YES!!!
not only that works but it got me much closer to answering some of my long
lingering questions about I2C. I can't keep working on this project until
next week so I might bug you again. but for now, thanks so much.
On Friday, March 21, 2014 5:03:49 PM UTC-4, Ytai wrote:
>
> Forgive me, I had originally misinterpreted what you're trying to do.
> The TWI interface only allows responses of size 254 or less.
>
> The good news is the you don't really need to dump the entire EEPROM if
> all you need is a small subset.
>
> You probably want something like:
>
> bool readEeprom(int start_address, byte[] result) {
> byte request[] = new byte[] { (byte) start_address };
> return twi_.writeRead(0x50, false, request, 1, result, result.length);
> }
>
> Then, you can call for example:
> byte[] result = new byte[2];
> if (readEeprom(247, result)) {
> // result[0] now contains the value in EEPROM address 247
> // result[1] now contains the value in EEPROM address 248
> }
>
> etc...
>
> If you need to dump the entire thing, just do two transactions of 128
> bytes or so.
>
> Similarly, you can write a simple writeEeprom() function for calibration.
> This would be a write-only operation (i.e. response is null and response
> size is 0), where the start_address sites the first byte of the request
> buffer, followed by the contents to be written starting at this address.
>
>
> On Fri, Mar 21, 2014 at 1:23 PM, Santiago Alfaro
> <[email protected]<javascript:>
> > wrote:
>
>> Hi,
>>
>> yes I have pull-ups to the 3.3 coming from the ioio and I have the sensor
>> on a separate source at 2.6 with all grounds connected.
>>
>> so what you mean is I should do this...
>>
>> *try {*
>> * Log.d(TAG, ":| Trying to read");*
>> * if (port.writeRead(address, false,
>> request,request.length,response,response.length)){*
>> * Log.i(TAG, ":) Got Initial response"); *
>> * for(int i=0; i<response.length; i++){*
>> * Log.i(TAG, "EEPROM Dump "+i+" = "+ response[i]);*
>> * if(i == 0xf7){*
>> * Log.i(TAG, "Triming Value = "+ response[i]);*
>> * }*
>> * }*
>> * }else{*
>> * Log.i(TAG, ":( NO response"); *
>> * }*
>>
>>
>> ... right? But then again I have the problem that when *response.length
>> = 255*, I get "*:( NO response"* but when *response.length = 120* I get
>> a bunch of numbers but not the one I need which is 247. I'm not sure if
>> that is part of the problem, but I'm curious since I don't know yet why
>> that happens.
>>
>>
>> On Thursday, March 20, 2014 8:12:44 PM UTC-4, Ytai wrote:
>>
>>> The writeRead() function returns a boolean that will be false in case
>>> anything goes wrong (for example, failing to get an ACK from the device).
>>> The contents of the response array do not matter, only its size.
>>> Do you have pull-ups on SDA and SCL?
>>>
>>>
>>> On Thu, Mar 20, 2014 at 2:29 PM, Santiago Alfaro <[email protected]>wrote:
>>>
>>>> Here is where I keep getting into trouble.
>>>>
>>>> I've tried with 0x00 meaning that
>>>>
>>>> byte[] request = new byte[] { 0x00 }; //Byte address to ask for sensor
>>>> data
>>>>
>>>> but that gives me an EEPROM dump of 0 and I know that is not right.
>>>>
>>>> I added the "0x50" on the request byte because I figured I was doing
>>>> something wrong and on the Datasheet it shows that EEPROM Dump has the
>>>> Slave Address and a Write, then the command (0x00) and then the
>>>> slaveaddress (again) and a Read so since just 0x00 was not working I tried
>>>> that and won't work either.
>>>>
>>>> How do I check for the return value of writeRead? won't that be the
>>>> actual EEPROM Dump that I get with the for loop?
>>>>
>>>> also, in the arduino code I can use this line i2c_start_wait(0xA0);
>>>> which Issues a start condition and sends address and transfer
>>>> direction. If device is busy, use ack polling to wait until device is
>>>> ready is there a way to do this with the ioio?
>>>>
>>>> Lastly, in playing with variables and trying things I realized that if
>>>> I have the response byte be { 0xFF } my EEPROM dump will be all 0. But if
>>>> I
>>>> change the response Byte to { 0x7F } then I get a bunch of numbers. I
>>>> don't
>>>> understand why the length of the response byte changes the values of the
>>>> response.
>>>>
>>>> Thanks
>>>> Santiago
>>>>
>>>>
>>>> On Wednesday, March 19, 2014 5:58:11 PM UTC-4, Ytai wrote:
>>>>
>>>>> You only need your twi write to be one byte long (0x00).
>>>>> Also make sure to check the return value of writeRead
>>>>> On Mar 19, 2014 2:29 PM, "Santiago Alfaro" <[email protected]> wrote:
>>>>>
>>>>>> Hello All
>>>>>>
>>>>>> I'm starting to get a handle on TWI on the ioio but I have not been
>>>>>> able to get an EEPROM dump from this sensor.
>>>>>>
>>>>>> The datasheet for the sensor can be found here
>>>>>> http://www.melexis.com/MLX90620
>>>>>>
>>>>>> and what I think are the relevant parts of it are these:
>>>>>>
>>>>>>
>>>>>> <https://lh4.googleusercontent.com/-DQO16I0bc_8/UyoLocosLAI/AAAAAAAAFU4/Df0qFbs20Xo/s1600/EEPROM.png>
>>>>>>
>>>>>> and
>>>>>>
>>>>>>
>>>>>>
>>>>>> <https://lh4.googleusercontent.com/-D2PP5yuAifY/UyoKBahwBOI/AAAAAAAAFUs/5NfmDToaRdc/s1600/ExportWholeEEPROM.png>
>>>>>>
>>>>>>
>>>>>> The code I have so far is this:
>>>>>>
>>>>>>
>>>>>> * twiEeprom = ioio_.openTwiMaster(0, TwiMaster.Rate.RATE_400KHz,
>>>>>> false); *
>>>>>>
>>>>>> * ...*
>>>>>>
>>>>>> * ReadEeprom(0x50, twiEeprom);*
>>>>>>
>>>>>> * ...*
>>>>>>
>>>>>> * public void ReadEeprom(int address, TwiMaster port) {*
>>>>>>
>>>>>> * byte[] request = new byte[] { 0x00, 0x50 }; //Byte address to ask
>>>>>> for sensor data*
>>>>>>
>>>>>> * byte[] response = new byte[ 0xFF ]; //Byte to save sensor data*
>>>>>>
>>>>>> * try {*
>>>>>>
>>>>>> * Log.d(TAG, ":| Trying to read");*
>>>>>>
>>>>>> * port.writeRead(address, false,
>>>>>> request,request.length,response,response.length);*
>>>>>>
>>>>>> * for(int i=0; i<response.length; i++){*
>>>>>>
>>>>>> * Log.i(TAG, "EEPROM Dump "+i+" = "+ response[i]);*
>>>>>>
>>>>>> * }*
>>>>>>
>>>>>> * Log.d(TAG, ":) success reading");*
>>>>>>
>>>>>> * ...*
>>>>>>
>>>>>> My problem is that I keep getting all zeros on the EEPROM Dump. I
>>>>>> know I'm correctly connected because it works on an Arduino. (also
>>>>>> because
>>>>>> I already burnt a IOIO trying to figure another thing out :D but now the
>>>>>> new one is surviving )
>>>>>>
>>>>>>
>>>>>> Is there anything that jumps out that I'm doing wrong? I can send
>>>>>> more detail if needed.
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Santiago
>>>>>>
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>
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