
=
The above information is the exclusive intellectual property of Winbond Electronics and shall not be disclosed, distributed or reproduced without permission from Winbond.
28
Versi on 0. 4, March/2000
flexible block-transfer mode and demand mode are supported
provides 8-bit ecp-to-memory or memory-to-ecp transfer mode
provides 8-, 16- and 32-bit memory-to-memory transfer modes
DMA transfer between PCI memory to/from system memory are also support
4 words (16 bytes) memory burst-access; linear burst order
build-in 4-words data FIFO to accelerate memory access
the starting address of source and target shall be halfword boundary for 16-bit memory transfer and word
boundary for 32-bit memory transfer
Related Pins :
None
Operation Modes :
(Left for Blank)
5.7 PCI BRIDGE
Overview :
The W90221 host bridge provides a PCI bus interface that is compliant with the PCI local bus
specification, revision 2.1, the implementation is optimized for high performance data streaming
when the W90221 is acting as either the target or the initiator on the PCI bus.
Block Diagram :
(Left for Blank)
Features :
Supports up to 4 external PCI bus master.
Flexible programming external PCICLK delay reference to internal EXTCLK.
Provides fix/rotate priority abitration.
Provides configuration read/write, I/O read/write, memory read/write access.
Related Pins :
- PCLK (in) :
PCLK provides timing for all transactions on PCI and is an input to every PCI device.
- FRAME# (inout) :
FRAME# is an output when W90221 acts as an initiator on the PCI bus, FRAME# is asserted
to indicate a bus transaction is beginning. While FRAME# is asserted, data transfer
continue.
When FRAME# is deasserted, the transaction is in the final data phase or has completed.
FRAME# is an input when W90221 acts as a PCI target.
- PDA[31:0] (inout) :
These signals are connected to the PCI address/data bus. Address is driven by W90221 with
FRAME# is asserted, data is driven or received in the following clocks. when W90221 acts
as a target on the PCI bus, the AD[31:0] signals are inputs and contain the address during the
first clock of FRAME# assertion and input data(writes) or output data(reads) on sebsequent
clocks.
- COMBE#[3:0] (inout) :