D7225G NEC, D7225G Datasheet - Page 14

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

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2.5 Data Memory/Data Pointer
immediate data, etc., is written to the data memory.
segment decoder (when the segment decoder is used) is written as display data.
register are assigned and written to the specific bits in location 2 to location 4 in the data memory according to the
specified time division. When the segment decoder is used, the contents of the serial register (C, /D = 0) are
decoded by the segment decoder, and the corresponding display data are allocated to the location specified in data
memory by the time division specification (devide-by-3, -4 time division) and the MSB (Most Significant Bit) of the
serial data. (1) to (4) below describe these operations.
14
(1) Static
(2) Divide-by-2 time division
The data memory is a memory which stores display data (32
In the data memory, either data from the serial register (when the segment decoder is not used) or data from the
When the segment decoder is not used, all bits or the lower 4 bits of the serial data (C, /D = 0) input to the serial
The contents of the data memory can be modified in 4-bit units or in bit units using a command.
The lower 4 bits of the contents of the serial register are written to bit 0 in each address (the upper 4 bits are
ignored).
Only the content of bit 0 in each address are effective as display data.
After the data is written, the data pointer points to address n + 4.
The contents of the 4 even bits of the serial register are written to bit 0 in the four addresses, and the contents
of 4 odd bits of the serial register are written to bit 1.
The contents of bits 0 and 1 of each address are effective as display data.
After the data is written, the data pointer points to address n + 4.
n + 3
n + 3
Bit
D7 D6
D3
0
1
2
3
0
Specified by data pointer
1
2
n + 2
n + 2
Data Sheet S14308EJ6V0DS00
3
D5 D4
4
D2
5
6
Address
7
8
n + 1
n + 1
4 bits). Data input by serial transfer, command
9 10
D3 D2
D1
bit3
bit3
29 30 31
Address n
Address n
D1 D0
D0
bit0
bit0
PD7225