NdisImmediateReadPortUchar

This function is obsolete for Windows XP and later. Windows XP supports this function for legacy drivers; however, the Windows XP DDK will not build an NDIS driver that calls this function. Drivers should call NdisReadPortUchar instead.

NdisImmediateReadPortUchar reads a byte from a given bus-relative I/O port.

VOID
  NdisImmediateReadPortUchar(
    IN NDIS_HANDLE  WrapperConfigurationContext,
    IN ULONG  Port,
    OUT PUCHAR  Data
    );

Parameters

WrapperConfigurationContext

Specifies the handle input to MiniportInitialize.

Port

Specifies the bus-relative I/O port address.

Data

Pointer to a caller-supplied variable in which this function returns the value read from the I/O port.

Headers

Declared in Ndis.h. Include Ndis.h.

Comments

NdisImmediateReadPortUchar determines how the host accesses the given I/O port, maps the bus-relative port address, and then reads a byte from the device.

A miniport driver can call NdisImmediateReadPortUchar during initialization to read data from a device I/O port when that driver has not yet called NdisMRegisterIoPortRange to obtain mapped device memory ranges. After its call to NdisMRegisterIoPortRange, the driver uses the faster NdisRawXxx functions to communicate with its NIC.

A miniport driver should not call NdisImmediateReadPortUchar in a Plug and Play environment.

Callers of NdisImmediateReadPortUchar run at IRQL = PASSIVE_LEVEL.

See Also

MiniportInitialize, NdisImmediateReadPortUlong, NdisImmediateReadPortUshort, NdisImmediateWritePortUchar, NdisMRegisterIoPortRange, NdisRawReadPortUchar NdisReadPortUchar