Develop Reference

FIDO2 - Get Authenticator Info issue

I am developing Android authenticator.I am getting {-125,0,1,4} byte array from webauthn client after pairing. When I decoding this array
-125 (0x83) - MSG
1 (0x01) - length of the data
4 (0x04) - AuthenticatorGetInfo
I am not sure about 0 in this array. Please let me know is there any meaning for this 0.
For this request, I am sending response as CBOR data.
00a60182684649444f5f325f30665532465f563202816b686d61632d73656372657403506435323965353235383533343133663304a462726bf5627570f564706c6174f469636c69656e7450696ef505190400069f01ff
I am notifying above data by using Fido Status as follows.
for (byte[] frame : response.toFrames(mMTU)) {
getFidoStatus().setValue(frame);
mGattServer.notifyCharacteristicChanged(device, getFidoStatus(), true);
}
After that I am not getting any request/response from webauthn client. I am sending KEEPALIVE(0x82) command with value PROCESSING(0x01) for every kKeepAliveMillis(500ms). Is there any issue with my implementation?
Please help me to proceed this. Thanks in advance.

This speciciation fully explains for you
https://fidoalliance.org/specs/fido-v2.0-id-20180227/fido-client-to-authenticator-protocol-v2.0-id-20180227.html#ble-framing-fragmentation
CMD is 0x83 (MSG)
Length of DATA is 2 bytes: HLEN byte and LLEN byte.
In your case, length of DATA is 0x0001 (= 1). The DATA is 0x04

Pic16F688 has no stable readings via buletooth

I have spent much time trying to find out where is my mistakes while Im flashing the PIC16F688. The Pic has successfully flashed using PicKit2. Im using the Pic to convert analog pressure sensor to digital output and sending the data via Bluetooth, but the Bluetooth is not receiving stable numbers of data. The data is consist of 4 character decimal number that is between 0 and 1023.
The problem is that the Bluetooth can't wait at specific number and keep reading it, instead, it is reading the 4 digits in random.
I think my mistake is within the configuration of internal oscillator.
I'm attaching my code, the code is written to configure the flexiforce sensor circuit that outputs analog voltage up to 5v, and then the pic duty is to convert it to digital as I mentioned above.
it might be my wiring is not correct, please If you could help out with this one
and what configuration "at edit project" do I need to choose for Mikro PRO software?
I used "Bluetooth terminal" app to see my data asynchronous from Bluetooth.
Thank you.
char *temp = "0000";
unsigned int adc_value;
char uart_rd; int i;
void main()
{
OSCCON = 0x77;
ANSEL = 0b00000100;
CMCON0 = 0X07;
TRISA = 0b00001100;
UART1_Init(9600);
Delay_ms(100);
while (1)
{
adc_value = ADC_Read(2);
temp[0] = adc_value/1000+48;
temp[1] = (adc_value/100)%10+48;
temp[2] = (adc_value/10)%10+48;
temp[3] = adc_value%10+48;
for (i=0;i<4; i++)
UART1_Write(temp[i]);
UART1_Write(13);
Delay_ms(1000);
}
}

You can use itoa function to convert ADC integer value to characters for sending over UART. If there is error in calculation then you wont get appropriate value. Below code snippet for your reference :
while (1)
{
adc_value = ADC_Read(2);
itoa(adc_value, temp, 10);
for (i=0;i<4; i++)
UART1_Write(temp[i]);
UART1_Write(13);
Delay_ms(1000);
}
Please check Baud Rate you have configured at both ends is same or not. If baudrate mismatches then you will get Random value at Bluetooth Terminal where you are reading values.

What i would suggest, if you have a logic analyser, hook it up. If you don't recalculate your oscillator speed with the datasheet. It could just be that the internal oscillator is not accurate enough. What also works, is to write a function in assembly that waits a known time (by copy-pasting a lot of NOPs and using this to blink a led. Then start a stopwatch and count, say, 100 blinks. This is what i used to do before i had a logic analyser. (They are quite cheep on ebay).

