PN7462AU HSU UART – Is RTS/CTS Hardware Flow Control Enabled by Default

uday_gowda — Fri, 22 May 2026 12:36:51 GMT

Hello Team,

I am working with PN7462AU, using HSU UART through HIF initialization. I would like to clarify whether RTS/CTS hardware flow control is enabled by default when using HSU UART on PN7462.

I am not explicitly enabling hardware flow control in firmware. However, I observed that UART transmission appears to depend on the CTS line state, and I would like to understand whether HSU/HIF internally enables or depends on RTS/CTS by default.

Questions:

Is RTS/CTS hardware flow control enabled by default for HSU when phhalHif_Init() is called with E_HIF_HSU?
Does phhalHif_Init() or HSU internally configure TX to wait for CTS?
If flow control is enabled by default, how can it be disabled completely?
Are there specific APIs or registers to disable RTS/CTS dependency?

My current HSU initialization is:

void Hif_UartInit(void)
{
    gHifConfig.eInterface = E_HIF_HSU;

    gHifConfig.sConfig.sHsuConfig.bIsHsuBoot  = 0;
    gHifConfig.sConfig.sHsuConfig.bBaudRate   = E_HSU_BAUDRATE_115_2K;
    gHifConfig.sConfig.sHsuConfig.bStopBits   = 1;
    gHifConfig.sConfig.sHsuConfig.bDummyBytes = 0;
    gHifConfig.sConfig.sHsuConfig.bEOF        = 32;

    gHifConfig.bTimeout       = 0;
    gHifConfig.eBufferType    = E_BUFFER_FORMAT_FREE;
    gHifConfig.bShortFrameLen = 0;
    gHifConfig.bStoreErrData  = 0;
    gHifConfig.bHeaderSize    = 0;

    phhalHif_Init(...);

    phhalHif_InitRxBuffer(...);
}

Any clarification would be helpful.

Thanks.

Re: PN7462AU HSU UART – Is RTS/CTS Hardware Flow Control Enabled by Default

EduardoZamora — Fri, 22 May 2026 19:40:50 GMT

Hello @uday_gowda

The host interface will sample the value of CTS before sending a byte; CTS must be in valid state for TX to proceed.

Perhaps you can try to "bypass" it by driving it to a fixed ready state. You could consider pulling CTS to the active state by using an external resistor.

Regards,
Eduardo.

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PN7462AU HSU UART – Is RTS/CTS Hardware Flow Control Enabled by Default

Re: PN7462AU HSU UART – Is RTS/CTS Hardware Flow Control Enabled by Default