Probably a bit over his head at the moment, but....Originally Posted by mackrackit
http://www.picbasic.co.uk/forum/showthread.php?t=7038
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Probably a bit over his head at the moment, but....
http://www.picbasic.co.uk/forum/showthread.php?t=7038
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I thought about that, but after looking at the data sheet for the MCP23S17 I am not so sure he wants to go there yet either. The MCP23S17 appears to be programmable or at least configurable. Looks like a fun chip.
From the data sheet:
The MCP23017/MCP23S17 (MCP23X17) device
family provides 16-bit, general purpose parallel I/O
expansion for I2C bus or SPI applications. The two
devices differ only in the serial interface.
• MCP23017 – I2C interface
• MCP23S17 – SPI interface
The MCP23X17 consists of multiple 8-bit configuration
registers for input, output and polarity selection. The
system master can enable the I/Os as either inputs or
outputs by writing the I/O configuration bits (IODIRA/B).
The data for each input or output is kept in the corre-
sponding input or output register. The polarity of the
Input Port register can be inverted with the Polarity
Inversion register. All registers can be read by the
system master.
The 16-bit I/O port functionally consists of two 8-bit
ports (PORTA and PORTB). The MCP23X17 can be
configured to operate in the 8-bit or 16-bit modes via
IOCON.BANK.
There are two interrupt pins, INTA and INTB, that can
be associated with their respective ports, or can be
logically OR’ed together so that both pins will activate if
either port causes an interrupt.
Dave
Always wear safety glasses while programming.
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It is a handy chip to have around, especially (in my case) just to use to trip MOSFETs around. Keeps anything crazy away from my PICs. A bit spendy compared to buying a large-ish I/O count PIC around, but so EEAASSYY to hook up...
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I would rather not hack the board up at this point....
If I could get this all striaght in my haed I know I can get the LDC display working...
Lookint at the expander datasheet and the demo board schematic it looks like LCD Data Lines (DB0B7) are connected to the GPIO lines (GPB0:GPB7). LCD RD is on GPA7 and LCD E is on GPA6.
The Pic is connected to the expander like this:
PIC Expander
RC3 --> SCK
RC5 --> SI
RF6 --> Reset
Knowing that How do I cammand the expander to do what I want it to do?
Thanks for all you help so far... it has been GREAT!!
Last edited by Frozen001; - 8th August 2008 at 20:43.
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Re-check post #8 and you might get a couple of good ideas there. It might be possible to do what is suggested there. Again, not 100% sure. Maybe when I get home, I'll pour over the schematics, see if the LCD connections and that port can be made to provide all the power/ground/control/data lines to run an LCD.
Does that LCD on the Microchip board unplug or is it hard soldered?
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It is hard soldered....
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Well, then I guess I'd check around the microchip forums a bit and see if you can find any 'libraries' to handle the LCD for you on that board, that is if you don't want to write the code yourself.
Using the LCD as it sits on that board can be done...it's not impossible by any stretch. It's just that you'll have to do all the leg work.
First thing you've got to do is get your hands on the datasheets for the I/O expander and the LCD itself, which as I said before is most likely a Hitachi 44780 parallel input compatible LCD, almost any datasheet for an LCD with 14 or 16 pins on the inputs will most likely work just fine. Because without knowing how to run the I/O expander or the LCD, you'll be stuck.The Pic is connected to the expander like this:
PIC Expander
RC3 --> SCK
RC5 --> SI
RF6 --> Reset
Knowing that How do I cammand the expander to do what I want it to do?
But for now, maybe hang some LEDs off the I/O outputs of the expander. Once you can command that thing to do whatever you want, the LCD will be close behind...
Last edited by skimask; - 8th August 2008 at 21:08.
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I wouldn't hack it up, I would set it aside until you catch up to it, You will have a much easier time learning if you use an PIC with a simpler architecture like 16F648A. I like that one because it is simple but not useless, nothing tough to get going and has 4k space. You can get an LCD for about $10 from this vendor. http://cgi.ebay.com/20x4-LCD-Module-...QQcmdZViewItemI would rather not hack the board up at this point....
If I could get this all striaght in my haed I know I can get the LDC display working...
Lookint at the expander datasheet and the demo board schematic it looks like LCD Data Lines (DB0
The Pic is connected to the expander like this:
PIC Expander
RC3 --> SCK
RC5 --> SI
RF6 --> Reset
Knowing that How do I cammand the expander to do what I want it to do?
Thanks for all you help so far... it has been GREAT!!
I buy from him pretty regularly.
If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
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Gold is the money of kings, silver is the money of gentlemen, barter is the money of peasants - but debt is the money of slaves
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There simply is no "Happy Spam" If you do it you will disappear from this forum.
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I would forget about the on-board LCD for the time being and get some experience using one wired in parallel (which is well documented). When you have that knowledge under your belt then think about tackling the on-board one.
PICs offer so many functions and possibilities It is tempting to try to take on to much at once. If you do, you are likely to be frustrated and spend a lot of time getting nowhere. However, take everything one step at a time and you will progress rapidly.
Best of luck,
Pat. Pending
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