Re: [beagleboard] RTC's SDA and SCL Resistors

I have 2 of them running here connected to BBGWs and performance is satisfactory so far. On Wednesday, July 26, 2017 at 7:48:18 PM UTC-4, john3909 wrote: > > This looks like a much better solution given that this module is powered > from 3v3. > > Regards, > John > -- For more options, visit

Re: [beagleboard] RTC's SDA and SCL Resistors

OK, if you read the datasheet, you will see VIH = 2v2 and VIL = 0v8, which means the I2C signals are compatible with a 3v3 pullups. The module you referenced has pullup resistors to 5v0, which means they must be removed. There are voltage convertors from TI for I2C devices, but in this case

Re: [beagleboard] RTC's SDA and SCL Resistors

Just to be clear, the Adafruit module has 2k2 resistors to 5V. These must be removed. However, the BBB still needs pullup resistors to 3v3. Regards, John > On Jul 26, 2017, at 1:42 PM, William B wrote: > > Hi! > I'm installing a real-time clock (RTC) on Beaglbone

Re: [beagleboard] RTC's SDA and SCL Resistors

Connect the pullup resistors to 3v3. Regards, John > On Jul 26, 2017, at 1:42 PM, William B wrote: > > Hi! > I'm installing a real-time clock (RTC) on Beaglbone Black and I'm seeing > divergent information abount hardware of the DS1307 integrated circuit, that >

[beagleboard] RTC's SDA and SCL Resistors

Hi! I'm installing a real-time clock (RTC) on Beaglbone Black and I'm seeing divergent information abount hardware of the DS1307 integrated circuit, that operates at 5V voltage, while the I2C IO buses of the BeagleBone operate at 3.3V. In the Adafruit RTC, they indicate removing the SCL and