FEZ Panda and Picaso 4D Systems uVGA

NETMF & Gadgeteer
1

Hi,

I’m working on a simple thermoscan project. I’m using Devantech’s TPA81 thermal array sensor and two servos to scan an area for temperature changes.
Then all the data are sent through serial communication to a Picaso uVGA-II processor that “prints” an image
in any screen that has VGA output creating a “thermal” image.

The Picaso can be accessed through a simple serial TTL port.

Anyway, the first part was easy, using a FEZ Panda and two servos I get all the data through I2C.

The issue I have is with the Picaso. It accepts simple byte commands in two ways: either by sending a Hex
number or a character representing the command you want to use.
For example, by serially sending 0x55 or ‘U’ , you send the Autobaud command.

The problem lies in the code I use, by having C# understand what exactly I want to send.

I have made a small class to have all the commands in one place. I have debbuged The “Send” or “SendChar” function I use, and it seems to send the correct data, but nothing happens.

I have tried any available code I found on the Internet but it seems that the command is sent in the wrong way and also I can’t seem to read anything back ( like an ACK or NAK response sent by Picaso).
Below, you can see a part of the code I am using,

P.S. I also use the Picaso with an Arduino Mega using the same logic in my code and it works perfect!

What is that I make wrong in this code??

Thanks!

using System;
using System.IO;
using System.Text;
using System.IO.Ports;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;


namespace VGAClass
{
    public class Picaso
    {
        private static SerialPort UART;
        private byte Screen_res = 0;
        private byte Picaso_ACK = 0x06; //command received-acknowledged-executed
        private byte Picaso_NAK = 0X15; //command not recognized
        
         public Picaso(string Comport, int baudrate)
        {
            UART = new SerialPort(Comport, baudrate);
            UART.BaudRate = 9600;                                    //9600 default rate for Picaso intialization
            UART.DataBits = 8;
            UART.Parity = Parity.None;
            UART.ReadTimeout = 0;
            UART.WriteTimeout = 0;
            UART.Handshake = Handshake.None;
            UART.Open();
        }

       

        public void Send(byte data)     //send a command byte
        {
            byte[] buffer = new byte[data];
            UART.Write(buffer, 0, buffer.Length);
        }

        public void SendChar(char data) //send a char-like command
        {

            byte[] buff = new byte[data];
            UART.Write(buff, 0, buff.Length);
        }
2

You are using the data byte or character to determine the size of the buffer rather then putting the byte or char into a buffer of size 1.

public void Send(byte data)     //send a command byte
 {
     byte[] buffer = new byte[]{data};
     UART.Write(buffer, 0, buffer.Length);
  }
 
public void SendChar(char data) //send a char-like command
{
     byte[] buff = new byte[]{(byte)data};
     UART.Write(buff, 0, buff.Length);
}
3

so simple, but I was stuck!.

thank you!

Theo

4

Theodoros,

Your interface to the uVGA controller sounds exciting.

Do you have a feeling for how fast this device is, and how viable it is as a VGA interface for FEZ?

Also, could you please post your driver once it is completed?

Thank you.

5

The Picaso is fast, really fast!
It has its own graphics processor that does the heavy work, an SD card interface and some available digital IOs to play with and a simple TTL interface…And in the price of $55, it’s a bargain…

But it also depends on the other side too, the microcontroller you use to connect with.

I have used Arduino Mega for the thermoscan project and although the software part was easy, poor Arduino
was having a hard time driving two servos, getting data from TPA81 and send them to Picaso.

FEZ Panda on the other side is an ARM and there is a lot of power to drive this fast enough.

You can use any VGA monitor with Picaso but since I wanted this to be “portable” I purchased this from eBay:

[url]http://www.ebay.com/itm/7-TFT-LED-LCD-Module-A-D-Board-VGA-2AV-Function-/190571437289?pt=BI_Electrical_Equipment_Tools&hash=item2c5ef15ce9[/url]

It’s a 7" TFT LCD screen with a VGA connection and works great! I already have it connected to Picaso and
draw some lines and rectangles using Panda.

I believe that the potentials from Panda+Picaso are limitless…

I will post my code in tinyCLR code page soon enough.

Theo

6

Thank you. I’m really looking forward to seeing the results of your project.