OpenEuphoria

1. [Eu 3.1]How to send many files to Arduino via USB?

• Posted by DanM_anew Mar 24, 2014
• 2093 views

Hi all, I used to be here and contribute a little, not much, been away, not really back, not any more proficient coding than I was then, but I do need some help trying to be able to load a bunch of .mp3 files into a MP3/SDcard daughter board ("shield") on an Arduino Uno.

I have a VS1053 MP3 Codec + SD dboard to use with Arduino Uno, which can store .mp3 files on the SD card to play through the VS1053, but I'll be mounting the assembly in such a way that makes it too hard to remove the microSD card from it to routinely change its contents; so I'm looking for a way to command delete specific files and then add a directory full of new .mp3 via the USB link from my laptop.

The command delete might be easy, through the Arduino IDE and its serial monitor, and I should be able to easily enough reprise selecting a directory & working through it here on the computer side, but I know nothing about serial, nor if Euphoria can even access the USB port.

Don't think I saw anything here that was directly related, though I might have missed it, so any help would be appreciated.

Dan

3. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by DanM_anew Mar 25, 2014
• 1995 views

From some things I've seen here, it seems that perhaps I can just deal with the USB port as a system recognized Com port? I don't know if I can specify baud, parity, & checksum for USB that way, and I'd have to arrange some kind of handshaking with the Uno so it has time to deal with receiving & handling the data, but does that approach seem like it's reasonable??

And if so, does anyone have any suggestions about setting USB baud, parity, and creating checksum, or any examples?

5. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by DanM_anew Mar 25, 2014
• 1978 views

Thanks Fernando, I did see that thread, amongst a few others, so I'll be looking into Jacques' serial port library. And your code example in particular, too! I pretty much live and breathe by examples!

Is there anything anyone can tell me about handshaking, as I'm sure I'll have to have the Uno 'sketch' (their word for program) tell the computer to wait while it handles chunks of data from each file.

[edit] and what about "checksum", how to create/assert/check?

Dan

7. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by DanM_anew Mar 26, 2014
• 1936 views

Hi again Fernando,

Hmpff! Your example simply worked! A Uno program waiting for serial input actually received characters sent via USB from your serial example, turned an led appropriately on or off, and even sent programmed text response back & was displayed back here! I can't stand it when things WORK, it really confuses me, it's so unexpected!

Now let's see if I can figure out how to send large amounts of data, multiple files, & have them get stored & named on a SD card connected to the Arduino Uno, & how long that'll take me.

Your example is a life saver, a workable starting point, thank you!

9. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by Fernando Mar 29, 2014
• 1928 views

Hi Dan,

A simple approach is to sum all bytes of the data and take the least significant byte of this sum as the checksum. Then, it's common to 2-complement (to obtain the negative) that checksum and append it to the data. The receiver of the data, then, calculate its checksum and if it's different from zero, probably there was an error in the communication.

A more robust algorithm is the Fletcher's checksum (http://en.wikipedia.org/wiki/Fletcher%27s_checksum). It's a position dependent checksum.

Some possible implementations in Euphoria (3.1):

function Fletcher16(sequence data) 
integer sum1, sum2 
	sum1 = 0 
	sum2 = 0 
	for i = 1 to length(data) do 
		sum1 = remainder(sum1 + data[i], 255) 
		sum2 = remainder(sum2 + sum1, 255) 
	end for 
	return { sum2, sum1 } 
end function 

or

function Fletcher16(sequence data) 
integer sum1, sum2 
	sum1 = 0 
	sum2 = 0 
	for i = 1 to length(data) do 
		sum1 += data[i] 
		if sum1 >= 255 then sum1 -= 255 end if 
		sum2 += sum1 
	end for 
	sum2 = remainder(sum2,255) 
	return { sum2, sum1 } 
end function 

With the following function, you could take your data and append it with two bytes so that the Fletcher's checksum will be zero:

function AppendFletcher16(sequence data) 
sequence csum 
integer c0, c1 
	csum = Fletcher16(data) 
	c0 = 255 - remainder(csum[2] + csum[1],255) 
	c1 = 255 - remainder(csum[2] + c0,255) 
	return  data & c0 & c1 
end function 

Then the receiver computes the Fletcher's checksum and if it's different from zero, probably there was an error in the communication.

