Doing an AIO read

[arfoll]

I want to read A0 on my board, I'm not entirely sure how this works, and there's no example so was trying to write one. So far I have something like this:

firmata = firmata_new("/dev/ttyACM3");
firmata_pinMode(firmata, 14, MODE_ANALOG);
while(1) {
  firmata_pull(firmata);
  printf("read value: %d\n", firmata->pins[14].analog_channel);
}

Is 14 A0? or is it 0? And I'm guessing that doing the pull means I update the data available in t_firmata which is what I want but do I need the pinMode call and do I need to do someting else first like register for ADC updates/ask for it? Can I ask for just A0?

Similarly have you got any examples of how someone would do some i2c or spi?

[arfoll]

So the best I have is that firmata_pull doesn't seem to ever pull anything, however if I use firmatajs it works well. I got a little further by enabling VMIN=1 on the tty and started getting alot of garbage but still didn't get the 'ready' signal.

[grandsmarquis]

Hello @arfoll I'm sorry I don't have much time in this month to check your problem. Maybe there is an issue. Please continue writing here if you find anything.

[arfoll]

No problem - just posted this in blind hope :) I'm working with a Genuino 101 so maybe that's my problem, I've made it work (kindof) now, instead of 14 you have to ask for 0 for A0 interceptty is working really well for debugging this, I get the feeling part of the issue is the way the serial.c sets up the serial port, it works without any issues from firmatajs and I still don't really understand why.

[pastranacl]

HI Both,

First let me congratule you Mr. Dourlens for this library. I think its a nice work and it took me a while to find a nice library for C and Firmata. I have the same problem than arfoll using Arduino UNO. I wrote it in this way:

int MY_PIN = 0; firmata_pinMode(firmata, MY_PIN, MODE_ANALOG); firmata_pull(firmata); int output = firmata->pins[MY_PIN].value ;

This is what I understood based on the available documentation. However, I had the same doubt about A0 (pin 0 vs 14) and seeing that there was no signal I decided to do for loop to scan pins. All pins return 0.

Thanks is advance.

All the best,

CLP

[arfoll]

Keep pulling, you've only just started receiving sysex messages you can't guarantee the next one is what you want (check with gdb when you get it in firmata_parse if you want). It's 14 for aio0.

FYI I used firmatac as the basis for intel-iot-devkit/mraa reading code in src/firmata/firmata_mraa.c to see how I call it that may help. I also modified firmata.c to do some i2c. On 5 Jun 2016 01:43, "pastranacl" notifications@github.com wrote:

HI Both,

First let me congratule you Mr. Dourlens for this library. I think its a nice work and it took me a while to find a nice library for the C and Arduino. I have the same problem than arfoll using Arduino UNO. I wrote it in this way:

int MY_PIN = 0; firmata_pinMode(firmata, MY_PIN, MODE_ANALOG); firmata_pull(firmata); int firmata->pins[MY_PIN].value ;

This is what I understood based on the available documentation. However, I had the same doubt about A0 (pin 0 vs 14) and seeing that there was no signal I decided to do for loop to scan pins. All pins return 0.

Thanks is advance.

All the best,

CLP

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/jdourlens/FirmataC/issues/2#issuecomment-223786371, or mute the thread https://github.com/notifications/unsubscribe/AAfZZh3_uG9LxjsxHBL3lEhQs6Gcb3syks5qIhukgaJpZM4HcJWB .

[pastranacl]

Thanks for the fast answer @arfoll. First let me admit that my knowledge of i2c and hardware programming is almost null. I took a look at your mraa codes. I found your function for analog reading but because it calls to mraa_uart_write and this itself to others, it would a mess to me, because I have already implemented the codes for other functions using @jdourlens' FirmataC. I'm aware that someone with more experience and knowledge could extract how to split Firmata's messages to extract the analog value based in both codes.

Following your suggestion I included a calling to this function in a while loop

if ( firmata->pins[pin].mode != MODE_ANALOG ) firmata_pinMode(firmata, pin, MODE_ANALOG); firmata_pull(firmata); firmata_pinMode(firmata, pin, MODE_ANALOG); return firmata->pins[pin].value;

The returned values are always 0. Surprisingly, for every calling of the function, it is printed Setting pinMode at: 0 with value: 2

Could this be the problem? By some reason the analog pin is not set to MODE_ANALOG. Or the state of the pin is not determined correctly. BTW: What is the meaning of firmata->pins[14].analog_channel? I always obtain 127 for every pin.

In the end my objective is to obtain in real-time the data in the given analog pin for a measurement apparatus. I did that previously in MATLAB and it worked nice.

Thanks,

Best