Binary Synchronous Communication (BSC) with the PCI MPQP Adapter

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The PCI MPQP adapter software performs low-level BSC frame-type determination to facilitate character parsing at the kernel-mode process level.

Frames received without errors are parsed. A message type is returned in the status field of the extension block along with a pointer to the receive buffer. The message type indicates the type of frame that was received.

For control frames that only contain control characters, the message type is returned and no data is transferred from the board. For example, if an ACK0 was received, the message type MP_ACK0 is returned in the status field of the extension block. In addition, a NULL pointer for the receive buffer is returned. If an error occurs, the error status is logged by the device driver. Unlogged buffer overrun errors are an exception.

Note: In BSC communications, the caller receives either a message type or an error status.

Read operations must be performed using the readx subroutine because the read_extension structure is needed to return BSC function results.