BUF12840_12 Datasheet, PDF (8/26 Pages) Texas Instruments – Programmable Gamma-Voltage Generator with Integrated Two-Bank Memory and External EEPROM

BUF12840
SBOS519A – OCTOBER 2010 – REVISED JULY 2011
V_SD
0.1mF
V_S
1mF
10kW
10kW
0.1mF
0.1mF
TCON
EEPROM A0
A1
BUF12840
V_SD
OUT0
OUT1
OUT2
V_S
OUT3
OUT4
OUT5
OUT6
OUT7
EA1
OUT8
EA0
OUT9
EN
OUT10
LD
OUT11
SDA
SCL
BKSEL
A0
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Figure 10. Typical Application Configuration
DATA RATES
The two-wire bus operates in one of three speed
modes:
• Standard: allows a clock frequency of up to
100kHz;
• Fast: allows a clock frequency of up to 400kHz;
and
• High-speed mode (also called Hs mode): allows a
clock frequency of up to 3.4MHz.
The BUF12840 is fully compatible with all three
modes. No special action is required to use the
device in Standard or Fast modes, but High-speed
mode must be activated. To activate High-speed
mode, send a special address byte of 00001 xxx, with
SCL ≤ 400kHz, following the START condition; where
xxx are bits unique to the Hs-capable master, which
can be any value. This byte is called the Hs master
code. Table 2 provides a reference for the
High-speed mode command code. (Note that this
configuration is different from normal address
bytes—the low bit does not indicate read/write
status.) The BUF12840 responds to the High-speed
command regardless of the value of these last three
bits. The BUF12840 does not acknowledge this byte;
the
communication
protocol
prohibits
acknowledgment of the Hs master code. Upon
receiving a master code, the BUF12840 switches on
its Hs mode filters, and communicates at up to
3.4MHz. Additional high-speed transfers may be
transmitted without resending the Hs mode byte by
generating a repeat START without a STOP. The
BUF12840 switches out of Hs mode with the next
STOP condition.
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