EV2400: Power management forum

wen xiao

Part Number: EV2400
Other Parts Discussed in Thread: BQSTUDIO

Expert，Hello:

When using EV2400 for I2C communication, the communication waveform is abnormal, and the waveform of the rising edge is displayed incorrectly. This problem will not occur when using EV2300.
The abnormal waveform is as follows:

100K: 400K:

EV2400 can be used normally, the waveform is as abnormal after replacement.

This anomaly caused us to capture the 400K waveform of the communication frequency, and the waveform delay was completely wrong. Could you please help us to avoid this problem?

over 4 years ago

0 Shirish over 4 years ago

TI__Guru 57697 points

Hello Wen,

There is too much capacitance on the lines. Reduce the length of the wires or increase the strength of the pullups. The problem will be seen at higher speeds. Therefore it is not seen with EV2300 which cannot do 400KHz

0 wen xiao over 4 years ago in reply to Shirish

Prodigy 140 points

Hello expert：

I am using a 2400 box for I2C communication, and the same problem occurs at 100K frequency, but there is no capacitor on the battery communication line；

We use the 2400 box matching cable to connect to the computer. If the cable is too long, does it mean to reduce the length of the cable?

0 Shirish over 4 years ago in reply to wen xiao

TI__Guru 57697 points

Hello Wen,

The capacitance comes from the wires and boards. You may reduce the length of the wires to reduce capacitance. However there is no need to do so for 100KHz. The waveform @ 100KHz looks fine for communication. The threshold level is what matters, the curved portion above the threshold does not matter.

You can confirm by checking that the data read from bqStudio is correct at 100KHz.