lm2756tmx National Semiconductor Corporation, lm2756tmx Datasheet - Page 10

• Manufacturer Part Number: lm2756tmx
• Description: Multi-display Inductorless Led Driver With 32 Exponential Dimming Steps In ?smd
• Manufacturer: National Semiconductor Corporation

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master releases the SDIO line (HIGH) during the acknowl-
edge clock pulse. The LM2756 pulls down the SDIO line
during the 9th clock pulse, signifying an acknowledge. The
LM2756 generates an acknowledge after each byte is re-
ceived.
After the START condition, the I
dress. This address is seven bits long followed by an eighth
I
The chip address for LM2756 is 0110110, or 36h.
INTERNAL REGISTERS OF LM2756
2
Register
General Purpose
Register
Group A
Brightness Control
Register
Group B
Brightness Control
Register
Group C
Brightness Control
Register
Ramp Step Time
Register
VF Monitor Delay
Ragister
C COMPATIBLE CHIP ADDRESS
FIGURE 4. Chip Address
Internal Hex
Address
10h
A0h
B0h
C0h
20h
60h
ack = acknowledge (SDIO pulled down by either master or slave)
2
C master sends a chip ad-
Power On Value
0000 0000
1110 0000
1111 1000
1111 1000
1111 0000
1111 1100
id = chip address, 36h for LM2756
FIGURE 3. Write Cycle
w = write (SDIO = "0")
30009709
r = read (SDIO = "1")
10
bit which is a data direction bit (R/W). The LM2756 address
is 36h. For the eighth bit, a “0” indicates a WRITE and a “1”
indicates a READ. The second byte selects the register to
which the data will be written. The third byte contains data to
write to the selected register.
Note: ENA: Enables DxA LED drivers (Main Display)
FIGURE 6. Brightness Control Register Description
FIGURE 5. General Purpose Register Description
ENB: Enables DxB LED drivers (Aux Lighting)
ENC: Enables D1C LED driver (Indicator Lighting)
SD53: Shuts down driver D53
SD62: Shuts down driver D62
53A: Configures D53 to GroupA
62A: Configures D62 to GroupA
Internal Hex Address: 10h
30009712
30009708
30009705
30009706
30009707