I2C noise into the audio signals

Started by Anonymous in sci.electronics.design9 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 to PWM IC

Started by Michael in sci.electronics.design7 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


Super-slow I2C edges?

Started by Phil Hobbs in sci.electronics.design1 year ago 19 replies

So we're building these reasonably-swoopy SiPM/MPPC/APD modules, and we need to temperature-compensate the gain and dark current, as well as...

So we're building these reasonably-swoopy SiPM/MPPC/APD modules, and we need to temperature-compensate the gain and dark current, as well as keeping track of the relative humidity so we don't get condensation. In the scheme of things, this means running digital lines out to muxes, dpots, DACs, and sensors. This version uses I2C for everything. Simon has done I2C stuff many times, but ...


i2c pull up resistor situation

Started by bitrex in sci.electronics.design2 years ago 16 replies

These little "Digistump" Velleman boards with an ATTiny85 on them are handy, but because they're intended to be programmed directly over...

These little "Digistump" Velleman boards with an ATTiny85 on them are handy, but because they're intended to be programmed directly over USB compromises have to be made: The 1.5k pullup on the ADC input pin "D-" can be worked around. Trying to run low-speed software i2c over pin "D+" and PB5/nRES doesn't seem to work


I2C cable

Started by Winfield Hill in sci.electronics.design3 years ago 46 replies

We need a 1-meter length of 100kHz (or slower) I2C onnection. It'd be nice to use a pre-made cable: micro-USB, 4-wire RJ11, or RJ45...

We need a 1-meter length of 100kHz (or slower) I2C onnection. It'd be nice to use a pre-made cable: micro-USB, 4-wire RJ11, or RJ45 ethernet. Some considerations: SCL and SDA crosstalk(?), high ground capacitance. Also need 3.3V, Gnd. Micro-USB: SCL and SDA twisted together, bad? RJ11: flat, SCL and SDA on outside lines? RJ45: SCL and SDA shielded from each other. -- Thanks, ...


Battery Changing issue

Started by Ed Lee in sci.electronics.design9 months ago 17 replies

I am using these batteries. Discharging from the (BMS managed side) 8 pins connector seems OK, but charging is not working. It might need the I2C...

I am using these batteries. Discharging from the (BMS managed side) 8 pins connector seems OK, but charging is not working. It might need the I2C control to enable charging? With the battery at 10V, hooking up a 11V supply doesn't seem to do any thing, with the voltage coming up to 11V immediately. Someone reported good result with 12V+ adjustable supply. Hooking up to the inte


AGP30, issues with CO2 VOC sensor

Started by Winfield Hill in sci.electronics.design3 years ago 27 replies

Has anyone here used the Sensirion AGP30, a tiny I2C sensor for CO2 and VOC gases? It takes about 60mA to heat a hot plate, and it needs at...

Has anyone here used the Sensirion AGP30, a tiny I2C sensor for CO2 and VOC gases? It takes about 60mA to heat a hot plate, and it needs at least 15 seconds to start reading data. But ours is experiencing shutoffs after 1.8 seconds when we run it from a Feather, but not if we run it from a Raspberry Pi. Both controllers feed the PCB with 3.3 volts, where its regulated down to ...


I2C devices with unique identifiers.

Started by Roberto Waltman in sci.electronics.design10 years ago 14 replies
I2C

For a project I am working on, I would like to give boards fresh from manufacturing a distinct "identity", before they are assigned a...

For a project I am working on, I would like to give boards fresh from manufacturing a distinct "identity", before they are assigned a serial number, or have a MAC address or IP address programmed, etc. This could be provided by some devices, such as Maxim's DS2411 "Silicon serial number" ( with a "Unique, Factory-Lasered and Tested 64-Bit Registration Number" ) or DS18B20 temperature sens...


Wrote a program for Raspberry Pi 4 to drive small 128x64 pixels OLEDs, any interests?

Started by Jan Panteltje in sci.electronics.design5 months ago 6 replies

Wrote a program for Raspberry Pi 4 to drive small 128x64 pixels OLEDs this uses GPIO pins and Linux kernel i2c. The C code does _not_ depend...

Wrote a program for Raspberry Pi 4 to drive small 128x64 pixels OLEDs this uses GPIO pins and Linux kernel i2c. The C code does _not_ depend on other libraries, and just compiles with gcc. It can put small, big and huge text anywhere on the 128x64 OLED, and even display 128x64 bitmaps. +3.3V, SDA SCL and ground from GPIO. If there is any interest here let me know in the group, then I ca...


RIS-797, programmable isolated current-source charge-pulser

Started by Winfield Hill in sci.electronics.design3 years ago 1 reply

The RIS-797 project is for an isolated, programmable current-source charge-pulser, using the op-amp MOSFET techniques analyzed in...

The RIS-797 project is for an isolated, programmable current-source charge-pulser, using the op-amp MOSFET techniques analyzed in x-Chapters 4x.26. This uses four 0.5pF isolator channels to run an I2C DAC and the current-source, including a range switch. Total output node capacitance to ground = 5pF, mostly due to DC-DC power-supply module. Two-terminal floating current sources...