
MFC2000 Multifunctional Peripheral Controller 2000
Hardware Description
9-6
Conexant
100723A
9.1.5 First and Last Black Data Detector Design
Below is a schematic representation of the Black Data Detector. The counter and registers get cleared at the start
of each line. On the left side of the diagram is the half word counter that is incremented each time a half word is
pushed into the FIFO (lcl_nxt). When the line starts, each time a lcl_nxt or lcl_wr shifts data into the output FIFO
holding register, the serial data is checked for black data. If black data is detected, the
End Of White
flag is set.
Once set, the logic waits until the counter is incremented, (the holding register is pushed into the FIFO data
register). Then the new count value is loaded into the First Black Data Register.
As data continues to be shifted into the FIFO, the logic at the bottom of the Figure 1-2-2 continues to check for
black data. Each time black data is detected the
Blk Data Det
flag is set. After that half word is loaded into the
FIFO data register (counter counts), the counter value is loaded into the Last Black Data Register.
9.2 Register Description
External memory setup
The external memory is selected as the data source by setting bit 2 in the BiResConvCtrl register to one in
the Bi-level Resolution Conversion block.
The block size of the data in the external memory for the Bi-level resolution conversion is set in the
DMA9BlockSize register of the DMA Controller.
Vertical Line ORing for the resolution converted data is enabled by setting bit 0 in the BiResConvCtrl register
in the Bi-level Resolution Conversion block.
The Bi-level resolution conversion is initiated by setting bit 1 (first to 1 and then, to 0) in the BiResConvCtrl
register in the Bi-level Resolution Conversion block.
T4/T6 Control
T4/T6 Decoder Bi-level resolution conversion is enabled by setting bit 5 in the ‘T4Config’ register in the T4/T6
Compression/Decompression Logic.
Vertical Line ORing for the T4 Decoded data is enabled by setting bit 3 in the ‘T4Control’ register in the T4/T6
Compression/Decompression Logic. Vertical ORing for T4 decoded data is only valid if resolution conversion
is also enabled.
Programming the Expansion/reduction Ratio
The Bi-level Resolution Conversion Ratio register (BiResConRatio) controls the horizontal resolution conversion
expansion or reduction ratio. The BiResConRatio register is cleared on Reset. The value programmed into the
register is the number of pixels to add or remove per 2187 pixels (expressed as a 7 digit base-3 number).