PIC18f5440 usb lcd interface?

GizmoTheGreen · Post by **GizmoTheGreen** » March 21st, 2009, 9:42 pm

I just bought a PIC18F4550.

Anyone know how to make a simple, usb -> HD47780 interface?

I have good soldering skills, and some programming skills, but i have never done anything PIC before.

Post by **caesar** » March 22nd, 2009, 9:53 pm

It's really easy.
You can inspire yourself from ch242 source for 18F2550 and adapt it for your display.
Or I can dig after my sourcecode for the 4x40 display.

C18 Student Edition is available for free from Microchip.

GizmoTheGreen · Post by **GizmoTheGreen** » March 23rd, 2009, 9:17 am

thanks, any links for that source or c18 student edition?

i also have no idea about the chip pins and signals, do they need resistors, capacitors?

ive heard terms like pullup resistor but i have no idea what it means

Im also completely new to coding for pic's, ive only done c/c++ some console apps before.

Post by **caesar** » March 25th, 2009, 7:57 am

You can begin the journey here: http://www.microchip.com/
This is PIC18F4550's page: http://www.microchip.com/wwwproducts/De ... e=en010300
there you will find the datasheet and various application notes.

You will have to download the USB framework: http://www.microchip.com/stellent/idcpl ... e=en537044 and look inside for USB CDC example (USB COM port)

That example can be compiled with
C18 http://www.microchip.com/stellent/idcpl ... e=en010014
installed after first installing
MPLAB IDE http://www.microchip.com/stellent/idcpl ... t=SW007002

Have a good read and post back

GizmoTheGreen · Post by **GizmoTheGreen** » March 26th, 2009, 9:03 pm

can you use 4bit mode on a com port?
instead of 8bit on lpt.

coz i have a usb2com port lying around

Post by **caesar** » March 27th, 2009, 7:36 pm

com port has signals in the range of +12V/-12V, not usable.

GizmoTheGreen · Post by **GizmoTheGreen** » March 28th, 2009, 1:56 pm

not all do?
i think some has 5v, depending on the mobo

i think its been mentioned in forums when discussing those easy diy jdm programmers.

how about using resistors or 5v regulator? i have a 7805 lying around...

Post by **caesar** » March 29th, 2009, 10:43 pm

well, even with TTL levels there is still 1 big problem, the com port doesn't have IO, it's either input or output (3 inputs and 3 outputs / serial port if I remember correctly).

and you need at least 5 outputs to drive an lcd.

lucas_siglo21 · Post by **lucas_siglo21** » March 30th, 2009, 2:12 am

if you gant to connect a pic to a serial rs-232 use a MAX232, it converts the levels