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TL16C752D: TL16C752DPFBR

Mukke Sandeep
Prodigy 20 points
Part Number: TL16C752D

Tool/software:

Hi,

We are using the TL16C752DPFBR Dual UART, parallel interface with ATMEGA2560 MCU, 

While we are executing the code to get the registers data on data lines from UART chip we are facing the issues on register values mismatch...we have verified the code properly

I'm attaching the UART & MCU schematic images for the verification of the functionality...

    

Also i'm attaching the observed serial data for UART register values below

LCR and IER registers are working fine

" SUCCESS: LCR SHOULD BE 0x03
LCR ACTUALLY = [0x03]

SUCCESS: IER SHOULD BE 0x03
IER ACTUALLY = [0x03]

ERROR: IIR SHOULD BE 0xC1
IIR ACTUALLY = [0x03]

ERROR: MSR SHOULD BE 0x00
MSR ACTUALLY = [0x03]

ERROR: MCR SHOULD BE 0x08
MCR ACTUALLY = [0x03]

ERROR: EFR SHOULD BE 0x02
EFR ACTUALLY = [0xBF]

ERROR: AFR SHOULD BE 0x14
AFR ACTUALLY = [0x83]

ERROR: TLR SHOULD BE 0xFF
TLR ACTUALLY = [0x43]

ERROR: TCR SHOULD BE 0x00
TCR ACTUALLY = [0x43]

ERROR: FRR SHOULD BE 0x00
FRR ACTUALLY = [0x03 ] "

Could you please verify and clarify on why these errors are getting on the registers

  • 0
    TI__Guru 52282 points

    Hi Mukke,

    Our UART expert is currently out of the office - they should be returning later this week. I apologize for the delay and appreciate your patience here while our expert is out of office. 

    Best,

    Parker Dodson

  • 0
    TI__Guru 73271 points

    Mukke,

    Can you verify the RESET pin is properly biased and isn't toggling once it powers up? I believe when this kind of error occurs it may be because of the reset pin. 

    You may also want to probe XTAL1 to see if it's getting a good clock signal.

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 20 points

    hi,

    as per you suggestion i tested the RESET and CLK functionalities

    1. Before mentioning about RESET section, as per the attached schematic image just verify the RESET pin connection to GND, As per data sheet it is "active high logic pin" 
    to do the normal operation of UART i tied RESET pin to GND through R136 (10k res). So i didn't found any toggling situation

    2. Proper lock signal at XTAL1- Pls find the attached sch image for crystal part and connection details
        Observed the Proper 18.432MHz clock signal at XTAL2 not on XTAL1, i didn't found any signal on XTAL1

  • 0 in reply to Mukke Sandeep
    TI__Guru 51256 points

    Hi Mukke,

    Today is a holiday. Please give some time until Monday for feedback, thanks.

    Best Regards,

    Michael.

  • 0 in reply to Mukke Sandeep
    Prodigy 20 points

    i tested the XTAL signals, Proper signal is coming on XTAL1 and XTAL2 pins
    i tested the board with Manually reset the IC after power up, still i'm not getting all register values, pls check the the attached results

    rs485UartReadMSRTest: MSR[0xF0]-FAIL

    rs485UartReadIERTest: IER[0x00]-FAIL

    rs485UartReadIIRTest: IIR[0x01]-FAIL

    rs485UartReadLCRTest: LCR[0x03]-PASS

    rs485UartReadMSRTest: MSR[0xF0]-FAIL

    rs485UartReadMCRTest: MCR[0x00]-FAIL

    rs485UartReadEFRTest: EFR[0x00]-FAIL

    rs485UartReadAFRTest: AFR[0x10]-FAIL

    rs485UartReadTLRTest: TLR[0x00]-FAIL

    rs485UartReadTCRTest: TCR[0x00]-PASS

    rs485UartReadLSRTest: LSR[0x60]-PASS

    rs485UartReadFRRTest: FRR[0x00]-PASS

    pls try to replay asap, we don't have a time

    We found same issue in all 10 boards...

    and are there any possibility of ICs defective?

  • 0
    Prodigy 20 points

    hi    

    Till now i didn't get any reply from any of you...

  • 0 in reply to Mukke Sandeep
    TI__Guru 73271 points

    Hi Mukke,

    Sorry I think the thread status was moved/filtered to inactive until your latest comment so I couldn't see it until now. 

    Can you put the RESET pin and the CSB pin on an o-scope and redo your testing to see if they ever toggle during the test? I'm wondering if you're the CSB or the RESET pin is changing state at any point during the write/read tests. (maybe due to noise)

    Can you also walk me through the initialization of the code and the write/read checks?

    example:

    1) Write LCR=0xFF 

    2) Write DLL=0x03

    ect.

    Are you reusing code from the 752B device?

    Mukke Sandeep said:

    We found same issue in all 10 boards...

    and are there any possibility of ICs defective?

    Are 10/10 boards having the same issue (meaning you have zero passing units?)

    If you have no passing units I would suspect the issue is some sort of system level problem. 

    -Bobby

  • 0 in reply to BOBBY
    Prodigy 20 points

    Hi  
    We are able to communicate the IC, RESET the IC at initial power on with ms delay then it is working perfectly.. thanks for the support

    i'll get back to you if anything required