new to javelin

darnit · 2006-04-17 19:57

OK.......I have decided to 'byte' the bullet and move into the world of JAVELIN stamps.· I have been through the manual a couple of times and I am beginning to get the idea of what is going on.· I have come to the conclusion that what i need to do is just dive in.· With that in mind I have decided to try and move my current project of interfacing to a CrystalFontz 635 LCD to a JAVELIN stamp.· Since this part has given me the biggest headache I am going to ask for help up front.· following is some sample JAVA code for calculating CRC using a lookup table.· The problem seems to be that it works well in a 32 bit enviornment but not at all in the javeline IDE.· Can someone help me convert this over so I can use it to get started?

public class CRC16 extends Object
{
public static void main(String[noparse]/noparse args)
{
byte[noparse]/noparse data = new byte[noparse][[/noparse]2];
// hw - fw
data[noparse][[/noparse]0] = 0x01;
data[noparse][[/noparse]1] = 0x00;
System.out.println("hw -fw req");
System.out.println(Integer.toHexString(compute(data)));
// ping
data[noparse][[/noparse]0] = 0x00;
data[noparse][[/noparse]1] = 0x00;
System.out.println("ping");
System.out.println(Integer.toHexString(compute(data)));
// reboot
data[noparse][[/noparse]0] = 0x05;
data[noparse][[/noparse]1] = 0x00;
System.out.println("reboot");
System.out.println(Integer.toHexString(compute(data)));
// clear lcd
data[noparse][[/noparse]0] = 0x06;
data[noparse][[/noparse]1] = 0x00;
System.out.println("clear lcd");
System.out.println(Integer.toHexString(compute(data)));
// set line 1
data = new byte[noparse][[/noparse]18];
data[noparse][[/noparse]0] = 0x07;
data[noparse][[/noparse]1] = 0x10;
String text = "Test Test Test ";
byte[noparse]/noparse textByte = text.getBytes();
for (int i=0; i < text.length(); i++) data[noparse][[/noparse]i+2] = textByte[noparse][[/noparse]i];
System.out.println("text 1");
System.out.println(Integer.toHexString(compute(data)));
}
private CRC16()
{
}
private static final int[noparse]/noparse crcLookupTable =
{
0x00000,0x01189,0x02312,0x0329B,0x04624,0x057AD,0x06536,0x074BF,
0x08C48,0x09DC1,0x0AF5A,0x0BED3,0x0CA6C,0x0DBE5,0x0E97E,0x0F8F7,
0x01081,0x00108,0x03393,0x0221A,0x056A5,0x0472C,0x075B7,0x0643E,
0x09CC9,0x08D40,0x0BFDB,0x0AE52,0x0DAED,0x0CB64,0x0F9FF,0x0E876,
0x02102,0x0308B,0x00210,0x01399,0x06726,0x076AF,0x04434,0x055BD,
0x0AD4A,0x0BCC3,0x08E58,0x09FD1,0x0EB6E,0x0FAE7,0x0C87C,0x0D9F5,
0x03183,0x0200A,0x01291,0x00318,0x077A7,0x0662E,0x054B5,0x0453C,
0x0BDCB,0x0AC42,0x09ED9,0x08F50,0x0FBEF,0x0EA66,0x0D8FD,0x0C974,
0x04204,0x0538D,0x06116,0x0709F,0x00420,0x015A9,0x02732,0x036BB,
0x0CE4C,0x0DFC5,0x0ED5E,0x0FCD7,0x08868,0x099E1,0x0AB7A,0x0BAF3,
0x05285,0x0430C,0x07197,0x0601E,0x014A1,0x00528,0x037B3,0x0263A,
0x0DECD,0x0CF44,0x0FDDF,0x0EC56,0x098E9,0x08960,0x0BBFB,0x0AA72,
0x06306,0x0728F,0x04014,0x0519D,0x02522,0x034AB,0x00630,0x017B9,
