[J6] UART5 can not receive data

Andy Huang18

Hi ,

We have two J6 custom boards (SDK 7.04.00.03) as mother board and daughter board . Their UART5(ttyS4) ports connect to each other.

But after running our production line program couple hours, there is one J6 board UART5 can not receive data anymore , but this J6 UART5 can still send data.

I found the irq302(UART5) in the /proc/interrupt does not increase anymore during receiving data from other J6 board.

But after I change the UART5 into gpio mode on both side , I can see the data in and out on both side. Once I switch back to UART mode , the receiving issue pops again.

Do you have any idea about this ?

Best,

Andy

over 8 years ago

0 Mariya Petkova over 8 years ago

TI__Expert 4885 points

Hi, Andy,

Experts were pinged here.

Regards,
Mariya

0 Stanislav Stilyanov over 8 years ago

TI__Genius 17530 points

Andy,

Which pins are you using for UART? Rx, Tx, CTS, RTS?

Which pins you are changing to GPIO and where? Do you mean you are changing the pinmux registers? For which pins?

Can you dump the PADCONF registers for the pins in the both cases?

0 Andy Huang18 over 8 years ago in reply to Stanislav Stilyanov

Expert 1005 points

Hi Stan,
I use the CTRL_CORE_PAD_VOUT1_D0 and CTRL_CORE_PAD_VOUT1_D1 as UART5 ( mode 2) on both side , no cts and rts.
I use omapconf modify 0x4a0035dc (CTRL_CORE_PAD_VOUT1_D0) and 0x4a0035e0 (CTRL_CORE_PAD_VOUT1_D1) switch to GPIO mode directly. Ex : J6 board A only modify uart5_txd , J6 board B only modify uart5_rxd , and then use /sys/class/gpio API to test .

When the issue occurs , J6 Board A can not send data to J6 Board B.
At this time ,
J6 board A , 0x4a0035dc value is 03050002 , 0x4a0035e0 value is 00010002
J6 board B , 0x4a0035dc value is 01050002 , 0x4a0035e0 value is 00010002

Best,
Andy

0 Stanislav Stilyanov over 8 years ago in reply to Andy Huang18

TI__Genius 17530 points

Andy,
The suspicious thing is that board B is not getting wake-up event in the Pad Conf register for RX pin.
Can you please post the values of UART_SYSC (0x4806 6054) for the two boards?

Regards,
Stan

0 Andy Huang18 over 8 years ago in reply to Stanislav Stilyanov

Expert 1005 points

Hi Stan,
Both UART_SYSC value is 0xd .

Andy

0 Stanislav Stilyanov over 8 years ago in reply to Andy Huang18

TI__Genius 17530 points

Andy,
Are you using the UART to wake-up the device from low-power mode?
Your ENAWAKEUP bit is =1. However, if I remember well, IDLEMODE should be also be = 3 (allow wake-up request).

However, if you are not needing UART wake-up, or for debug, try to disable wakeup:
ENAWAKEUP =0
IDLEMODE=2
In the padconf, VOUT1_D0_WAKEUPENABLE = 0

Not sure if it will help, but I have no other recommendations up to now.

Regards,
Stan

0 Andy Huang18 over 8 years ago in reply to Stanislav Stilyanov

Expert 1005 points

Hi Stan,
Finally I soft reset UART before testing UART and then the situation disappear.
Thanks for your help.

Best,
Andy

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[J6] UART5 can not receive data