TSL2568 Datasheet, PDF (20/36 Pages) TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS – LIGHT-TO-DIGITAL CONVERTER

TSL2568, TSL2569
LIGHT-TO-DIGITAL CONVERTER
TAOS091D − DECEMBER 2008
APPLICATION INFORMATION: SOFTWARE
The following example pseudo code illustrates the configuration of an SMB Alert style interrupt when the light
intensity changes 20% from the current value, and persists for 3 conversion cycles:
// Read current light level
Address = 0x39
//Slave addr also 0x29 or 0x49
Command = 0xAC
//Set Command bit and Word bit
ReadWord (Address, Command, DataLow, DataHigh)
Channel0 = (256 * DataHigh) + DataLow
//Calculate upper and lower thresholds
T_Upper = Channel0 + (0.2 * Channel0)
T_Lower = Channel0 – (0.2 * Channel0)
//Write the lower threshold register
Command = 0xA2
//Addr lower threshold reg, set Word Bit
WriteWord (Address, Command, T_Lower.LoByte, T_Lower.HiByte)
//Write the upper threshold register
Command = 0xA4
//Addr upper threshold reg, set Word bit
WriteWord (Address, Command, T_Upper.LoByte, T_Upper.HiByte)
//Enable interrupt
Command = 0x86
Data = 0x23
WriteByte(Address, Command, Data)
//Address interrupt register
//SMBAlert style, PERSIST = 3
In order to generate an interrupt on demand during system test or debug, a test mode (INTR = 11) can be used.
The following example illustrates how to generate an interrupt on demand:
// Generate an interrupt
Address = 0x39
Command = 0x86
Data = 0x30
WriteByte(Address, Command, Data)
//Slave addr also 0x29 or 0x49
//Address Interrupt register
//Test interrupt
//Interrupt line should now be low
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