W83627UHG Nuvoton Technology Corporation of America, W83627UHG Datasheet - Page 141

• Manufacturer Part Number: W83627UHG
• Description: IC I/O CONTROLLER 128-QFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83627UHG

• Applications: PC's, PDA's
• Interface: LPC
• Voltage - Supply: 3.3V, 5V
• Package / Case: 128-XFQFN
• Mounting Type: Surface Mount
• Pin Count: 128
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

11.3.12
The host must negotiate on the parallel port to determine if the peripheral supports the ECP protocol
before ECP operation. After negotiation, it is necessary to initialize some of the port bits.
ECP address/RLE bytes or data bytes may be sent automatically by writing the ecpAFifo or ecpDFifo,
respectively.
11.3.12.1 Mode Switching
The software must handle P1284 negotiation and all operations prior to a data transfer in SPP or PS/2
modes (000 or 001). The hardware provides an automatic control line handshake, moving data
between the FIFO and the ECP port, only in the data transfer phase (mode 011 or 010).
If the port is in mode 000 or 001, it may switch to any other mode. If the port is not in mode 000 or 001,
it can only be switched into mode 000 or 001. The direction can only be changed in mode 001.
In extended forward mode, the software should wait for the FIFO to be empty before switching back to
mode 000 or 001. In ECP reverse mode, the software should wait for all the data to be read from the
FIFO before changing back to mode 000 or 001.
11.3.12.2 Command/Data
ECP mode allows the transfer of normal 8-bit data or 8-bit commands. In the forward direction, normal
data are transferred when HostAck is high, and an 8-bit command is transferred when HostAck is low.
The most significant bits of the command indicate whether it is a run-length count (for compression) or
a channel address.
In the reverse direction, normal data are transferred when PeriphAck is high, and an 8-bit command is
transferred when PeriphAck is low. The most significant bit of the command is always zero.
11.3.12.3 Data Compression
The W83627UHG hardware supports RLE decompression and can transfer compressed data to a
peripheral. Odd (RLE) compression is not supported in the hardware, however. In order to transfer
data in ECP mode, the compression count is written to ecpAFifo and the data byte is written to
ecpDFifo.
11.3.12.4 FIFO Operation
The FIFO threshold is set in CR5. All data transferred to or from the parallel port can proceed in DMA
or Programmed I/O (non-DMA) mode, as indicated by the selected mode. The FIFO is used in Parallel
Port FIFO mode or ECP Parallel Port Mode. After a reset, the FIFO is disabled.
(a) Set direction = 0, enabling the drivers.
(b) Set strobe = 0, causing the nStrobe signal to default to the deasserted state.
(c) Set autoFd = 0, causing the nAutoFd signal to default to the deasserted state.
(d) Set mode = 011 (ECP Mode)
ECP Operation
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W83627UHG