MN5572 Datasheet, PDF (20/28 Pages) Panasonic Semiconductor – Gray Scale Font Engine

MN5572
I Operation
2. Operating Procedures (continued)
2. 4. Gray-scale data readout processing
• Gray-scale data readout processing flowchart
start
Status register check
(status read)
RMS, REC, RVS
RMS verification
EMPTY RMS
FULL or READY
Gray-scale data readout
RVS
(up to 64 double words)
11 : FULL
01 : READY
00 : EMPTY
00h(1 double-word) to
3Fh(64 double-word)
Has 1 frame completed?
REC = 1
end
REC = 0
• Gray-scale data readout processing flowchart description
This operation reads out the gray-scale data created by the IC.
• Status register check
The status register is read and checked.
• RMS verification
The operation performed will be determined by the value of the status register RMS field.
If the RMS field indicates that the FIFO is empty, it means that the IC has not yet completed generation of the
gray-scale data and the status register must be checked again after a wait.
If the RMS field indicates ready, a read operation can be started.
If the RMS field indicates full, the IC will have to interrupt its gray-scale data generation processing. Therefore,
the available data should be read out as quickly as possible.
• Gray-scale data readout
The multi-valued gray-scale data for a single figure or font character is output from the IC gray-scale data
output port (RASTER FIFO).
The maximum amount of gray-scale data that can be output at a time is 64 double words. The amount of
gray-scale data that can actually be output is indicated by RVS. If the amount of gray-scale data to be output
exceeds 64 double words, the data will be broken up into 64 double words units and processed internally.
If the REC field in the status register is 1, the multi-valued gray-scale data for a single figure or font character
can be completely read out by reading out the amount of data indicated by RVS.
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