Rainbow Electronics MAX8709 - Manual (Page 18)

MAX8709
High-Efficiency CCFL Backlight
Controller with SMBus Interface
18 ______________________________________________________________________________________
Brightness Register [BRIGHT4 – BRIGHT0]
(POR = 0b10111)
The 5-bit brightness register corresponds to the 5-bit
brightness code used in dimming control (See the
Dimming Control section). BRIGHT4 - BRIGHT0 =
0b11111 sets minimum brightness and BRIGHT4 -
BRIGHT0 = 0b00000 sets maximum brightness. Note that
the brightness-register polarity of command bytes 0xA9
and 0xAA are inverted from that of command byte 0x01.
Shutdown-Mode Register [SHMD2–SHMD0]
(POR = 0b001)
The 3-bit shutdown-mode register configures the oper-
ation of the device when the SUS pin is toggled as
described in Table 4. The shutdown-mode register can
also be used to directly shut off the CCFL regardless of
the state of SUS (Table 5).
Table 3. Commands Description
DATA REGISTER BIT ASSIGNMENT
SMBus
PROTOCOL
COMMAND
BYTE*
POR
STATE
BIT 7
(MSB)
BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1
BIT 0
(LSB)
Read and
Write
0x01
0b0XXX XX01
0x17 0 0 0
BRIGHT4
(MSB)
BRIGHT3 BRIGHT2 BRIGHT1
BRIGHT0
(LSB)
Read and
Write
0x02
0b0XXX XX10
0xF9 STATUS1 STATUS0 1 1 1 SHMD2 SHMD1 SHMD0
Read Only
0x03
0b0XXX XX11
0x0C
ChipID7
0
ChipID6
0
ChipID5
0
ChipID4
0
ChipID3
1
ChipID2
1
ChipID1
0
ChipID0
1
Read Only
0x04
0b0XXX XX00
0x00
ChipRev7
0
ChipRev6
0
ChipRev5
0
ChipRev4
0
ChipRev3
0
ChipRev2
0
ChipRev1
0
ChipRev0
0
Read and
Write
0xAA
0b10XX XXX0
0x40
BRIGHT4
(MSB)
BRIGHT3 BRIGHT2 BRIGHT1
BRIGHT0
(LSB)
1 STATUS1 STATUS0
Read and
Write
0XA9
0b10XX XXX1
0x40
BRIGHT4
(MSB)
BRIGHT3 BRIGHT2 BRIGHT1
BRIGHT0
(LSB)
0 STATUS1 STATUS0
Read Only
0xFE
0b11XX XXX0
0x4D
MfgID7
0
MfgID6
1
MfgID5
0
MfgID4
0
MfgID3
1
MfgID2
1
MfgID1
0
MfgID0
1
Read Only
0xFF
0b11XX XXX1
0x0C
ChipID7
0
ChipID6
0
ChipID5
0
ChipID4
0
ChipID3
1
ChipID2
1
ChipID1
0
ChipID0
1
*The hexadecimal command byte shown is recommended for maximum forward compatibility with future products.
X = Don’t care.
Table 4. SHMD Register Bit Descriptions
BIT NAME
POR
STATE
DESCRIPTION
2 SHMD2 0
SHMD2 = 1 forces the lamp off and sets STATUS1. SHMD2 = 0 allows the lamp to operate,
although it may still be shut down by SUS (depending on the state of SHMD1 and SHMD0).
1 SHMD1 0
When SUS = 0, this bit has no effect. SUS = 1 and SHMD1 = 1 forces the lamp off and sets STATUS1.
SUS = 1 and SHMD1 = 0 allows the lamp to operate, although it may still be shut down by the SHMD2 bit.
0 SHMD0 1
When SUS = 1, this bit has no effect. SUS = 0 and SHMD0 = 1 forces the lamp off and sets STATUS1.
SUS = 0 and SHMD0 = 0 allows the lamp to operate, although it may still be shut down by the SHMD2 bit.