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Need I2C implementation

(10 posts) (3 voices)

Started 5 years ago by Kenny9999
Latest reply from poslathian

Kenny9999
Member

I order my maple and I gone get it this week I thing

Already have an arduino nano 328 and I need more room for my program, so I check around and found 2 alternative, the maple and the seeeduino mega. But, I'm interested in the power and the 32bit version of the maple over the seeeduino mega. I plan to have a lot of I2C device connected. Just now, I plan to have like 9 device connected to I2C for my project.

So, just wondering if you guy's are working on I2C and plan to add it in the 0.0.7 version?

Posted 5 years ago #
Kenny9999
Member

Just download the maple-ide-0018 from http://code.google.com/p/leaflabs/downloads/list

I see there is some I2C sample but, no luck at compile time

got that error
#############################################################################
Going to build using 'make' (ARM)
Compiling core arm-none-eabi

C:\Program Files\maple-ide-0018\hardware\leaflabs\cores\maple\wiring.c: In function 'NVIC_Configuration':

Compiling any libs with arm-none-eabi

C:\Program Files\maple-ide-0018\libraries\Wire\utility\twi.c:23: fatal error: avr/io.h: No such file or directory

compilation terminated.
########################################################################

look to me that the porting is not far then to be completed!

I'm on windows, is there any change to get that working on linux? not real good in linux, but, can give a try!

Posted 5 years ago #
poslathian
LeafLabs

Im working on porting a soft implementation of the "Wire" library right now! By soft I mean that the i2c is done via bitbanging rather than the hardware i2c driver. This is suboptimal, but i2c is a fairly slow protocol (400KHz in fast mode) so the only real hit is that it will be synchronous rather than async. I will post when this is done so you can use it!

Posted 5 years ago #
Kenny9999
Member

Great thank! can't wait to see what that baby have to give, but, I'll need the I2C implementation! My need of speed is about 500KHz, but 400 will be enough to start! Just let us know when it will be available!

Posted 5 years ago #
gbulmer
Moderator

While I2C is quite slow by comparison with e.g. SPI, there are two I2C peripherals on the STM32F103RB, so if it's feasible to get the hardware peripherals working, there would be both better throughput, and potentially lower latency if the I2C devices are well balanced across the two 'buses' (assuming devices are all slaves).

(I realise this is non-trivial)

Posted 5 years ago #
Kenny9999
Member

Hardware would be nice, but, since it's hard and complicated, A soft one will be enough to start with. I saw the Maple many time in some forum, At least on Aeroquad and DIYDrone. The maple seem a great product and to give it some popularity, a fast implementation of compatible arduino library will help a lot. I'm not really good in micro controller and electronics, but, I manage to do a lot of thing just by copying some code for the arduino and adapt it! It's simple and easy to understand and it is working and fast to get result.

for nOOb like me, it's cool to get something working fast and easily!

Posted 5 years ago #
poslathian
LeafLabs

The I2C hardware is really designed to be used the DMA. At first setting up the DMA was way below i2c on our priority queue, so we tried to setup a HardwareI2C interface without DMA. We failed miserably after two fully fledged attempts. So, were releasing a hold-over soft implementation and moving DMA up the queue to (next!), then well setup the i2c peripheral using DMA.

tldr: i2c om nom nom

Posted 5 years ago #
poslathian
LeafLabs

speaking of performance, the hardwarei2c is actually built in to run kind of slow, because thats the i2c spec. Im not sure how much you can overdrive it past 400KHz. However the soft i2c should run in the low MHz, probably 1-3, I had some macro'd fast implementation running at nearly 5MHz, but Im not going to optimize for code size rather than speed in the SoftwareI2C interface.

Posted 5 years ago #
Kenny9999
Member

Well, I'm there now.

I received my Maple board, and now, I want to start interfacing with my I2C device, I search a bit to find something, even low level, that I can used on the forum but, no luck, or I may be blind!

I read a bit of
http://forums.leaflabs.com/topic.php?id=121
Imported some of the code in the IDE and was not able to compile it. Then I look at the SPI implementation and find out that was not what I was thinking! I learn what it is actually a bit more. "Like I said, not really a low level guy"

So, In the documentation:
http://leaflabs.com/docs/maple/i2c/
I have found in this page that the I2C is in development, like written in the previous post. But, it's also written that the interface is available in the I2C branch of libmaple here http://github.com/leaflabs

I search on the libmaple and did not find any reference to I2C

Have you something for me that I can play with it? Even those function describe here http://forums.leaflabs.com/topic.php?id=28 would be appreciate! or pin point me to some implementation "compiling on win" that I can use!

Any help would be appreciate!

I want to interface 2 ITG3200 gyro and 2 BMA180 accelerometer to do an IMU

Thank in advance!

Posted 5 years ago #
poslathian
LeafLabs

Let me bang out an alpha version of the Wire library for you to play with before 0.0.7 Ill post later in the day.

Posted 5 years ago #

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