I2C noise into the audio signals

Started by Anonymous in sci.electronics.design4 years ago 19 replies

We have TDA7719 audio processor and OLED display connected to the same I2C = bus as I2C slaves. Both the devices are driven by MCU which is I2C...

We have TDA7719 audio processor and OLED display connected to the same I2C = bus as I2C slaves. Both the devices are driven by MCU which is I2C master. = After TDA7719 is initialized with I2C for input selection and volume, it st= arts working. The MCU keeps refreshing the display by continuously writing = data to the display through the same I2C bus. This I2C noise is getting cou= pled into ...


I2C Level Translator

Started by Tim Wescott in sci.electronics.design2 years ago 19 replies
I2C

So, I was happily working away, designing in a 2.5V part to talk to the I2C bus from a 5V processor, when reality caught up to me. 2.5V. 5V....

So, I was happily working away, designing in a 2.5V part to talk to the I2C bus from a 5V processor, when reality caught up to me. 2.5V. 5V. I2C. It appears that NXP has some I2C level translators -- does anyone have any mileage with them? Do they work? Anyone have any parts to either embrace or avoid? I can certainly see some issues with trying to make it all reliable, and back...


Painless I2C reading

Started by Phil Hobbs in sci.electronics.design6 years ago 45 replies
I2C

Hi, all, For a patent infringement case, I need to dump the contents of a small I2C EEPROM (an Atmel AT24C01A). I've actually never used an...

Hi, all, For a patent infringement case, I need to dump the contents of a small I2C EEPROM (an Atmel AT24C01A). I've actually never used an I2C part--I sort of standardized on SPI at an early age and never deviated, mostly because I never needed multi-master and had heard evil things about I2C reliability. So I have zilch equipment to do this. Does anyone have a painless way to do ...


I2C to PWM IC

Started by Michael in sci.electronics.design2 years ago 17 replies

Does anybody make an IC that takes I2C command and outputs duty cycle (PWM)? I need to control bunch of TECs from CPU and I2C-> PWM seems the...

Does anybody make an IC that takes I2C command and outputs duty cycle (PWM)? I need to control bunch of TECs from CPU and I2C-> PWM seems the most efficient (and smallest) way to do it. Any suggestion will be appreciated. Thanks Michael


I2C switch/multiplex

Started by Mikko OH2HVJ in sci.electronics.design11 months ago 2 replies

I've got a task of cramming in a GPS receiver with I2C interface to an existing small board. The receiver is rather power hungry (50uA) even in...

I've got a task of cramming in a GPS receiver with I2C interface to an existing small board. The receiver is rather power hungry (50uA) even in sleep mode compared to the target of 3uA at 2.8V. I was planning on isolating the GPS receiver from the system with a P-fet in the power line and analog dual switch on the I2C lines. These being controlled PCA9570 or similar I2C GPIO extender. Al...


I2C master

Started by David Lesher in sci.electronics.design2 months ago 35 replies
I2C

In theory, I2C handles multiple masters. Wonder if anyone is doing so, and if so, how hard was it to get up & running? -- A host is a...

In theory, I2C handles multiple masters. Wonder if anyone is doing so, and if so, how hard was it to get up & running? -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead..


I2C relay boards.

Started by David Lesher in sci.electronics.design3 weeks ago 16 replies
I2C

I have need for a 8-16 channel I2C in, relay out expansion board. We're now using: but the shipping is insane. So I'm seeking an...

I have need for a 8-16 channel I2C in, relay out expansion board. We're now using: but the shipping is insane. So I'm seeking an alternative supplier. I figure one approach is to find a forum where Arduino users hang out, and ask there. Any suggestions for board suppliers or forums? -- A host is a host from coast to coast..


How about it? Experiments of the third kind , take 999999.

Started by Jan Panteltje in sci.electronics.design6 years ago 32 replies

Design changes: Acquisition data will be stored in a 24LC256 i2c serial EEPROM (on order). I ran out of enough code space in the 18F14K22 to...

Design changes: Acquisition data will be stored in a 24LC256 i2c serial EEPROM (on order). I ran out of enough code space in the 18F14K22 to store 8760 x 2 bytes (24 hours x 365 days), as I have a lot of extra test stuff added. Now I have 32 kB. As the 18F14K22 SPI is broken, and the i2c uses the same hardware, I wrote i2c software today to write and verify the data, just in case. I rep...


PIC daughterboard detection

Started by Randy Day in sci.electronics.design3 years ago 8 replies
I2C

I'm wanting to have a PIC detect whether a daughterboard is present, so it can activate I2C comm. My thought is to activate the weak...

I'm wanting to have a PIC detect whether a daughterboard is present, so it can activate I2C comm. My thought is to activate the weak pull-down on the input, to detect whether an I2C pull-up resistor (10k) is present on the line, before turning on I2C. Is this an acceptable use of the weak pull-down features of the PIC? I'm a bit unclear on the do's and don'ts of WPU/WPD. (terr...


Muxing I2C question

Started by Mook Johnson in sci.electronics.design3 years ago 2 replies
I2C

I have an application where I have 8 identical I2C devices that I cannot change the address on. I need to talk to all 8 in sequence and...

I have an application where I have 8 identical I2C devices that I cannot change the address on. I need to talk to all 8 in sequence and considering a 1:8 MUX. I'm pondering if I need to MUX both the SCL and SDA lines. If I mux only the SCL line so only the one I'm talking to sees the clock, but all of them see the activity on SDA would the device care. I wouldn't think so becau...


