8686 | |_____________________________________________________________|

From: Wolfram Liebchen <EraseMEliebchenspam_OUTTakeThisOuTFFO.FGAN.DE> To: PICLISTspam_OUTMITVMA.MIT.EDU Subject: Re: IIC Master using 16C7x Date: Wednesday, 9 April 1997 16:46 At 11:15 09.04.97 +0930, you wrote: >>CCS compiler seems to emit code for both master & slave (master on any >>pins, slave on h/w ssi only) I've used master mode on this compiler, and >>it reads/writes 24c65 EEPROM's ok - that means the PIC is running master >>mode, right? >Yes, in pure software, without hardware support. If you use the ssi pins, CCS's book says it implements it using h/w. My app isn't using h/w, for various reasons. Do you mean if I *did* use the h/w version, I would encounter problems? I'd like to know if this is the case, as I was thinking of using the h/w version in the future. MikeS