W90221X Winbond Electronics Corp America, W90221X Datasheet - Page 35

• Manufacturer Part Number: W90221X
• Description: Pa-risc Embedded Controller
• Manufacturer: Winbond Electronics Corp America

As for 4-word code ROM burst read, the timing diagram is similar to Fig5.8.4 except there
will be consecutive 16 C/BE0## (WRD#) command pulses within one chip select (INTD#,
C/BE2##).
5.11 PARALLEL PORT INTERFACE
5.11.1 Features
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5.11.2 Related Pins
All 17 PPI interface signals share pins with GPIOs. When T_ENECP (port 0xf000003e, bit 4)
is set, the corresponding GPIOs are redefined as follows:
GPIO[16]/nStrobe (output)
GPIO[15]/nAutoFd (output)
GPIO[8]/nInit (output)
W90221X version 0.6
Supports all IEEE P1284 transfer modes including:
Host-side design
Provide a special operation mode to emulate peripheral-side Centronic device
Build-in one 16bytes FIFO to accelerate ECP mode and Centronic forward transfer
Provide DMA capability to accelerate moving data from parallel port interface to system
memory
ECP mode is also including:
Compatible Mode: Set active low to transfer data into peripheral device's input latch
ECP Mode:
Compatible Mode:Set low by host to put some printers into auto-line feed mode. May
ECP Mode:
Compatible Mode:Pulsed low in conjunction with "nSelectIn" active low to reset the
ECP Mode:
Compatible (Centronic) mode (forward channel)
Nibble mode (reverse channel, compatible with all existing PC hosts - relies on
software control)
Byte mode (reverse channel, compatible with IBM PS/2 host)
EPP mode (bi-directional half-duplex channel - relies on software control)
ECP mode (fast bi-directional half-duplex channel)
High performance half-duplex forward and reverse channel
Interlocked handshake, for fast reliable transfer
Forward "channel-addressing/command transfer" for low-cost peripherals
Support reverse RLE decompression
Peer-to-peer capability
Used in a closed-loop handshake with "Busy" to transfer data or
address information from host to peripheral device.
also be used as a ninth data, parity, or command/data control bit.
The host drives this signal for flow control in the reverse direction. It is used
in an interlocked handshake with "nAck". "nAutoFd" also provides a ninth
data bit used to determine whether command or data information is present
on the data signals in the forward transferring.
interface and force a return to compatible mode idle state.
This signal is driven low to place the channel in the reverse direction.
While in this mode, the peripheral is only allowed to drive the bi-
directional data signals when "nInit" is low and "nSelectIn" is high.
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