28478-DSH-002-E Datasheet, PDF (163/195 Pages) M/A-COM Technology Solutions, Inc. – Multichannel Synchronous Communications

Basic Operation
Effects:
• The Interrupt Descriptor in Interrupt Queue with ERROR = ONR, DIR = 1.
• Data from Data Buffer not being read.
• The Buffer Descriptor not overwriting the Buffer Status Descriptor.
• No additional activity on the PCI bus for this channel direction.
• Transmit channel activity is suspended.
Channel Level Recovery Actions:
• Provide sufficient amount of data for transmission using lists of Message Descriptors with ownership given to
MUSYCC.
• Reactivate transmit channel.
6.4.9.3.2
Underflow Due to Internal FIFO Buffer Under-Run (BUFF)
In the case of underflow due to internal FIFO buffer under-run (BUFF), the internal FIFO buffer becomes empty
when MUSYCC must output data bits (at the serial interface clock rate) and MUSYCC has ownership of a message
buffer in shared memory.
Reasons:
• Degradation of the host subsystem or application software performance.
• Congestion of the PCI bus.
Effects:
• MUSYCC writes the Interrupt Descriptor in Interrupt Queue with ERROR = BUFF, DIR = 1.
• Continuous idle code transmission.
• Data from data buffer not being read.
• The Buffer Descriptor not overwriting the Buffer Status Descriptor.
• No additional activity on the PCI bus for this channel direction.
• Transmit channel activity is suspended.
Channel Level Recovery Actions:
• Provide sufficient amount of data for transmission using lists of Message Descriptors with ownership given to
MUSYCC.
• Reactivate transmit channel.
6.4.9.4
Receive Errors
Receive errors are service-affecting and may require a corrective action by a controlling device to resume normal
bit-level processing.
6.4.9.4.1
Overflow Due to Host Ownership of the Buffer (ONR)
In the case of overflow due to host ownership of the buffer, the host has not provided sufficient data buffer space to
store received data from the serial interface, and the internal FIFO buffer overflows with received data bits.
Reasons:
• Degradation of the host subsystem or application software performance.
28478-DSH-002-E
Mindspeed Technologies^®
150
Preliminary Information / Mindspeed Proprietary and Confidential