An even more robust approach is compute the CRC (cyclic redundancy code)(http://en.wikipedia.org/wiki/Cyclic_redundancy_check).

Here is one kind of a CRC-16 implementation:

constant TabCRCLo = 
	{ 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #01, #C0, #80, #41, 
	#00, #C1, #81, #40, #00, #C1, #81, #40, #01, #C0, 
	#80, #41, #01, #C0, #80, #41, #00, #C1, #81, #40, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #00, #C1, 
	#81, #40, #01, #C0, #80, #41, #01, #C0, #80, #41, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #00, #C1, 
	#81, #40, #00, #C1, #81, #40, #01, #C0, #80, #41, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #00, #C1, #81, #40, 
	#01, #C0, #80, #41, #01, #C0, #80, #41, #00, #C1, 
	#81, #40, #01, #C0, #80, #41, #00, #C1, #81, #40, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #00, #C1, #81, #40, 
	#01, #C0, #80, #41, #00, #C1, #81, #40, #01, #C0, 
	#80, #41, #01, #C0, #80, #41, #00, #C1, #81, #40, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #01, #C0, #80, #41, 
	#00, #C1, #81, #40, #00, #C1, #81, #40, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #01, #C0, #80, #41, 
	#01, #C0, #80, #41, #00, #C1, #81, #40, #01, #C0, 
	#80, #41, #00, #C1, #81, #40, #00, #C1, #81, #40, 
	#01, #C0, #80, #41, #01, #C0, #80, #41, #00, #C1, 
	#81, #40, #00, #C1, #81, #40, #01, #C0, #80, #41, 
	#00, #C1, #81, #40, #01, #C0, #80, #41, #01, #C0, 
	#80, #41, #00, #C1, #81, #40 
	} 
 
constant TabCRCHi = 
	{ 
	#00, #C0, #C1, #01, #C3, #03, #02, #C2, #C6, #06, 
	#07, #C7, #05, #C5, #C4, #04, #CC, #0C, #0D, #CD, 
	#0F, #CF, #CE, #0E, #0A, #CA, #CB, #0B, #C9, #09, 
	#08, #C8, #D8, #18, #19, #D9, #1B, #DB, #DA, #1A, 
	#1E, #DE, #DF, #1F, #DD, #1D, #1C, #DC, #14, #D4, 
	#D5, #15, #D7, #17, #16, #D6, #D2, #12, #13, #D3, 
	#11, #D1, #D0, #10, #F0, #30, #31, #F1, #33, #F3, 
	#F2, #32, #36, #F6, #F7, #37, #F5, #35, #34, #F4, 
	#3C, #FC, #FD, #3D, #FF, #3F, #3E, #FE, #FA, #3A, 
	#3B, #FB, #39, #F9, #F8, #38, #28, #E8, #E9, #29, 
	#EB, #2B, #2A, #EA, #EE, #2E, #2F, #EF, #2D, #ED, 
	#EC, #2C, #E4, #24, #25, #E5, #27, #E7, #E6, #26, 
	#22, #E2, #E3, #23, #E1, #21, #20, #E0, #A0, #60, 
	#61, #A1, #63, #A3, #A2, #62, #66, #A6, #A7, #67, 
	#A5, #65, #64, #A4, #6C, #AC, #AD, #6D, #AF, #6F, 
	#6E, #AE, #AA, #6A, #6B, #AB, #69, #A9, #A8, #68, 
	#78, #B8, #B9, #79, #BB, #7B, #7A, #BA, #BE, #7E, 
	#7F, #BF, #7D, #BD, #BC, #7C, #B4, #74, #75, #B5, 
	#77, #B7, #B6, #76, #72, #B2, #B3, #73, #B1, #71, 
	#70, #B0, #50, #90, #91, #51, #93, #53, #52, #92, 
	#96, #56, #57, #97, #55, #95, #94, #54, #9C, #5C, 
	#5D, #9D, #5F, #9F, #9E, #5E, #5A, #9A, #9B, #5B, 
	#99, #59, #58, #98, #88, #48, #49, #89, #4B, #8B, 
	#8A, #4A, #4E, #8E, #8F, #4F, #8D, #4D, #4C, #8C, 
	#44, #84, #85, #45, #87, #47, #46, #86, #82, #42, 
	#43, #83, #41, #81, #80, #40 
	} 
 
 
function CRC(sequence data) 
integer i, CRCHi, CRCLo 
	CRCHi = #00 
	CRCLo = #00 
	for j = 1 to length(data) do 
		i = xor_bits(CRCLo, data[j])								 
		i += 1															 
		CRCLo = xor_bits(CRCHi,TabCRCLo[i])						 
		CRCHi = TabCRCHi[i]											 
	end for 
	return { CRCLo, CRCHi }											 
end function 
 

