Nope, I do not mean the PIC. What I mean is the FLASH MEMORY, a single chip such as the model AMD28F26. I just wish to know whether I can generate the timing using the PIC as I know that in order to execute the write or read operation to the flash memory chip, I need a lot of timing. And I know the by calling the delay in the PIC, I can have the timing I wish to have.

Do U think this is possible to be done with the help of the PIC? Thanks Nigel!

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your helps will be much appreciated!

 

Certainly generating fairly accurate timing is quite easy with a PIC, so that shouldn't cause any problems. The main problems are likely to be the format that the FLASH memory uses, unless you are using your own formatting? - often FLASH memories are formatted in a simlar way to a disk drive, and a PIC doesn't really have enough RAM to deal with it.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Another way could be, use a larger pic. Have it write to its own Flash, or EEPROM.
Or use an external flash with a SPI or I2C interface.

Why do you want to use this type of external flash?
What are your needs?

Kent

ps. I just found a data sheet for a Am28F256, and the interface is quite complex, it looks like it needs 15 address lines and 8 data lines.
I have never used one of these, so I don't know the correct interface.
But my thought is that a serial interface would be easer, most Pics have them built in.

Some day I need to reprogram a simular chip for the CMOS in a older PC. I might know more then.

Please let Us know more details......

 

Hi, is me again. This time, I attached the schematic of my prject which I design myself. Can U look at it and tell me is it ok?

Here are some of the things needed to be taken note in the schematic:-
1. D0, D1 is command bit, when D0=0, D1=1 then on/off device will try
to operate the PIC to the on off device subroutine. If D0=1,D1=0,
then subroutine to change group address will be call. (This address will
be checked everytime before any operation is carried out. It is carried
in D2, D3, D4 which are connected to RA2, RA3 and RA4 respectively.)

2. D5, D6 and D7 connected to RB0, RB1, RB2 respectively. These 3 bits
will carry the device ID which indicate which device is switched on.
However, when the operation has change to change address (which
indicate by D0(RA0)=1, D1(RA1)=0), these 3 bits will store the new
address to overwrite the old group address.

3. RB3 is the output pins that I use to trigger on the demultiplexer
(74AC11138) and also the feeback encoder when the on/off subroutine
is called.

4. RB4 is the output pin that I use to trigger on the feeback encoder when
change address subroutine is called.

5. RB5 , 6, and 7 are unused pins.

6. I use the OSC2 pin of PIC and connect a resistor(330K) parallel with
capacitor (220nF) for oscillation function. Is this a need? :?:

-------------------------
My concern..sorry oh..
1. Does my connection ok?
2. Do I need to connect a resistor to every input pin in order to protect
the PIC?
3. OSC1 need to connect?
4. OSC2 need to connect?
5. The MCLR connected to high always right?

------------
My PIC Program , I will upload it in the next post reply. And Also my question is I already test the program with MPLAB and it shows OK, NO ERROR. Hwoever I cant get the output. Can U just have a look on my program.?

Is there any software that we can simulate the PIC on the computer screeen itself/?
Thanks, Hope my question is not making U feel angry..Thans very much!

Attached Images

schematic_105.jpg (119.0 KB, 441 views)

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your helps will be much appreciated!

 

This is my PIC Program MOdel of PIC is PIC16F84.

Can u explain to me inside ur SONY program, there is one line "goto $-1"
what is that for?
THanks A LOTS!!! ops:

Attached Files

pic.txt (4.3 KB, 32 views)

__________________
your helps will be much appreciated!

 

$ is an assembler directive, it's explained in the MPASM help file.

Basically $ is the current address, so "goto $-1" means jump back one line, it's a convenient way of doing a small jump without the complications of labels.

As for your oscillator query, the 16F84 requires a resistor and capacitor for an RC oscillator - if you replace the obselete 84 with it's replacement, the 16F628, it has a fully internal 4MHz oscillator - this gives you 16 I/O pins, and is cheaper than the old 84.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Thansk Nigel. By the way, can u spend some time on my schematic diagram and try to give me some opinion on my questions? Sorry, ops: ops: ops: Thansk a lots.........I have no choice but to use the PIC16F84 because I have bought it. For my case, the timing issue will be a problem? Thanks...

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your helps will be much appreciated!

 

I'm rather confused as to what all the chips are doing?, it seems pointless using the Holtek chips when the PIC can quite easily perform the functions of both?. If you look at my remote control tutorials I transmitt and receive Sony SIRC remote control signals, it would be trivial to modify those routines to do what you want.

No.

Yes, as I remember it's the RC oscillator pin.

No, unless I remembered wrong, and this is the RC oscillator pin.

Yes.

You seem to have concerns over timing accuracies, if so you should be using a XTAL oscillator - the external RC oscillator is the most inaccurate you could possibly use!. On the 16F84 you don't lose anything by using a crystal, unlike the 628 the OSC pins are fixed and can't be used as I/O.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

Go to microchip and get a sample of the chip you need. Then buy more the next time.

Kent

 

In PIC16F84, What is the difference of using a subroutine to perform an operation and using an interrupt to perform an operation. In this case, I need to perform an operation only when certain inputs receive data.

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your helps will be much appreciated!

 

I usualy use a MAIN_LOOP, that checks trigger regs for change, and goes and does the needed function, then returns, for the next function.

What is the trigger going to be?
Port change?
Register change?

Kent

 

How to generate an accurate 1 second delay in the PIC16F84..? Thanks

__________________
your helps will be much appreciated!

 

Use the delay code generator on the PICList, just enter your clock speed, delay required, and press the button - instant accurate delay code!.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk

 

If during the first time program, I wish to store some data into the EEPROM of PIC. (means that I need to have data inside my EEPROM of PIC before I load my main program into the PIC) This data inside the EEPROM is to be compared with the inputs from the port.

Therefore, when I program at the first time and then the second time, is it I need to 'click' the "code protected" to ensure my data in the EEPROM is not deleted when I program it second time? Thanks

fainted....

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your helps will be much appreciated!

 

NO! - code protection is to prevent anyone reading the code out of the chip. The first thing programming the chip does is wipe it completely, and remove the code protection.

If you want to keep any modified data from the EEPROM, you need to read the chip and incorporate the EEPROM data in the source code.

__________________
PIC programmer software, and PIC Tutorials at:
http://www.winpicprog.co.uk