DP83848I: DP84848 application questions

Kailyn Chen

Part Number: DP83848I

Hello,

Our customer met a question about the DP83848I application, his application diagram is as following:

The PC controls the relay on/off by the MCU of the device board, and then the relay control the AC contactor on/off.

The question is when controlling the AC contactor on/off, sometimes it would appear the Network communication interruption phenomenon. The test method is to control the AC contactor on/off with one per second frequency continuously, and each 10 minutes would appear the communication interruption, and also appear ping packet loss. But if he didn't control the AC contactor, the network is stable and work normally. (note: MCU work normally when network interrupt). And this time MCU couldn't receive data from DP83848, and the yellow LED of RJ45 couldn't bright.

Attached is the register data, when the network interrupt, the register 0X12 is always 0X0200, and the register 0X14 is 0X00ff. What is DP83848 status at this time? If he inserted and plugged the cable, the network would recover normally, or interrupt 5~6 seconds and then recover automatically.

Could you please help to analyze what is the main problem, EMI or the register configuration?

Dp83848 register during communication
Register Address：	0x01	0x04	0x05	0x06	0x07	0x10	0x11	0x12	0x14	0x15	0x16	0x17	0x18	0x19	0x1a	0x1b	0x1d
Communication Normally	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
AC contactor off/on （frequency about once per second continuous ）	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	200	b8	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	5b	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	59	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2c	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	5b	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2f	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	5b	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2e	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2e	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2b	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	1	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2f	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	2d	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	21	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	415	0	0	5a	0	100	29	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	615	0	0	0	0	100	21	0	8021	904	0	6011
Network interrupt	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	2d	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	25	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	29	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	21	0	8021	904	0	6011
	786d	101	cde1	0d	2801	e15	0	200	ff	0	100	2d	0	8021	904	0	6011

Best regards

Kailyn

over 3 years ago

0 Vikram Sharma over 3 years ago

TI__Genius 16030 points

Hello Kailyn,

It looks like there is a disturbance to PHY during AC control. Can there be ground bounce during switch on-off (when network interruption happens). Also did customer try the "software reset" as described in datasheet? May be software reset can be a possible solution to recover the communication after these interruptions.

Regards,

Vikram

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DP83848I: DP84848 application questions