What's meaning of range start=range end in http response

When I try to analyse CDN download, some logs looks like below:
GET http://1234.apk?track=mmmmmmm range:bytes-sent=[500-500], content-length:1500 ...
In my understanding, range:bytes-sent represents continue download after break and it should have different number in bytes-sent, the followings are reasonable:
bytes-sent=[500-600]
bytes-sent=[500-]
bytes-sent=[-500]
but what meaning of range start = range end like [500-500]? It seems no data should be downloaded but generates http response.
Thanks first~

The bytes mentioned in the range are also sent. Hence if the server wants to only send the 500th byte, the server would send [500-500] as the bytes range. Have a look at https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-p5-range-26 which has an example of how the first and last byte are sent :
o The first and last bytes only (bytes 0 and 9999):
bytes=0-0,-1

HttpURLConnection readLine() hanging on Sprint 4G network

I have a routine that uses a HttpURLConnection to upload a file via a multipart/form-data content type. The server does some processing on the uploaded file and returns a short response code. This works fine in all cases so far except with one user with an HTC Evo when on 4G. If the user switches to 3G then everything works fine. When on 4G the app will wait on the while ((line = reader.readLine()) != null) { until a socket connection timeout exception is thrown. I have the connection timeout set to 70 seconds. The server is in php here is the relevant snippet
//all ob_ related entries were added because I found some info indicating
//that some clients would not acknowledge the response without the content-length header
ob_end_clean();
header("Connection: close");
ob_start();
...
//the response is one of either
echo "BACKGROUND"; //this one works!
//or
echo $rv //$rv = "1336757671374T37171FR"
//or
echo "FailedQA";
$size = ob_get_length();
header("Content-Length: $size");
ob_end_flush();
ob_flush();
flush();
die();
?>
Note that the 'BACKGROUND' response works, and the rest cause the client to sit until the timeout exception. I have currently 2 notions on this, but I am not in a 4G area so I can only test this through the end user and I really want to limit the number of attempts. My first thought is that the 'BACKGROUND' is slightly longer than the 'FailedQA', and while the other one is longer it has a numeric start. So maybe adding white space to the response would help? The other aspect is response time. The 'BACKGROUND' message is normally sent faster than the other ones. But, I do have a counter example here so I am not sire. Example: the 'BACKGROUND' message normally goes out within 15 to 20 seconds. The other messages are normally 30-40 seconds. However, I have one example where the '1336757671374T37171FR' style response went out in 24 seconds and was not received and one where the 'BACKGROUND' message went out in 27 seconds and was received.
So to sum up: This only happens on Sprint 4G. I suspect it might either be content length or response time that is causing the issue, but in both cases I have a counter example to the contrary. Except with the length case the one that is the longer counter example has a numeric beginning, so there's that.

It seems to be the delay before a response that was causing the problem. I used this guide Easy Parallel Processing in PHP to set up a multi-tasking php configuration. This way I have a script that just counts and echos the elapsed seconds while the other one does the job processing. The problem is now resolved.

get SensorValues from Arduino ADK

I'am working with arduino and ADK und I have problems to get Information from Arduino-Sensors. At the moment I can send Information from Phone to control LED or servos.... . But it is impossible for me to send Data via acc.write(msg,3) to smarthphone. I'am using this example Dev-O-Rama and try to extend this example to get sensor data(without success). To get sensordata I'am using code from ADK example. Everytime when I try to send data from arduino with: acc.write(msg,3) it seems everything freezing. Have someone a working "little" example or a hint what can cause this behavior?
LG Marcel

I figure it's the Android application that's freezing?
Try using the USBControl library in my project
The arduino write code is very simple:
//Batt update, 0.1 Hz loop
if (acc.isConnected() && millis()-timer_batt >= 1000/BATT_FREQ) {
timer_batt = millis();
//Serial.print("b");
msg[0] = SYNC;
msg[1] = BATTERY_LEVEL;
msg[2] = getBatt();
acc.write(msg, 3);
}
Make sure you're limiting the writing frequency, and reading quickly enough on both sides. There's a strange behaviour where the connection will appear to hang if there's too much data being buffered.

It's hard to say what to do without knowing what kind of data you are sending. Basically you have to make sure use the acc.write() method with the correct parameters. The first one is the byte array itself and the second one is the number of bytes in the array. So if your byte array is 5 bytes in size you need to call it like that: acc.write(msg, 5).
It is even better to make it more dynamic by using the sizeof Arduino function:
acc.write(msg, sizeof(msg));