SerCx2 I/O Transactions
SerCx2 simplifies the handling of read (IRP_MJ_READ) and write (IRP_MJ_WRITE) requests for your serial controller driver. In response to a read or write request, SerCx2 issues one or more I/O transactions to the serial controller driver. From the driver's point of view, each transaction is a simple and complete I/O operation.
In this section
| Topic | Description |
|---|---|
SerCx2 handles a read or write request from a client by issuing one or more I/O transactions to the serial controller driver. This driver treats each transaction as a self-contained I/O operation that transfers data between the serial controller and the data buffer in the request. |
|
SerCx2 requires all serial controller drivers to implement support for receive transactions that use programmed I/O (PIO). To start a PIO-receive transaction, SerCx2 calls the driver's EvtSerCx2PioReceiveReadBuffer event callback function and supplies a read buffer as a parameter. |
|
SerCx2 requires all serial controller drivers to implement support for transmit transactions that use programmed I/O (PIO). To start a PIO-transmit transaction, SerCx2 calls the driver's EvtSerCx2PioTransmitWriteBuffer event callback function and supplies a write buffer as a parameter. |
|
Some serial controller drivers implement support for receive transactions that use the system DMA controller. Such support is optional but can improve performance by relieving the main processor of the need to use programmed I/O (PIO) for long data transfers. |
|
Some serial controller drivers implement support for transmit transactions that use the system DMA controller. Such support is optional but can improve performance by relieving the main processor of the need to use programmed I/O (PIO) for long data transfers. |
|
Some serial controller hardware might implement a data-transfer mechanism other than PIO or system DMA for reading data from a serial controller. A serial controller driver can support custom-receive transactions to make this data-transfer mechanism available to be used by SerCx2. |
|
Some serial controller hardware might implement a data-transfer mechanism other than PIO or system DMA for writing data to a serial controller. A serial controller driver can support custom-transmit transactions to make this data-transfer mechanism available to be used by SerCx2. |