Datasheet

18
Atmel MSL2010 [DATASHEET]
42072A–AVR–05/2013
13. Control Registers
Table 13-1. MSL2010 Register Map (Do not change unspecified registers or bits).
13.1 EEPROM and Power-Up Defaults
An on-chip EEPROM holds all the default register values (Table 13-1 on page 18). At power-up the data in the EEPROM
automatically copy directly to control registers 0x00 thru 0x51, setting up the device for operation.
Any changes made to registers 0x00 thru 0x51 after power-up are not reflected in the EEPROM and are lost when power
is removed from the device, or when the enable input EN is forced low. If a different power-up condition is desired
program the values into the EEPROM via the serial interface as explained in the next section, or contact the factory to
inquire about ordering a customized power-up setting.
13.2 EEPROM Address and Control/Status Registers
The EEPROM can be visualized as an image of the control registers from 0x00 thru 0x69. Change an EEPROM register
value by writing the new value into the associated control register, and then instructing the device to program that value
into the EEPROM. Two control registers facilitate this process, the EEPROM address register E2ADDR (0x60), and the
EEPROM control register E2CTRL (0x61). Into E2ADDR write the location of the data that is to be programmed into the
EEPROM, and write 0x03 to E2CTRL to command the device to program that data into the EEPROM. Programming the
EEPROM takes a finite amount of time; after sending a command to E2CTRL wait 5ms, then end the write cycle by
writing 0x00 to E2CTRL.
Example: Change the string current feedback voltage MREF to 100mV.
Commands: To register 0x20 (MREF) write 0x32 (the new value for MREF). To register 0x60 (E2ADDR) write 0x20 (the
address of the MREF register). To register 0x61 (E2CTRL) write 0x03 (the command to copy the value to EEPROM).
Wait 5ms. To register 0x61 (E2CTRL) write 0x00, to turn off EEPROM access.
Result: The value 0x32, located in the MREF register, is programmed into the EEPROM and becomes the new power-
up default value for MREF.
Summary:
0x20 32
0x60 20
0x61 03
Address and
Register name
Function
Default
value
Bit functions
D7 D6 D5 D4 D3 D2 D1 D0
Control and Monitor Registers
0x00 through 0x1F RAM 0xXX Free RAM
0x20 SREF
LED String
MOSFET Source
Feedback
Reference Voltage
0x64 S
REF
= 2mV per LSB
0x21 CSREF
Boost Current
Sense Reference
Feedback Voltage
0x64 CS
REF
= 2mV per LSB
0x40 EOCTRL
Efficiency
Optimizer
0xE5 Reserved[4:0] DThresh[3:0]
0x60 E2ADDR EEPROM Address 0x00 – EEPROM Address Pointer
0x61 E2CTRL EEPROM Control 0x00 – – – – – RWCTRL[2:0]
Unused and Reserved Registers