Pic12F683 LCD question

lurkepus · Nov 2, 2011

Hi
I'm new to using/programming MCU's and i have started with the pic12F683.

I also use assembly to programm the pic since i found the syntax for coding to be easy comapred to C.

The problem i got is to connect he 683 to a hc595 shift register and then to a HD44780 16X2 LCD display. I have been searching for an asembler demo for this setup but so far i have just found a page where the code is in C .

I have managed to connect the 683 to the shiftregister but the problem is that i can just send one bit at the time but to be able to use the LCD i need to be transfereing stuff like 0x20 (LED wakeup sequence) and other simmilar code.

My question is .. Does anyone have an example asm file or a link to a page witch have some code i can learn from .

DerStrom8 · Nov 2, 2011

lurkepus said:
Hi
I'm new to using/programming MCU's and i have started with the pic12F683.

I also use assembly to programm the pic since i found the syntax for coding to be easy comapred to C.

The problem i got is to connect he 683 to a hc595 shift register and then to a HD44780 16X2 LCD display. I have been searching for an asembler demo for this setup but so far i have just found a page where the code is in C .

I have managed to connect the 683 to the shiftregister but the problem is that i can just send one bit at the time but to be able to use the LCD i need to be transfereing stuff like 0x20 (LED wakeup sequence) and other simmilar code.

My question is .. Does anyone have an example asm file or a link to a page witch have some code i can learn from .

If it is an ASM tutorial you're looking for, I have found **broken link removed** to be very helpful.

Good luck!
Der Strom

lurkepus · Nov 2, 2011

Thanks for the link , I have used that site myself but i haven't found the solution to the problem with the hc595. This page has what i need but the code is in C maybe someone can "translate" it to assembler or maybe post a link to a simmilar page with code written in assembly

lurkepus · Nov 2, 2011

sorry forgot the link https://embedded-lab.com/blog/?p=30

DerStrom8 · Nov 2, 2011

lurkepus said:
sorry forgot the link https://embedded-lab.com/blog/?p=30

Unfortunately, just translating C to ASM isn't all that easy. Parts of the program will depend entirely on the chip the original program was designed for, and the chip that is going to be programmed with ASM. It would be difficult for someone who has not used these particular chips to translate.

What you need is a compiler. When you write in C, it usually translates it to ASM when it's compiled, before programming the chip. By putting the C into a compiler, it will translate it to ASM. Keep in mind you may have to make several changes in order to make it work with your chip.

Try using google to find the right compiler.

Good luck!
Der Strom

Wp100 · Nov 2, 2011

Hi,

You might find these sites usefull.

Have to ask why you have to use an extra 74 chip rather than getting a Pic with more pins ?

http://www.rentron.com/Myke1.htm

http://jap.hu/electronic/lcdif.html

DerStrom8 · Nov 2, 2011

You may be able to run the code in MPLAB and have it translate it to ASM for you. I haven't done this myself, so I'm not sure if you can do that or not. Definitely worth a try, though.

lurkepus · Nov 2, 2011

the C code on that page i linked to is the same as i use so if i could use MPLAB to convert it it should be ready to use ?

lurkepus · Nov 2, 2011

Wp100 said:
Hi,

You might find these sites usefull.

Have to ask why you have to use an extra 74 chip rather than getting a Pic with more pins ?

http://www.rentron.com/Myke1.htm

http://jap.hu/electronic/lcdif.html

i did choose the 683 due to the cost and the features it have .. I got the 683 just to learn more about mcu's .

The reason for the 74 chip was that i came across the page i mentioned and i wanted to see if i could get it to work , witch i'm sure i will if someone points me in the right direction

Ian Rogers · Nov 2, 2011

I have this code running on a pic12f675.. it was coded in basic... I will send you the assembled file
It uses a 74HC174 as a shift register

The basic file AND the asm file is attached (the asm file has no comments so it may be a little daunting)

Mike - K8LH · Nov 2, 2011

How are you hooking up the 74HC595 and LCD? Same as the schematic on the embedded-lab.com page?

lurkepus · Nov 2, 2011

Ian Rogers said:
I have this code running on a pic12f675.. it was coded in basic... I will send you the assembled file
It uses a 74HC174 as a shift register

The basic file AND the asm file is attached (the asm file has no comments so it may be a little daunting)

Thanks i will take a look at the file

Mike said:
How are you hooking up the 74HC595 and LCD? Same as the schematic on the embedded-lab.com page?

Right now i just got som LED's hooked up to the Hc595 but the pic and the 595 are connected the same way as on that page

Wp100 · Nov 2, 2011

Hi,

Just tested out that 2 wire link for the 16F84 -it works ok, so have just quicky modified the ports and tried it on the 12F683 and again it seem to work fine in simulation.

lurkepus · Nov 2, 2011

Wp100 said:
Hi,

Just tested out that 2 wire link for the 16F84 -it works ok, so have just quicky modified the ports and tried it on the 12F683 and again it seem to work fine in simulation.

Thanks I will give it a try however on the page i linked to they used 2 wires connected to the 595 and one connected to the LCD (data/command) anyway i can try both of em

lurkepus · Nov 2, 2011

btw this is the actual setup i will be using the only problem was the fact that the code was in C https://embedded-lab.com/blog/?p=30

Mike - K8LH · Nov 2, 2011

lurkepus said:
btw this is the actual setup i will be using the only problem was the fact that the code was in C https://embedded-lab.com/blog/?p=30

Yeah, that's the one I was looking at... Let's see what we can do...

lurkepus · Nov 3, 2011

lurkepus said:
Thanks I will give it a try however on the page i linked to they used 2 wires connected to the 595 and one connected to the LCD (data/command) anyway i can try both of em

I tried the code (LED instead of the LCD) but i got no output to the LED's. only thing i changed in the code was the ports (to GPIO 1 and 2 ).

Only result i got was a brief blink of all 8 leds when i powerd up the 683.. maybe the code isn't compatible with the 595 chip ?

DerStrom8 · Nov 3, 2011

Post removed

DerStrom8 · Nov 3, 2011

lurkepus said:
I tried the code (LED instead of the LCD) but i got no output to the LED's. only thing i changed in the code was the ports (to GPIO 1 and 2 ).

Only result i got was a brief blink of all 8 leds when i powerd up the 683.. maybe the code isn't compatible with the 595 chip ?

It sounds like you didn't put it in a loop. It executes it once, but then stops. Did you write the program in ASM, or did you use the C file? It may also be the watchdog timer--I've had a few issues with that before, too

lurkepus · Nov 3, 2011

it's the lcd_2wire.asm that you will find close to the top of this page ... it was orignaly made for a different pic ,shiftregister and LCD ...

Pic12F683 LCD question

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