I2C bus needs capacitance?

Started by DemonicTubes in sci.electronics.design1 year ago 43 replies

I've got a couple boards that use this method to level shift: http://imgur.com/a/yjD58 The I2C master is 3.3V while all the slaves are 5V...

I've got a couple boards that use this method to level shift: http://imgur.com/a/yjD58 The I2C master is 3.3V while all the slaves are 5V devices. This works fine, except on the newest board. Only one of the (3 in this case) slaves respond. Scoping the wave-forms and comparing with another board with the same circuit (different PCB layout, however) shows they are identical...until


Output boards, SPI vs I2C

Started by David Lesher in sci.electronics.design8 months ago 25 replies
I2C

I pondering a microcontroller project that will need a number (say 24) output relays. Is there a reason to use I2C over SPI? It looks like...

I pondering a microcontroller project that will need a number (say 24) output relays. Is there a reason to use I2C over SPI? It looks like there are 8-channel boards of both ilks, and I don't know if one has an advantage in this case. -- A host is a host from coast to coast.................wb8foz@nrk.com & no one will talk to a host that's close.......................... Unless the hos...


Wow 460800 Bd via USB to serial adaptor works!

Started by Jan Panteltje in sci.electronics.design5 years ago 1 reply

Wow 460800 Bd via USB to serial adaptor works! Wanted to add a par port to my laptop, or at least some I/O pins. At 460800 Bd you can send a...

Wow 460800 Bd via USB to serial adaptor works! Wanted to add a par port to my laptop, or at least some I/O pins. At 460800 Bd you can send a byte in 2.17 uS. That means if I want to test I2C chips via USB to RS232 adaptor, and use only one state flip per bit, something that requires 4 bytes RS232 per I2C bit processing, for example: SDA high SCL high SCL low SDA low makes 10.8 ...


connecting 2 keypads on rsp

Started by gm in sci.electronics.design12 months ago 6 replies
I2C

Hi to all. Because of the amount of the system users ( cca 500 of them ) i need to setup some 4x5 or 4x6 keypad. To do so am planning to use...

Hi to all. Because of the amount of the system users ( cca 500 of them ) i need to setup some 4x5 or 4x6 keypad. To do so am planning to use some standard 4x4 + one 2x4 keypad over i2c. Should this be problem to construct in the way that the second keypad is recognized as extension of the first one ? So 1-16 --- 17-24 GM


Sigma delta audio dacs

Started by bitrex in sci.electronics.design2 years ago 13 replies
I2C

I'd like to drive 6 channels of 16 bit, 44.1 kHz audio out of an ARM Cortex M4 processor, using i2c I guess. There are so many DACS out...

I'd like to drive 6 channels of 16 bit, 44.1 kHz audio out of an ARM Cortex M4 processor, using i2c I guess. There are so many DACS out there...so this is another one of those "so what is cheap and worked good for you" kind of questions. -- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/


Experience with MCP7940?

Started by Tim Wescott in sci.electronics.design2 years ago 8 replies
I2C

I'm getting the software going for a MCP7940, and the I2C interface is giving me fits. This is with software that worked fine for a couple of...

I'm getting the software going for a MCP7940, and the I2C interface is giving me fits. This is with software that worked fine for a couple of ST inertial sensors. Has anyone had success or failure with this part? I'm getting ever- deeper into this, but at the moment it appears that the data is getting written and read correctly, but I'm getting NACKs at the ends of transfers. -- ...


Sound chips that natively go to DC?

Started by Joerg in sci.electronics.design4 years ago 20 replies

Folks, The subject pretty much says it. Are there any that can at least be coaxed into DC input and output by disabling internal cancelers...

Folks, The subject pretty much says it. Are there any that can at least be coaxed into DC input and output by disabling internal cancelers and such? Should not be too drifty. The digital interface doesn't matter much, USB, SPI, whatever. Preferably not I2C but even that would be ok. 16 bit would suffice. Of course, more is better. Input to output synchronicity is important, as usual. Als...


Drivings LED with limited pins

Started by Mike Miller in sci.electronics.design4 years ago 63 replies

All, I want to be able to toggle 23 separate LEDs in my application. The design challenge is that I only have about 17 pins available on my...

All, I want to be able to toggle 23 separate LEDs in my application. The design challenge is that I only have about 17 pins available on my SoC. What are some options for this? 1.) Use another microcontroller with 23 available pins with some digital interface (spi/i2c) and then send over data to toggle the appropriate pins? 2.) Ideally I don't want to have to do additional firmware de...


ATTiny ADC and TWI

Started by bitrex in sci.electronics.design1 year ago 3 replies
I2C

Looking at the ATTiny datasheet...why oh why do they put one of the ADC channels on the SCL pin? So it seems if you want to use all four ADC...

Looking at the ATTiny datasheet...why oh why do they put one of the ADC channels on the SCL pin? So it seems if you want to use all four ADC channels, it's not possible to connect the uC to an i2c bus.


logic generator

Started by Anonymous in sci.electronics.design8 years ago 27 replies
I2C

Is there a device like a "reverse" logic analyzer? Say 30 outputs and I can program what shows up on each pin in time? Suppose I want to shift...

Is there a device like a "reverse" logic analyzer? Say 30 outputs and I can program what shows up on each pin in time? Suppose I want to shift out 288 bits on a SPI style setup at 30MHz, then generate a few 10ns strobe signals on other lines. I have a few gizmos like the Aardvark that let me generate I2C streams and have a few GPIO lines, but nothing to let me use them quickly. I'd like a GU...