D7225G NEC, D7225G Datasheet - Page 8

• Manufacturer Part Number: D7225G
• Description: Search -----> UPD7225G
• Manufacturer: NEC

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2.
2.1 Serial Interface
counter increments (+1) the serial clock. As a result, if an overflow occurs (when eight pulses are counted), input
from the SI pin is disabled (/BUSY = 0), and the contents of the serial register is output to the command/data register.
input to /SCK).
2.2 Command/Data Register
into the serial register.
command/data register transfers its contents to the command decoder. If specified as data the command/data
register transfers its contents to data memory or the segment decoder.
2.3 Command Decoder
input), the command decoder, clocks in the contents of the command/data register and controls the PD7225.
2.4 Segment Decoders
decoder for use divide-by-4 time division.
segment decoder can generate signals for 36 alphanumeric characters and 13 different symbols. When the WITH
SEGMENT DECODER command is executed, if the contents of the command/data register are specified as data, the
contents will be input to the segment decoder, and converted to display codes, and then automatically written to the
data memory.
significant bit (bit 7) of the data input to the segment decoder. It the most significant bit is 0, the 7-segment decoder
will be selected. If it is 1, the 14-segment decoder will be selected. If the 7-segment decoder is selected (however,
divide-by-3 and divide-by-4 time division), the lower 4 bits (bit 3 to bit 0) of the input data (C, /D = 0) will be decoded
and written to the data memory.
= 0) will be decoded and written to the data memory.
8
The serial interface consists of an 8-bit serial register and a 3-bit SCK counter.
The serial register clocks in the serial data from the SI pin at the rising edge of /SCK. At the same time, the SCK
The /SCK should be set to high before serial data is input and after the data has been input (after eight clocks are
Serial data must be input to the SI pin beginning with MSB first.
The command/data register latches the contents of the serial register in order to process the serial data clocked
When the contents of the command/data register are specified as a command (C, /D was high when data was
The PD7225 has a 7-segment decoder for use with divide-by-3 and divide-by-4 time division, and a 14-segment
The 7-segment decoder can generate signals for numeric characters 0 to 9 and six different symbols. The 14-
If the 14- segment decoder is selected (however, divide-by-4 time division), the lower 7 bits of the input data (C, /D
INTERNAL SYSTEM CONFIGURATION
Whether to select the 7-segment decoder or 14-segment decoder is determined by the most
PD7225
After the serial data is latched, if the clocked in data is specified as command, the
SI pin
MSB
D7
Data Sheet S14308EJ6V0DS00
D6
D5
D4
D3
D2
D1
LSB
D0
PD7225