- Fernando

11. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by ryanj Mar 30, 2014
• 1797 views

I don't know if this helps, but I designed a packet format for serial communication with the Propeller IC:

┌───────┐ 
│01(SOH)│ 
├───────┤ 
│DataLen│ 
├───────┤ 
│02(STX)│ 
├───────┤ 
│MsgType│ 
├───────┤ 
│MsgDat0│ 
│   :   │ 
│   :   │ 
│   :   │ 
│MsgDatX│ 
├───────┤ 
│03(ETX)│ 
├───────┤ 
│CRC16b0│ 
├───────┤ 
│CRC16b1│ 
├───────┤ 
│04(EOT)│ 
└───────┘ 

By setting up logic to look for the byte values in the right places, you can receive variable size packets and extract the data out of them. I haven't had the need to implement the CRC check yet, so it's just a place-holder.

13. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by ryanj Mar 30, 2014
• 1790 views

I looked at an ASCII chart and picked those particular ASCII codes, because i thought they made the most sense. Here is the Euphoria version for reading a packet, to get you started. It gets an unknown number of bytes for the serial port, and attempts to process it until enough bytes come in to make the complete packet. If it takes too long, it times out.

constant 
SOH = 1,  
STX = 2, 
ETX = 3, 
EOT = 4, 
MAXMSGLEN = 96 
 
procedure device_read_task() 
    atom Timeout, MsgLen, MsgCRC 
    sequence InBuffer = {}, MsgData 
    object inb 
     
    while 1 do 
        Timeout = time() 
        inb = usb:Read() --read bytes in buffer 
        if sequence(inb) and length(inb) > 0 then 
            Timeout = time() 
            InBuffer &= inb 
        end if 
     
        MsgData = {} 
        for b = 1 to length(InBuffer) do 
            if (length(InBuffer) - b + 1) > 7 then 
                if InBuffer[b] = SOH then 
                    MsgLen = InBuffer[b+1] 
                    if MsgLen <= MAXMSGLEN and InBuffer[b+2] = STX then 
                        if length(InBuffer) >= b + 7 + MsgLen - 1 then 
                            if InBuffer[b+3+MsgLen] = ETX and InBuffer[b+3+MsgLen+3] = EOT then 
                                MsgData = InBuffer[b+3..b+3+MsgLen-1] 
                                 
                                process_message(MsgData[1], MsgData[2..$]) --process packet data (msgtype, msgdata) 
                                 
                                InBuffer = {} 
                                exit 
                            end if 
                        end if 
                    end if 
                end if 
            end if 
        end for 
         
        if time() - Timeout > 0.5 then 
            InBuffer = {} 
        end if 
         
        task_yield() 
    end while 
end procedure 

15. Re: [Eu 3.1]How to send many files to Arduino via USB?

• Posted by ryanj Mar 30, 2014
• 1793 views

     while 1 do 
--     puts(1, "this is in the while to receive echo" & "\n") 
 
--read count bytes from serial port 
--global function serial_get_bytes(atom hCom, integer count) 
 
            val = {} 
     		val = serial_getc(hCom1)  -- AND THIS RECEIVES AND DISPLAYS ANY RESPONSE 
	        if val != -1 then 
	          val &= serial_get_bytes(hCom1,length(chunk)) -- SHOULD get whole echo 
              puts(1, "\nIT GOT AN ECHO!  " & val & "\n") 
              puts(1, "length of echo= " & sprint(length(val)) & "\n\n") 
	          exit 
            end if 
     end while 

It's good to use the same packet format both directions, whether sending large data or something as small as an acknowledgment message. If you use the first byte of the message to identify the message type, you can create a list of message type constants and handle the incoming packets easily with switch/case or if/then statements, and even handle errors and retries easily.