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Question about Omega-2+ pins?



  • When I entered the command omega2-ctrl gpiomux get, I seen it:

    Group i2c - [i2c] gpio
    Group uart0 - [uart] gpio
    Group uart1 - [uart] gpio pwm01
    Group uart2 - [uart] gpio pwm23
    Group pwm0 - pwm [gpio]
    Group pwm1 - pwm [gpio]
    Group refclk - refclk [gpio]
    Group spi_s - spi_s [gpio] pwm01_uart2
    Group spi_cs1 - [spi_cs1] gpio refclk
    Group i2s - i2s [gpio] pcm
    Group ephy - [ephy] gpio
    Group wled - wled [gpio]
    

    I have several question about Omega-2+ pins.

    1. Omega 2+ has three UART? I know about UART0 and UART1, but what pins support UART2?
    2. What pins support PWM and how to use them? (Is it possible to connect the servo motor?)
    3. What is it Group refclk, Group ephy and Group wled?


  • @CAP-33 said in Question about Omega-2+ pins?:

    1. Omega 2+ has three UART? I know about UART0 and UART1, but what pins support UART2?

    omega2-ctrl gpiomux set spi_s pwm01_uart2
    Omega2(+)'s UART2 (ttyS2) works well using GPIO16 as TX2 and GPIO17 as RX2 (8N1 default BAUD rate 9600 bps).

    # Omega2+ FW v0.2.2 b201
    
    root@Omega-5BE1:~# omega2-ctrl gpiomux set spi_s pwm01_uart2
    set gpiomux spi_s -> pwm01_uart2
    
    root@Omega-5BE1:~# omega2-ctrl gpiomux get
    Group i2c - [i2c] gpio 
    Group uart0 - [uart] gpio 
    Group uart1 - [uart] gpio pwm01 
    Group uart2 - [uart] gpio pwm23 
    Group pwm0 - pwm [gpio] 
    Group pwm1 - pwm [gpio] 
    Group refclk - refclk [gpio] 
    Group spi_s - spi_s gpio [pwm01_uart2] 
    Group spi_cs1 - [spi_cs1] gpio refclk 
    Group i2s - i2s [gpio] pcm 
    Group ephy - [ephy] gpio 
    Group wled - wled [gpio]
    

    I don't have Omega2(+)S so I can't try the other setting:
    omega2-ctrl gpiomux set uart2 uart

    Details: enable uart2 is posiible on Omega2+??



  • @György-Farkas
    Thank you.
    Can you answer the second and third questions?



  • Have a look at these annotated pinouts for Omega2(+/S) for seeing all possible pin functions.

    1. Omega 2+ has three UART? I know about UART0 and UART1, but what pins support UART2?

    @CAP-33 as @György-Farkas said, the answer to question 1 is GPIO16/17 for UART_TXD2/UART_RXD2, when you switch the GPIO multiplexer with omega2-ctrl gpiomux set spi_s pwm01_uart2

    1. What pins support PWM and how to use them? (Is it possible to connect the servo motor?)

    On the Omega2(+), only two (of the chip's total of 4) PWMs can be used. On the Omega2S you have all four.

    There are three options for exposing PWMs:

    • As pwm01_uart2 in the answer to question 1 suggests, using that statement not only enables UART2, but also exposes PWM0/1 to the other two SPI slave pins GPIO14 and 15. Of these, only GPIO14 and hence PWM0 is available in the Omega2(+)
    • Using omega2-ctrl gpiomux set uart1 pwm01 you can expose PWM0/1 to pins GPIO45/46, resp.
    • Finally you can enable PWM0/1 individually on pins GPIO18/19 with omega2-ctrl gpiomux set pwm0 pwm and omega2-ctrl gpiomux set pwm1 pwm

    You can use the PWMs for anything that needs PWM, including servo motors. The MT7688 PWMs are very precise, it has 32bit range with a maximum resolution of 25nS.

    1. What is it Group refclk, Group ephy and Group wled?
    • Group refclk affects thg refclk pin (GPIO or clock)
    • ephy should be named eled and can enable Ethernet activity LED output on GPIO43 (only Omega2S)
    • wledcan enable WiFi activity LED output on GPIO44 (again, only Omega2S)


  • @luz
    Thank you very much!


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