Lucent Technologies USS-720 - Manual (Page 45)

Preliminary Data Sheet, Rev. 5 USS-720 Instant USB
September 1999 USB-to- IEEE 1284 Bridge
Lucent Technologies Inc. 5-19
13
IEEE 1284 Port (continued)
ECP Command Register
Table 26. ECP Command Register
ECP Command Register Address: 5
Bit 7 6 5 4 3 2 1 0
Symbol C7 C6 C5 C4 C3 C2 C1 C0
Access Write Write Write Write Write Write Write Write
Default X X X X X X X X
Bit Symbol Bit Description
7—0 C7—C0 ECP Command. This register is equivalent to the ECP Address FIFO Register in a
standard host-side parallel port controller chip, but has some different restrictions on
its usage. The register is writable when Auto Mode is 0 and the Mode field in the
Extended Control Register is set to 011 and there is no ECP data in either the Bulk
Out buffers or in the process of being transmitted. Writes to this address in a mode
other than 011 will be ignored; writes while in mode 011 and when the hardware is
busy will generate a NAK. The value written to this register will be transferred to the
peripheral as an ECP command.