If the CTS signal drops before the frame transmission is complete, the frame is discarded and the abort error statistic is incremented. If the transmission underruns, an abort sequence is not sent and the frame is silently discarded. The RTS signal remains asserted until the data transmission is complete.
IBM Half-Duplex Mode
Half-duplex is a submode of the IBM mode (mode=ibm-hdx). Half-duplex mode operates in the same manner as full-duplex mode except that transmission cannot occur while receiving, and vice-versa. When a transmission is completed, the RTS signal is dropped. Dropping the RTS signal tells the remote station to begin transmitting if it is ready to.
IBM MultiPoint Mode
In a multipoint configuration (mode=ibm-mpt), more than two stations share a link. This configuration is accomplished by designating one station as a primary station and the rest as secondary stations. In this mode, the port acts as a secondary station. The primary station arbitrates traffic on the link by polling the secondary stations, to see if they are ready to transmit.
If a secondary station has data to transmit, it will raise its RTS signal and check for CTS signals. When a CTS signal comes up the station may begin transmitting, following the same rules for RTS and CTS signals used in half-duplex mode. When the transmission is complete the secondary drops the RTS signal, which enables another station to respond to a poll and begin transmitting. The RTS signal cannot be dropped until the transmission is complete.
hsip_loop Utility
The hsip_loop utility is high-speed, synchronous, serial loopback test program for high-speed serial interface. The utility performs several loopback tests that exercise the components of a serial communications link. See the hsip_loop(1M) man page for more information.
20 Sun PCI High Speed Quad Port Serial Interface Adapter User’s Guide • December 2005