Motorola MVME2600 manual Asynchronous Serial Ports, Parallel Port

Block Diagram

Asynchronous Serial Ports

The two asynchronous ports provided by the ISASIO device employ TTL-level signals that are buffered through EIA-232-D drivers and receivers and routed to the P2 connector.

Hardware initializes the two serial ports as COM1 and COM2 with ISA I/O base addresses of $3F8 and $2F8 respectively. This default configuration also assigns COM1 to PIB (PCI/ISA Bridge Controller) interrupt request line IRQ4 and COM2 to IRQ3. You can change the default configuration by reprogramming the ISASIO device. For detailed programming information, refer to the PCI and ISA bus discussions in the MVME2603/2604 Programmer’s Reference Guide, listed in Appendix D, Related Documentation, and to the vendor documentation for the ISASIO device.

Parallel Port

The parallel port is a Centronics printer interface in MVME712M- compatible models, and a full IEEE1284 bidirectional parallel port in MVME761-compatible models. Both versions are implemented with the ISASIO device. All parallel I/O interface signals are routed to P2 through series damping resistors.

Hardware initializes the parallel port as PPT1 with an ISA IO base address of $3BC. This default configuration also assigns the parallel port to PIB (PCI/ISA Bridge Controller) interrupt request line IRQ7. You can change the default configuration by reprogramming the ISASIO device. For detailed programming information, refer to the PCI and ISA bus discussions in the MVME2603/2604 Programmer’s Reference Guide, listed in Appendix D, Related Documentation, and to the vendor documentation for the ISASIO device.

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