PT6955_10 Datasheet, PDF (5/19 Pages) Princeton Technology Corp – LED Driver IC

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LED Driver IC
PT6955
FUNCTION DESCRIPTION
COMMANDS
A command is the first byte (b0 to b7) inputted to PT6955 via the DIN Pin after STB Pin has changed
from “HIGH” to “LOW” State. If for some reason the STB Pin is set to “HIGH” while data or commands
are being transmitted, the serial communication is initialized, and the data/commands being
transmitted are considered invalid.
COMMAND 1: DISPLAY MODE SETTING COMMANDS
PT6955 provides 4 display mode settings as shown in the diagram below: As stated earlier a command
is the first one byte (b0 to b7) transmitted to PT6955 via the DIN Pin when STB is “LOW”. However, for
these commands, Bit No. 3 to Bit No.6 (b2 to b5) are ignored, Bit No.7 & Bit No.8 (b6 to b7) are given
a value of “0”.
The Display Mode Setting Commands determine the number of segments and grids to be used (1/4 to
1/7 duty, 12 to 9 segments). When these commands are executed, the display is forcibly turned off.
A display command “ON” must be executed in order to resume display. If the same mode setting is
selected, no command execution is take place, therefore, nothing happens.
When Power is turned “ON”, the 7-Grid, 9-Segment Mode is selected.
MSB
LSB
0 0 - - - - b1 b0
Not Relevant
Display Mode Settings:
00: 4 digits, 12 segments
01: 5 digits, 11 segments
10: 6 digits, 10 segments
11: 7 digits, 9 segments
PT6955 V1.5
-5-
June, 2005