Post by thread:[PIC] SSPIF ?

PIC 16F87x, Unlike the USART decription, the description of the MSSP (at least the SPI-mode) is very vague to me. Does filling of SSPBUF (for sending a byte in SPI-master mode) clear the SSPIF ? Or has the to be done by code? To me it seems even more logical that: reading or writing the SSPBUF will clear the SSPIF. Is this true ?? thanks Stef -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> Does filling of SSPBUF (for sending a byte in SPI-master mode) clear the > SSPIF ? > Or has the to be done by code? With the 18F series at least, this isn't the case even though the documentation indicates it will get cleared. I implemented this bit of code and it works great (at least on the 18F series in my application). movff SPIByte1, SSPBUF ; Write out some data SPIwaitLoop btfss PIR1, SSPIF ; Wait for SPI to finish goto SPIwaitLoop bcf PIR1,SSPIF movff SPIByte2, SSPBUF ; Write out some data SPIwaitLoop2 btfss PIR1, SSPIF ; Wait for SPI to finish goto SPIwaitLoop2 bcf PIR1,SSPIF -->Neil ------------------------------------------------------------------------------- Neil Bradley In the land of the blind, the one eyed man is not Synthcom Systems, Inc. king - he's a prisoner. ICQ #29402898 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Neil Bradley wrote: >>Does filling of SSPBUF (for sending a byte in SPI-master mode) clear the >>SSPIF ? >>Or has the to be done by code? >> >> > >With the 18F series at least, this isn't the case even though the >documentation indicates it will get cleared. I implemented this bit of >code and it works great (at least on the 18F series in my application). > > Thanks Neil, but I wasn't looking for the "safe" code, I'm writing a simulator, I'ld like to know the "exact" answer, so I can even signal when the "not safe" code is used ;-) Stef Mientki -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> >With the 18F series at least, this isn't the case even though the > >documentation indicates it will get cleared. I implemented this bit of > >code and it works great (at least on the 18F series in my application). > but I wasn't looking for the "safe" code, > I'm writing a simulator, I'ld like to know the "exact" answer, > so I can even signal when the "not safe" code is used ;-) With the 18F series, the docs are flatly wrong. It isn't automatically cleared (it MUST be done in software) I can't speak about other PICs, though - they may behave differently. -->Neil ------------------------------------------------------------------------------- Neil Bradley In the land of the blind, the one eyed man is not Synthcom Systems, Inc. king - he's a prisoner. ICQ #29402898 -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

What part of "(must be cleared in software)" don't you understand? * | __O Thomas C. Sefranek spam_OUTWA1RHPTakeThisOuTARRL.NET |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org > {Original Message removed}

Thomas C. Sefranek wrote: >What part of "(must be cleared in software)" don't you understand? > No part ;-) But I love to know where I can find it in the documentation !! Stef Mientki {Quote hidden}> > * > | __O Thomas C. Sefranek .....WA1RHPKILLspam@spam@ARRL.NET > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz > >hamradio.cmcorp.com/inventory/Inventory.html >http://www.harvardrepeater.org > > > >>{Original Message removed}

I found it in the bit definition of the SSPIF (SPI IRQ flag bit). That's why I quoted it to you. I don't have the sheet in front of me or I'd tell you the page. * | __O Thomas C. Sefranek WA1RHPKILLspamARRL.NET |_-\<,_ Amateur Radio Operator: WA1RHP (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz hamradio.cmcorp.com/inventory/Inventory.html http://www.harvardrepeater.org > {Original Message removed}

Thomas C. Sefranek wrote: >I found it in the bit definition of the SSPIF (SPI IRQ flag bit). >That's why I quoted it to you. I don't have the sheet in front of me >or I'd tell you the page. > thanks, I looked in the I2C description, and there indeed the speak (sometimes !) of i.e page 74 / DS30292 "read the SSPBUF and vlear flag bit SPPIF" So I'll assume it's the same for SPI ! Stef {Quote hidden}> > * > | __O Thomas C. Sefranek .....WA1RHPKILLspam.....ARRL.NET > |_-\<,_ Amateur Radio Operator: WA1RHP > (*)/ (*) Bicycle mobile on 145.41, 448.625 MHz > >hamradio.cmcorp.com/inventory/Inventory.html >http://www.harvardrepeater.org > > > >>{Original Message removed}

> >I found it in the bit definition of the SSPIF (SPI IRQ flag bit). > >That's why I quoted it to you. I don't have the sheet in front of me > >or I'd tell you the page. > > > thanks, > I looked in the I2C description, and there indeed the speak (sometimes > !) of > i.e page 74 / DS30292 > "read the SSPBUF and vlear flag bit SPPIF" > > So I'll assume it's the same for SPI ! Go ahead and assume it - it's a mistake. I can tell you from experience as of yesterday on the 18F series that it doesn't work this way - data sheet be damned. -->Neil ------------------------------------------------------------------------------- Neil Bradley In the land of the blind, the one eyed man is not Synthcom Systems, Inc. king - he's a prisoner. ICQ #29402898 -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

>Go ahead and assume it - it's a mistake. I can tell you from experience as >of yesterday on the 18F series that it doesn't work this way - data sheet >be damned. > >-->Neil Neil, If you are referring to this line: (DS30292C-page 74) 3. Read the SSPBUF register (clears bit BF) and clear flag bit SSPIF. It is a bit ambiguous. This easily could be read that "reading the sspbuf reg clears the flags..." but on the very next page is: An SSP interrupt is generated for each data transfer byte. The SSPIF flag bit must be cleared in software HTH Tom M -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

On Sat, 15 Mar 2003, Neil Bradley wrote: > > >I found it in the bit definition of the SSPIF (SPI IRQ flag bit). > > >That's why I quoted it to you. I don't have the sheet in front of me > > >or I'd tell you the page. > > > > > thanks, > > I looked in the I2C description, and there indeed the speak (sometimes > > !) of > > i.e page 74 / DS30292 > > "read the SSPBUF and vlear flag bit SPPIF" > > > > So I'll assume it's the same for SPI ! > > Go ahead and assume it - it's a mistake. I can tell you from experience as > of yesterday on the 18F series that it doesn't work this way - data sheet > be damned. This is what I have in my SPI interrupt handler: MOVFF SSPBUF,PLUSW2 ;Get the newly received byte ;(Clears the "buffer full" flag too) BCF PIR1,SSPIF ;Clear the interrupt flag I don't look at the BF bit, but for some reason in the past I felt compelled to add the comment. Scott -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.