Maxim Integrated DS4830A Optical Microcontroller - Manual (Page 75)

DS4830A User’s Guide
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times in the QT list). The quick trip list can be filled sequentially with data 05h (channel 5 + single-ended), 06h
(channel 6 + single-ended), 17h (channel 7 + differential mode) and 06h (channel 6 + single-ended). See Table 9-2
for the quick trip list configurations.
To scan these list registers shown in Table 9-2, the QTSTART bits are set to 0 (0000b) and the QTSTOP bits are
set to 3 (0011b). Each channel is compared twice (see Figure 9-2). First the low trip threshold (LT) is compared and
then the high trip threshold (HT). The sequence of comparisions is shown is Figure 9-2.
Table 9-2: Quick Trip List Configuration
Quick Trip Start address (QTSTART) = 0
Quick Trip Stop address (QTEND) = 3
Channel 5
LT HT
Channel 6
LT HT
Channel 7
LT HT
……….
Channel 5
LT HT
Channel 6
LT HT
Channel 7
LT HT
……….
Channel 6*
LT HT
Channel 6*
LT HT
* Note: Channels can be defined multiple times in the list.
Figure 9-2: Quick Trip Operation
9.1.3 – Setting Quick Trip Thresholds
The quick trip threshold can be calculated by using the following formula.
Table 9-3 demonstrates Quick Trip low and high threshold configuration.
Table 9-3: Quick Trip Low Threshold Configuration
QTCN = 0x0000; //Low Threshold Configuration Register, Index = 0
QTDATA = 0x00FE; //0.6V Low Threshold Configuration for List0 Configuration
QTDATA = 0x0153; //0.8V Low Threshold Configuration for List1 Configuration
QTDATA = 0x01A7; //1.0V Low Threshold Configuration for List2 Configuration
QTDATA = 0x01D1; //1.1V Low Threshold Configuration for List3 Configuration
QT LIST
NUMBER
QTDATA DESCRIPTION
LIST REGISTERS USED FOR
COMPARISON
0 05h Channel 5 (S5) in single-ended mode LT0 and HT0
1 06h Channel 6 (S6) in single-ended mode LT1 and HT1
2 17h Channel 7(S14-S15) in differential mode LT2 and HT2
3 06h Channel 6 (S6) in single-ended mode LT3 and HT3
QT LIST NUMBER LOW THRESHOLD VALUE (AS EXAMPLE) QTDATA
0 0.6V 0x00FE
1 0.8V 0x0153
2 1.0V 0x01A7
3 1.1V 0x01D1