
MFC2000 Multifunctional Peripheral Controller 2000
Hardware Description
14-4
Conexant
100723A
Address
Bit 15
(Not Used)
Bit 14
(Not Used)
Bit 13
(Not Used)
Bit 12
(Not Used)
Bit 11
(Not Used)
Bit 10
(Not Used)
Bit 9
Bit 8
Default
Rst. Value
xxh
Read Value:
00h
T4 Control
(T4Control)
$01FF8173
(Not Used)
(Not Used)
Address
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default
Rst. Value
x0000000b
Read Value
00h
T4 Control
(T4Control)
$01FF8172
Reset T4
Block (w)
Terminating
Code Error
Enable Bi-
level
Resolution
Conversion
Decode
Output
Enable
Vertical OR
enable
(decompress
mode only)
Reset/Halt
Coding or
decoding
Start coding
or decoding
Flush CW
(completes
byte)
Bit 15-8:
Bit 7:
Not used
Writing a 1 to this bit causes the T4 logic to be reset, including all
internal state machines and FIFOs. This bit is useful when switching
between compression and decompression modes.
A Terminating Code Error is indicated when a
run length = 0
code is
expected but not received at the end of a line, and the Terminating
Code Error also sets the Line error bit
Enable Bi-level Resolution Conversion.
Bit 6:
Bit 5:
Bi-level resolution conversion is only valid in decompression mode.
When this bit is set, horizontal resolution conversion will be performed
on the decoder output. Both the unconverted line and the converted
line will be output to the line buffer. The converted line will be written
to the line buffer via DMA channel 8.
Decode Output Enable allows decoded data to be output to the line
buffers. This bit should not be set in MH or MR decoding until the first
EOL has been found. The decoder output should also be disabled
after an error line until the next EOL is found. This bit should always
be set for the MMR decoder.
The Vertical OR bit is only valid in decompression mode when the bi-
level resolution conversion bit in the T4Config register is also set.
When the Vertical OR bit is set, the resolution converted decoded
output data is ORed with the corresponding byte from the previous line
before storing.
Reset or halt the coding or decoding.
Bit 4:
Decode output enable.
Bit 3:
Vertical OR enable.
Bit 2:
Setting the Reset/Halt bit immediately halts coding or decoding of a
line, resets all the T4 Status bits, and clears the active T4Data FIFO.
All other bits in this register are ignored if the Reset/Halt bit is set.
When coding or decoding is in progress, writing to any bit in this
register except Reset/Halt is ignored.
The Start bit begins the coding or decoding of the line according to the
configuration selected per the T4Config register.
Bit 1:
Start coding or decoding.