usif.c File Reference

#include "common.h"

Macros
#define	USIF_FIFO_STAT   0x00000044
#define	USIF_FIFO_STAT_TXFFS   0x00FF0000
#define	USIF_FIFO_STAT_RXFFS   0x000000FF
#define	USIF_TXD   0x00040000
#define	USIF_RXD   0x00080000

Functions
BOOLEAN	UsifInitializePort (_In_opt_ _Null_terminated_ PCHAR LoadOptions, _Inout_ PCPPORT Port, BOOLEAN MemoryMapped, UCHAR AccessSize, UCHAR BitWidth)
BOOLEAN	UsifSetBaud (_Inout_ PCPPORT Port, ULONG Rate)
UART_STATUS	UsifGetByte (_Inout_ PCPPORT Port, _Out_ PUCHAR Byte)
UART_STATUS	UsifPutByte (_Inout_ PCPPORT Port, UCHAR Byte, BOOLEAN BusyWait)
BOOLEAN	UsifRxReady (_Inout_ PCPPORT Port)

Macro Definition Documentation

USIF_FIFO_STAT

#define USIF_FIFO_STAT   0x00000044

USIF_FIFO_STAT_RXFFS

#define USIF_FIFO_STAT_RXFFS   0x000000FF

USIF_FIFO_STAT_TXFFS

#define USIF_FIFO_STAT_TXFFS   0x00FF0000

USIF_RXD

#define USIF_RXD   0x00080000

USIF_TXD

#define USIF_TXD   0x00040000

Function Documentation

UsifGetByte()

UART_STATUS UsifGetByte	(	_Inout_ PCPPORT	Port,
		_Out_ PUCHAR	Byte )

{
    ULONG Stat;
    ULONG Value;
 
    *Byte = 0;
 
    if ((Port == NULL) || (Port->Address == NULL))
    {
        return UartNotReady;
    }
 
    //
    // Get FIFO status.
    //
 
    Stat = READ_REGISTER_ULONG((PULONG)(Port->Address + USIF_FIFO_STAT));
 
    //
    // Is at least one character available?
    //
 
    if ((Stat & USIF_FIFO_STAT_RXFFS) != 0)
    {
        //
        // Fetch the data byte.
        //
 
        Value = READ_REGISTER_ULONG((PULONG)(Port->Address + USIF_RXD));
        *Byte = Value & (UCHAR)0xFF;
        return UartSuccess;
    }
 
    return UartNoData;
}

UsifInitializePort()

BOOLEAN UsifInitializePort	(	_In_opt_ _Null_terminated_ PCHAR	LoadOptions,
		_Inout_ PCPPORT	Port,
		BOOLEAN	MemoryMapped,
		UCHAR	AccessSize,
		UCHAR	BitWidth )

{
    UNREFERENCED_PARAMETER(LoadOptions);
    UNREFERENCED_PARAMETER(AccessSize);
    UNREFERENCED_PARAMETER(BitWidth);
 
    if (MemoryMapped == FALSE)
    {
        return FALSE;
    }
 
    Port->Flags = 0;
    return TRUE;
}

UsifPutByte()

UART_STATUS UsifPutByte	(	_Inout_ PCPPORT	Port,
		UCHAR	Byte,
		BOOLEAN	BusyWait )

{
    if ((Port == NULL) || (Port->Address == NULL))
    {
        return UartNotReady;
    }
 
    //
    // Wait for port to be free and FIFO not full.
    //
 
    if (BusyWait != FALSE)
    {
        while (READ_REGISTER_ULONG((PULONG)(Port->Address + USIF_FIFO_STAT)) &
               (USIF_FIFO_STAT_TXFFS))
            ;
    }
    else if (READ_REGISTER_ULONG((PULONG)(Port->Address + USIF_FIFO_STAT)) &
             (USIF_FIFO_STAT_TXFFS))
    {
        return UartNotReady;
    }
 
    //
    // Send the byte.
    //
 
    WRITE_REGISTER_ULONG((PULONG)(Port->Address + USIF_TXD), (ULONG)Byte);
    return UartSuccess;
}

UsifRxReady()

BOOLEAN UsifRxReady

(

_Inout_ PCPPORT

Port

)

{
    ULONG Stat;
 
    if ((Port == NULL) || (Port->Address == NULL))
    {
        return FALSE;
    }
 
    //
    // Read the STAT Register to determine if there is any pending
    // data to read.
    //
 
    Stat = READ_REGISTER_ULONG((PULONG)(Port->Address + USIF_FIFO_STAT));
    if ((Stat & USIF_FIFO_STAT_RXFFS) != 0)
    {
        return TRUE;
    }
 
    return FALSE;
}

UsifSetBaud()

BOOLEAN UsifSetBaud	(	_Inout_ PCPPORT	Port,
		ULONG	Rate )

{
    if ((Port == NULL) || (Port->Address == NULL))
    {
        return FALSE;
    }
 
    //
    // Remember the baud rate.
    //
 
    Port->BaudRate = Rate;
    return TRUE;
}