Datasheet

21
Atmel MSL2010 [DATASHEET]
42072A–AVR–05/2013
14.4 Efficiency Optimizer Control Register (EOCTRL, 0x40)
DThresh sets the voltage feedback threshold for D, The LED string MOSFET drain connection.
D Threshold = (<DThresh>  150mV) + 250mV. This is how the device monitors V
LED
to control the magnitude of the EO
current. The default value for DThresh is 1V.
Table 14-4. Efficiency Optimizer Control Register (FBOCTRL, 0x40), default highlighted
These registers control access to the EEPROM. See “EEPROM and Power-Up Defaults” on page 18 and “EEPROM
Address and Control/Status Registers” on page 18
for information.
15. I²C Serial Interface
The MSL2010 operates as a slave that sends and receives data through an I²C/SMBus compatible 2-wire serial
interface. The interface is not needed for operation, but is provided to allow control and monitoring of device functions.
These functions include changing the string current reference feedback voltages, reading and adjusting the fault
response behavior and status, and programming the EEPROM. The I²C/SMBus compatible interface is suitable for
100kHz, 400kHz and 1MHz communication. The interface uses data I/O SDA and clock input SCL to achieve
bidirectional communication between master and slaves.
The master, typically a microcontroller, initiates all data transfers, and generates the clock that synchronizes the
transfers. SDA operates as both an input and an open-drain output. SCL operates only as an input, and does not perform
clock-stretching. Pull-up resistors are required on SDA, and SCL.
Figure 15-1. I
2
C Interface Connections
A transmission consists of a START condition sent by a master, a 7-bit slave address plus one R/W bit, an acknowledge
bit, none or many data bytes each separated by an acknowledge bit, and a STOP condition (Figure 15-2, Figure 15-4 and
Figure 15-5 on page 23).
Register
Address/
Default
Register data
D7 D6 D5 D4 D3 D2 D1 D0
FBOCTRL 0x40 Reserved[4:0] DThresh[3:0]
Defaults 0xE5
1 1 1 0 0 1 0 1
D Threshold = (0  150mV) + 250mV = 0.25V
1 1 1 0 0 0 0 0
D Threshold = (5  150mV) + 250mV = 1V
1 1 1 0 0 1 0 1
D Threshold = (15  150mV) + 250mV = 2.5V
1 1 1 0 1 1 1 1
MASTER
(μC)
SDA
SCL
SDA
SCL
MSL2010
V
I2C
2 x 2.2k
TYPICAL