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TLK110: LED_ACT Mode 1 configuration and Mode 1 pulse timming

Zhou Fang67
Expert 4250 points
Part Number: TLK110

Hi Expert,

Problem:

In MODE1, LED_ACT pin with LED should be blinking when data is transmitting or receiving(ON), OFF when there is no data transmitting. In customer's board, the LED_ACT pin only perform a very short "OFF" pulse.  LED is always "ON". When there is no data is transmitting, the LED is still "ON".

Could you please help to see is there any configuration that related to LED_ACT behaviors? 

HW Configuration:

1. CRS pin is floating to use LED_ACT MODE1.

2. LED_ACT pin is pulled to VCC with LED and resistor.

LED_ACT pulse timing at Mode 1:

Pin: LED_ACT

Short pulse can be observed on LED_ACT pin. Period is 2.8 Hz, "High" logic period is around 200us. 

Thanks a lot.

Zhou

  • 0
    TI__Mastermind 23675 points
    Hi Zhou,

    Please send me a schematic so i can confirm HW implementation.

    Thank you,
    Ross
  • 0 in reply to Ross Pimentel
    TI__Expert 4250 points

    Hi Ross,TLK110.pdf

    The schematic is on attachment.

    Thanks.

    Zhou

  • 0 in reply to Zhou Fang67
    TI__Mastermind 23675 points
    Hi Zhou,

    You are able to send and receive error free data when this condition occurs as well?
    Have you checked to confirm LED_ACT is not configured for collision detection using register read?
    Can you tell me what the value of register 0x19h is?

    Thank you,
    Ross
  • 0 in reply to Ross Pimentel
    TI__Expert 4250 points

    Hi Ross,

    On this condition, TLK110 can pass Ethercat test and data can be received and transmitted successfully.

    We have re-produced this issue on TI reference design with TLK110:

    Reading from 0x0019 is 8823 with MODE 1, and we found:

    Mode 1:

    LED_LINK: ON

    LED_ACT: ON (Transmitting & Receiving)

    Mode 3:

    LED_LINK: Blinking (Transmitting & Receiving)

    LED_ACT: ON

    Which means the activity is actually happened, in Mode 3, LED_LINK was blinking with 5Hz. However, there is some problem for LED_ACT pin. LED_ACT should be the same activity as LED_LINK in Mode 1, but it is not.

    Thanks.

    Zhou

  • 0 in reply to Zhou Fang67
    TI__Mastermind 23675 points
    Please send the register dump when the issues occurs. Otherwise I cannot continue to debug this issues.

    Thank you,
    Ross
  • 0 in reply to Ross Pimentel
    TI__Expert 4250 points
    Hi Ross,

    You need all registers' readings?
    reading from 0x0019 is 8823.

    Thanks a lot.
  • 0 in reply to Ross Pimentel
    TI__Expert 4250 points

    Hi Ross,

    In datasheet, LEC_ACT is ON(pulse), not blink. Could you please help to see if the waveform is normal or not?

    The register readings have been attached.

    Fullscreen Register when LED_ACT does not blink.txt Download 
    reading.txt file is open...
Register 0000 is: 3100

Register 0001 is: 786D

Register 0002 is: 2000

Register 0003 is: A211

Register 0004 is: 01E1

Register 0005 is: 41E1

Register 0006 is: 0005

Register 0007 is: 2001

Register 0008 is: 0000

Register 0009 is: 3C00

Register 000A is: 0104

Register 0010 is: 0615

Register 0011 is: 0108

Register 0012 is: 0000

Register 0013 is: 0000

Register 0015 is: 0000

Register 0016 is: 0100

Register 0018 is: 0400

Register 0019 is: 0821

Register 001B is: 007D

End of file.

    Thanks.

    Zhou

  • 0 in reply to Zhou Fang67
    TI__Expert 4250 points
    Hi Expert,

    Is there any clarification for LED_ACT behavior? How to determine the link is on activity or not?

    LED_ACT:
    ON PUlSE for ACTIVITY
    OFF for NO_ACTIVITY

    Thanks.
    Zhou