Chapter 5 Input/Output Interfaces
5.5.2 ENHANCED PARALLEL PORT MODE
In Enhanced Parallel Port (EPP) mode, increased data transfers are possible (up to 2 MB/s) due to a hardware protocol that provides automatic address and strobe generation. EPP revisions 1.7 and
1.9are both supported. For the parallel interface to be initialized for EPP mode, a negotiation phase is entered to detect whether or not the connected peripheral is compatible with EPP mode. If compatible, then EPP mode can be used. In EPP mode, system timing is closely coupled to EPP timing. A watchdog timer is used to prevent system lockup.
Five additional registers are available in EPP mode to handle 16- and
5.5.3 EXTENDED CAPABILITIES PORT MODE
The Extended Capabilities Port (ECP) mode, like EPP, also uses a hardware
Ten control registers are available in ECP mode to handle transfer operations. In accessing the control registers, the base address is determined by address lines
The ECP mode includes several
Second Edition – April 2003