Yeah, that's the values I'm talking about. It's very strange if the read values for 100kHz are that consistant regardless of the actual data being sent. It's something I'm wondering if it was a bug or whether there was a mistake of some description. If it's a bug, I might take a look.
I2C - Wire versus HardwareI2C versus Arduino Uno
(22 posts) (5 voices)-
IIRC we have a patch floating around for faster libmaple SPI speeds; mbolivar would know better but he's away this week.
Posted 2 years ago # -
gbulmer
Moderatormanitou - that is a pretty interesting set of stats. Do you intend to publish the programs used to get the I2C measurements?
I am a bit surprised about Maples slow software I2C. I'd expect it to pump bytes into an EEPROM at 100kHz as quickly as hardware I2C (using a lot more CPU cycles).
Posted 2 years ago # -
gbulmer
Moderatormanitou - "there are URL's to the test code in the first posting of this thread".
Ooops - Thanks!-)It might make it easier for folks to use your test code (for example if they want to improve code) if the code were in one of your github repos. Just a thought.
I am still puzzled why the Maple soft I2C is so much slower than hardware I2C. I'd expect the software and hardware I2C read times to be similar because I am pretty sure Maple can bit-bang at a lot better than 400kHz. However, I'm not going to worry about it; I'm confident someone will explain :-)
Posted 2 years ago # -
The Soft I2C is using DigitalWrite instead of using direct IO manipulations, there possible is a few other bottle necks as well. It's something I need to fix as well as some other bugs (which I have forgotten about which were found in this thread). The Software I2C is running about 88 kHz off the top of my memory. Since I have a logic analyser now, I can give a more precise measurement.
Posted 2 years ago #
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