What is the math task and which LCD?

Reading the NMEA data is very fast and easy, the math task (and the code to drive the LCD) are the things that will decide the amount of memory you need.

Like a lot of OP's you want us to suggest a solution when you have not yet provided enough information.

I don't know what OP's means, but I am an OAP.

I am limited in my computing skills, sorry.

I am trying to choose a PIC chip, and in my last post, I suggested a few.

I am hoping that someone, who is experienced, could guess, the size of the code for me from past experiences of calculating this sort of thing.

I'm guessing that 8K will be enough.

 

16F processors certainly can work with external RAM, though they aren't designed for it. And I wonder if the awkward interface you end up with would slow the program down to the point where it just wouldn't be workable.

But yes, write the program first and compile it, and see how much ROM and RAM the compiler thinks you need. Try it for different processors and you can get an idea of which one you're likely to need.

 

Can you explain a bit more about using external RAM please. I assume this is where the code goes?

No, this would be where variables go, if you find that you run out of RAM. The program code is still internal to the controller.

You haven't given us information as to what it is you're doing, so we are unsure of what you actually will need...

Edit: OP can mean either Original Post, or Original Poster, depending on context...

 

I don't know what OP's means, but I am an OAP.

I am limited in my computing skills, sorry.

I am trying to choose a PIC chip, and in my last post, I suggested a few.

I am hoping that someone, who is experienced, could guess, the size of the code for me from past experiences of calculating this sort of thing.

I'm guessing that 8K will be enough.

Are you talking abot 8KB or 8KW ( PIC16Fxx have 14bit instruction word )
Anyway 16F619 has 8KW ( ~14KB ) program space and is supported by Oshonsoft.
Last version 6.99 has a couple of demos in Basic.
I changed one a little: it writes to 2*16 LCD, does floating point add, multiply and sine + cosine functions and takes 2600 program words.

Why don't you just write the code, compile it and look if it fits your controller

 

JohnP, Tshuck, and Jjw and all,

I've been reading up, and there are many different terms for memory, that are confusing, but I think I have some idea now.

I am not skilled enough to write the program, but I'll find a similar one written in 'C' and try to convert it.

First I'm going to understand LCD readouts, and will look at the V6.99.

The end result will be an antenna tracker that follows the NMEA data source. This is why I don't know about the equation, as it's completely beyond me.

I'll do so simulations and slowly build up LCD, then NMEA data by then I might have some idea about the maths.

Thanks for you input, Camerart.

 

I don't understand the term 'generic', but I did find reference to 4 bit, which used 2X flipflops, is this what you mean?

"There are many reasons why sometime we prefer to use LCD in 4-bit mode instead of 8-bit. One basic reason is lesser number of pins are needed to interface LCD."
http://www.8051projects.net/lcd-interfacing/lcd-4-bit.php

 

"There are many reasons why sometime we prefer to use LCD in 4-bit mode instead of 8-bit. One basic reason is lesser number of pins are needed to interface LCD."
http://www.8051projects.net/lcd-interfacing/lcd-4-bit.php

I had a quick look and I notice it's in 'C' so I'll have to find someone to help me decode it, but thanks for the link it looks interesting.

 

I had a quick look and I notice it's in 'C' so I'll have to find someone to help me decode it, but thanks for the link it looks interesting.

Now that I had time to think on it. It is kind of mixed bag. On one hand, you use fewer pins, 4 for data, 2 for control, total of 6 pins. On the other hand, there is more code since you need to split the 8 bits into 4 bits before you send them to lcd.

This next page has both, assembly and C: http://www.8051projects.net/lcd-interfacing/lcd-4-bit-programming.php

 

I had a quick look and I notice it's in 'C' so I'll have to find someone to help me decode it, but thanks for the link it looks interesting.

Oshonsoft Basic has a function for interfacing LCD.
You just have to define which pins to use, 4bit / 8bit interface etc.

 

Oshonsoft Basic has a function for interfacing LCD.
You just have to define which pins to use, 4bit / 8bit interface etc.

I'll have to weigh up the differences, and choose!

The three chips I posted have the LCD facility, which makes the choice easier.

I assume, that when writing a program in Oshonsoft, there is a kind of count that will let me know if the chip memory is getting full, so i'll start writing, and change chip if needed.

Thanks, Camerart.

 

It's not a trivial project. I do multi-axis motion control stuff regularly and it would still be a lot of work for someone with my skill. And it sounds like you have never written code and know practically nothing about the PIC chips either (that's not an insult sorry, just an observation).

Have you considered teaming up with somone who has the other skills, ie good with code, good with real time motion control, good with PICs?

I'm too busy but others here might find it an interesting project.

 

I'll have to weigh up the differences, and choose!

The three chips I posted have the LCD facility, which makes the choice easier.

I assume, that when writing a program in Oshonsoft, there is a kind of count that will let me know if the chip memory is getting full, so i'll start writing, and change chip if needed.

Thanks, Camerart.

The LCD facility you mentioned is for the so called "LCD glass"
Each segment of the display is driven separately so a lot of IO pin
Is needed.
I think it is easier to use some standard LCD eg. 2*20

 

The LCD facility you mentioned is for the so called "LCD glass"
Each segment of the display is driven separately so a lot of IO pin
Is needed.
I think it is easier to use some standard LCD eg. 2*20

I have 4X20 LCDs, I was unaware about 'LCD glass'

 

It's not a trivial project. I do multi-axis motion control stuff regularly and it would still be a lot of work for someone with my skill. And it sounds like you have never written code and know practically nothing about the PIC chips either (that's not an insult sorry, just an observation).

Have you considered teaming up with somone who has the other skills, ie good with code, good with real time motion control, good with PICs?

I'm too busy but others here might find it an interesting project.

I have written lots of smaller programs, for driving camera cars, and photography developing machinery etc, in Basic. Hopefully, I'll probably get there eventually in basic.

My way of teaming up with someone with programming skill, is to come on forums, but I firstly wanted to know about choosing chips, and thanks to the forum, I now can.

I tried a thread 'GPS NMEA antenna aiming tracker.' but after lots of lookers, received no replies, so perhaps it's more daunting for others

Sorry your too busy, but thanks,

Camerart.

 

I have made progress, but I will post it in 'GPS NMEA antenna aiming tracker.'

Thanks to everyone who helped me choose a PIC. I consider this thread closed.

Cheers, Camerart.