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SteveS
Joined: 27 Oct 2003
Posts: 126
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| PICs with built-in I2C |
 Posted: Sat Jun 12, 2004 9:47 am |
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I did a search on Microchip's site to find what small 16F or 18F parts there were with built-in I2C. Maybe I'm missing something but they only show a few parts - all big parts or new ones. But I know there are others - so can anyone suggest the smallest 16F or 18F parts with built-in I2C - I need to do slave mode.
Meanwhile- I'm rambling thru the datasheets....
TIA,
SteveS |
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| try this |
| Posted: Sat Jun 12, 2004 10:27 am |
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pic18F242 or 252 the SPI doubles as I2C
hansw |
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ttelmah
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| Re: PICs with built-in I2C |
| Posted: Sat Jun 12, 2004 10:42 am |
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| SteveS wrote: | I did a search on Microchip's site to find what small 16F or 18F parts there were with built-in I2C. Maybe I'm missing something but they only show a few parts - all big parts or new ones. But I know there are others - so can anyone suggest the smallest 16F or 18F parts with built-in I2C - I need to do slave mode.
Meanwhile- I'm rambling thru the datasheets....
TIA,
SteveS |
The smallest 'current' parts with hardware I2C, that I can think of, is the 18F818/9, in 18 pin. Their search engine is awful in this regard, if you specify '<=28 pins', and 'I2C interface', it finds no parts, yet these exist...
Best Wishes |
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rnielsen
Joined: 23 Sep 2003
Posts: 852
Location: Utah
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| Posted: Mon Jun 14, 2004 8:38 am |
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I've used the following PIC's for I2C communications:
18F452(40 pin), 16F87(18 pin) and 16F76(28 pin). |
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SteveS
Joined: 27 Oct 2003
Posts: 126
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| Posted: Mon Jun 14, 2004 9:47 am |
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Thanks all -
When I went to Microchip site - it was 'cool, they added parameter look-up', but as ttelmah states, it is truly awful. I knew I had used other parts before that didn't show up. I feel sorry for someone new to PICs, they might do the search and just give up. I was hoping it was me and the way I searched, but no.
Now I get to try to make sense out of all the posts on slave mode problems...
- SteveS |
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Ttelmah
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| Posted: Mon Jun 14, 2004 10:25 am |
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| SteveS wrote: | Thanks all -
When I went to Microchip site - it was 'cool, they added parameter look-up', but as ttelmah states, it is truly awful. I knew I had used other parts before that didn't show up. I feel sorry for someone new to PICs, they might do the search and just give up. I was hoping it was me and the way I searched, but no.
Now I get to try to make sense out of all the posts on slave mode problems...
- SteveS |
The biggest core 'problem' I can think of is the damn long time it takes for the slave to respond to an interrupt, and be ready with a reply (assuming you are using a 'read' command). Just how long this truly is, especially if you have other interrupt handler, which the processor might be executing at the time, is a real 'pain' when you are used to hardware systems that can respond on the very next clock...
Combine this with a few 'oddities' in the way the CCS functions are structured, stir gently, and you have the core of most slave problems...
Hope you get it working how you want.
Best Wishes |
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SteveS
Joined: 27 Oct 2003
Posts: 126
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| Posted: Mon Jun 14, 2004 11:47 am |
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Thanks for the heads up - it will be a write-only-device - I need to make an SPI peripheral look like an I2C peripheral. Thats why I was looking for min pins - only need 5 or 6...
- SteveS |
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