LX1977IDU MICROSEMI [Microsemi Corporation], LX1977IDU Datasheet - Page 17

• Manufacturer Part Number: LX1977IDU
• Description: SMBus Ambient Light Sensor
• Manufacturer: MICROSEMI [Microsemi Corporation]

ALS ADC Data Register 06h, 07h (R)
Copyright © 2010
Rev. 1.0, 2010-03-25
Index Address = 00000100b, 00000101b or 04h, 05h
Access = Read / Write
Default = 11111111b, 00001111b
value for the period of time set per INT_PERSIST_CTRL (register 01h bit 2, 1, 0), The INT_FLAG will be set to 1 and if the
INT_ENA is 1, the INT pin will be pulled low to indicate an interrupt on the INT pin.
than this register value for consecutive five times, i.e. 5 x 100 = 500ms, then an interrupt flag INT_FLAG will be set and if
INT_ENA = 1, the INT pin will be asserted low. If the INT_PERSIST_CTRL programmed time period is not reached and a
new D
will be reset to zero. If the INT_PERSIST_CTRL programmed time period is not reached and a new D
than Low Threshold value, the counter starts over at ‘1’.
Index Address = 00000110b, 00000111b or 06h, 07h
Access = Read Only
Default = 00000000h, 00000000h
will start another conversion again. Note that registers 06h and 07h act as a buffer between the ADC output counter and the
SMBus interface. Therefore, even when an ADC conversion is in process, the last conversion result will still be available in the
registers to read.
greater than 25ms (in 10.24kHz Mode), Read Word Protocol should be used to read the two bytes of ADC data. If data is read
by using Read Byte Protocol two consecutive times to read register 06h and 07h sequentially, the data in these registers might
be updated before the time of executing the second Read Byte Protocol. Thus, the second read byte may not correspond to the
original value
out the lower byte to reduce the communication time. Since for these integration times, the ADC results will be always less or
equal to 255 and only data in register 06h will be relevant. The ADC result is updated per the integration time set by T
(register 01h, bit 4, 3) when ADC is enabled by START_ADC (register 00h, bit 5).
process, the read data will correspond to the last conversion result.
Data bit 7
These two registers set the high threshold value of the interrupt function. If the ALS readout D
For example, if INT_PERSIST_CTRL = 101 and the integration time is set to 100ms, and if the D
Bit 7 to bit 4 in register 05h are always zero and can not be changed.
After each ADC conversion, the ADC output data will be stored in registers 06h and 07h. Once the data is stored, the ADC
Note that for the purpose of ADC data integrity control, when T
When T
These two registers can be read any time even while the ADC conversion is in process. When an ADC conversion is in
TM
COUNT
7
7
0
INT
value is between the Low Threshold value and this High Threshold value, the counter for INT_PERSIST_CTRL
is set to 6.25ms (in 40.96kHz Mode) or 25ms (in 10.24 kHz Mode), Read Byte Protocol could be used to read
Data bit 6
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0
6
6
Table 33: ALS ADC D
Table 32: ALS ADC D
Data bit 5
5
5
0
Analog Mixed Signal Group
Data bit 4
®
Microsemi
0
4
4
COUNT
COUNT
Higher Byte Register 07h
Lower Byte Register 06h
Data bit 11
Data bit 3
3
3
SMBus Ambient Light Sensor
INT
is greater than 6.25ms (in 40.96kHz Mode), or T
P
Data bit 10
RODUCTION
Data bit 2
2
2
D
Data bit 1
Data bit 9
ATASHEET
1
1
COUNT
COUNT
COUNT
Data bit 0
Data bit 8
is higher than this
LX1977
value is higher
0
0
value is lower
INT
Page 17
_SET
INT
is