Thc Board; Control Sequence At Recording; Image Data On Main Memory; Import Of Image Data To Line Memory - FujiFilm DRYPIX 2000 Service Manual

4.4.3

THC Board

n Outline
The THC board has recording control, head resistance measurement pattern output,
and host interface functions, and is connected to the host CPU/main memory via the
PCI bus.
n Main Functions
l Interrupt
The interrupt sources are as follows.
• End of recording
• End of main memory transfer
l Reset
The head distribution data generation section is reset by the reset signal from the PCI
bus.
l Control FPGA/ Board Version Register
Enables reading of the 4 bits of the head control FPGA and board version respectively
by the version register.
016-201-04E
02.15.2007 FM5075
l Control Sequence at Recording
Generation of head distribution data by hardware can be divided into the following
three operations.
• Input of data via the PCI bus from the main memory (line memory write)
• Bitmap deployment (line memory read, intermediate data memory write)
• Transfer of serial data to head (heat generation pattern control table read,
intermediate data memory read)
l Image Data on Main Memory
The pixel format of the image data on the main memory is saved as 12 bit/pix by 16
bit boundary LSB-alignment.
l Import of Image Data to Line Memory
12 bit image data DMA-transferred via the PCI bus from the main memory by
hardware is saved in the line memory in units of lines by betaenumerate.
l Bitmap Deployment
12 bit image data in the line memory is deployed to 192 pixels x 22 bits intermediate
data for every bit weight by hardware. The respective bits of 22 bit data corresponds
to the serial signal line of the head.
As the physical data of the memory is 16 bits, taking the 22 bits of one intermediate
data after bitmap deployment to be 16 bits + 6 bits, it is saved by two memory writes.
l Heat Generation Pattern Control (Tonal Expression Method)
For each weight bit of the image data to correspond to the recording positions dividing
image pixel in the sub-scanning direction, the THC board is provided with a heat
generation pattern control table which can be set from the host.
The heat generation pattern control table corresponding to the recording position is
referred by the hardware, the designated bit weight data is read from the intermediate
data memory, and serial transfer is executed as head heat generation data.
l Recording Base Time Setting
Taking the recording time of one heat generation data (time of dividing one sub-
scanning direction pixel by the number of distributions) as the recording base time,
register setting is performed from the host.
Based on this setting time, the recording time (main-scanning period) of one sub-
scanning direction pixel is determined.
l Heat Generation Time Control
The actual time is set from the host for the logic heat generation time of heat
generation pattern control.
l Head Resistance Measurement Pattern Output Mode
The heat generation pattern for converting 1 dot of the head to the heat generation
state is output for head resistance measurement.
DRYPIX 2000 Service Manual
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MD-46