0x0EF4E,0x0FEC7,0x0CC5C,0x0DDD5,0x0A96A,0x0B8E3,0x08A78,0x09BF1,
0x07387,0x0620E,0x05095,0x0411C,0x035A3,0x0242A,0x016B1,0x00738,
0x0FFCF,0x0EE46,0x0DCDD,0x0CD54,0x0B9EB,0x0A862,0x09AF9,0x08B70,
0x08408,0x09581,0x0A71A,0x0B693,0x0C22C,0x0D3A5,0x0E13E,0x0F0B7,
0x00840,0x019C9,0x02B52,0x03ADB,0x04E64,0x05FED,0x06D76,0x07CFF,
0x09489,0x08500,0x0B79B,0x0A612,0x0D2AD,0x0C324,0x0F1BF,0x0E036,
0x018C1,0x00948,0x03BD3,0x02A5A,0x05EE5,0x04F6C,0x07DF7,0x06C7E,
0x0A50A,0x0B483,0x08618,0x09791,0x0E32E,0x0F2A7,0x0C03C,0x0D1B5,
0x02942,0x038CB,0x00A50,0x01BD9,0x06F66,0x07EEF,0x04C74,0x05DFD,
0x0B58B,0x0A402,0x09699,0x08710,0x0F3AF,0x0E226,0x0D0BD,0x0C134,
0x039C3,0x0284A,0x01AD1,0x00B58,0x07FE7,0x06E6E,0x05CF5,0x04D7C,
0x0C60C,0x0D785,0x0E51E,0x0F497,0x08028,0x091A1,0x0A33A,0x0B2B3,
0x04A44,0x05BCD,0x06956,0x078DF,0x00C60,0x01DE9,0x02F72,0x03EFB,
0x0D68D,0x0C704,0x0F59F,0x0E416,0x090A9,0x08120,0x0B3BB,0x0A232,
0x05AC5,0x04B4C,0x079D7,0x0685E,0x01CE1,0x00D68,0x03FF3,0x02E7A,
0x0E70E,0x0F687,0x0C41C,0x0D595,0x0A12A,0x0B0A3,0x08238,0x093B1,
0x06B46,0x07ACF,0x04854,0x059DD,0x02D62,0x03CEB,0x00E70,0x01FF9,
0x0F78F,0x0E606,0x0D49D,0x0C514,0x0B1AB,0x0A022,0x092B9,0x08330,
0x07BC7,0x06A4E,0x058D5,0x0495C,0x03DE3,0x02C6A,0x01EF1,0x00F78
};
public static int compute(byte[noparse]/noparse data)
{
int newCrc = 0x0FFFF;
for (int i = 0; i < data.length; i++ )
{
int lookup = crcLookupTable[noparse][[/noparse](newCrc ^ data[noparse][[/noparse]i]) & 0xFF];
newCrc = (newCrc >> 8) ^ lookup;
}
return(~newCrc);
}
}

Peter Verkaik · 2006-04-17 23:50

I updated your code to comply with javelin compiler and linker.
Constant integer values >= 0x8000 must be casted to short,
otherwise the linker complains (the compiler complains not and
the linker is not involded until programming).

To print hex values, the Format class is your best option.
Download the Format class from here:
http://groups.yahoo.com/group/JavelinCode/files/Javelin%20Stamp%20IDE/lib/stamp/util/text/

Commandline arguments are not available to the javelin,
hence main is defined as static void main().

Parsing strings is done with charAt() which returns a char, not a byte,
so I changed compute(byte[noparse]/noparse) to compute(char[noparse]/noparse) so no casting is required.

Since the javelin has no garbage collection, do not use the keyword new
inside methods (unless you save references in global variables). Instead define global arrays.

Use >>> to shift right which is an unsigned shift.
>> is a signed shift (b15 is copied to b14,b13 etc)

regards peter

darnit · 2006-04-18 00:59

Peter,

Thank you for saving me a week or two or three......or five!· It will take me some time to understand what you did, so i am truly appreciative that you included an explanation.· I have only been working with the Javelin for a day and i really like it.·

Thanks again.

new to javelin

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