I2C to UART SC16IS750 is not working

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I2C to UART SC16IS750 is not working

516 Views
JarvisC
Contributor II

Hello,

 

I'm using NXP-SC16IS750 as I2C to UART bridge in Linux embedded board with kernel 4.4.120, but both of the RS232 /RS485 are not working.

 

Attach is the SC16IS7xx driver that we used.

 

The /dev/ttySC0 shows up after modifying the DTS to fit our hardware design.

The test result fails when an X86 PC connects to this embedded board (w/ SCI16IS750).

The test result is okay if the X86 PC connects to another board.

 

The scope connects to the PC side, which shows the DB9 TX pin has the signal when the PC side sends some characters.

No signal shows up on DB9 TX and RX pins, when this embedded board sents some characters.

 

 

Is there specific item that we need to implement or which driver should we used to implement the function of SC16IS750 bridge?

 

 

DTS

i2c@11000 {

    pinctrl-names = "default";

    pinctrl-0 = <&i2c0_pins>;

    status = "okay";

    clock-frequency = <100000>;

    sc16is750: sc16is750@48 {

        compatible = "nxp,sc16is750";

        interrupts-extended = <&gpio0 11 8>;

        clocks = <&coreclk 0>;

        gpio-controller;

        #gpio-cells = <2>;

        interrupt-controller;

        #interrupt-cells = <2>;

        reg = <0x48>;

    };

};

 

 

Thanks.

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7 Replies

63 Views
Ssystems
Contributor I

Hi both,

Any news on the driver provided by JozefKozon? I'm experiencing issues with the Linux included driver (kernel 5.4.148)
sc16is7xx.c - drivers/tty/serial/sc16is7xx.c - Linux source code (v5.4.148) - Bootlin

The driver seems to build successfully and I'm able to read/write registers to the sc16is750 with "i2cget/i2cset" commands but the driver doesn't take over the device

Ssystems_0-1658992658910.png

Ssystems_1-1658992696706.png

Tried this

Ssystems_3-1658992826187.png

And this in the DTS

Ssystems_4-1658992865359.png

 

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515 Views
JarvisC
Contributor II

Hello,

Should we set the IRQ of SC16IS750 bridge?

If yes, what should we do?

Thanks

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508 Views
JozefKozon
NXP TechSupport
NXP TechSupport

Hello Jarvis,

please test the Linux driver attached. Please share your schematic with voltage levels and part values to check it.

With Best Regards,

Jozef

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371 Views
JarvisC
Contributor II

Dear Jozef,

Could you help to upload the linux driver again?

Thanks.

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481 Views
JarvisC
Contributor II

Dear Jozef,

After downloaded  "SC16IS750_Linux .zip" , that could not be extracted successful.

There should be some problem of the attach file.

Could you help to upload it again?

Thanks.

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366 Views
JozefKozon
NXP TechSupport
NXP TechSupport

Dear Jarvis,

I apologize for a late reply. 

I have downloaded another SC16S750 from different source. This one should work. Please find it attached.

With Best Regards,

Jozef

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26 Views
JozefKozon
NXP TechSupport
NXP TechSupport

Hi All,

please see below an answer from an application engineer regarding the Linux driver for SC16IS750. 

I apologize for inconvenience.

DESCRIPTION

We do not provide any support for the Linux driver since we don’t have a software engineer. Years ago we offered a Linux driver for kernel as reference. The customer could use the driver as is, as their own risk. We did not offer any software support and it is still the same.

With Best Regards,

Jozef

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