C8051F336/7/8/9
7.3.2. Window Detector In Differential Mode
Figure 7.6 shows two example window comparisons for right-justified, differential data, with
ADC0LTH:ADC0LTL = 0x0040 (+64d) and ADC0GTH:ADC0GTH = 0xFFFF (–1d). In differential mode, the
measurable voltage between the input pins is between –VREF and VREF x (511/512). Output codes are
represented as 10-bit 2s complement signed integers. In the left example, an AD0WINT interrupt will be
generated if the ADC0 conversion word (ADC0H:ADC0L) is within the range defined by
ADC0GTH:ADC0GTL and ADC0LTH:ADC0LTL (if 0xFFFF (–1d) < ADC0H:ADC0L < 0x0040 (64d)). In the
right example, an AD0WINT interrupt will be generated if the ADC0 conversion word is outside of the range
defined by the ADC0GT and ADC0LT registers (if ADC0H:ADC0L < 0xFFFF (–1d) or
ADC0H:ADC0L > 0x0040 (+64d)). Figure 7.7 shows an example using left-justified data with the same
comparison values.
ADC0H:ADC0L
0x01FF
ADC0H:ADC0L
0x01FF
Input Voltage
(Px.x - Px.x)
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
VREF x (511/512)
AD0WINT
not affected
AD0WINT=1
0x0041
0x0041
VREF x (64/512)
VREF x (-1/512)
0x0040
0x003F
ADC0LTH:ADC0LTL
VREF x (64/512)
VREF x (-1/512)
0x0040
0x003F
ADC0GTH:ADC0GTL
AD0WINT
not affected
AD0WINT=1
0x0000
0xFFFF
0x0000
0xFFFF
ADC0GTH:ADC0GTL
ADC0LTH:ADC0LTL
0xFFFE
0xFFFE
AD0WINT=1
AD0WINT
not affected
0x0200
0x0200
-VREF
-VREF
Figure 7.6. ADC Window Compare Example: Right-Justified Differential Data
ADC0H:ADC0L
0x7FC0
ADC0H:ADC0L
0x7FC0
Input Voltage
(Px.x - Px.x)
Input Voltage
(Px.x - Px.y)
VREF x (511/512)
VREF x (511/512)
AD0WINT
not affected
AD0WINT=1
0x1040
0x1040
VREF x (64/512)
VREF x (-1/512)
0x1000
0x0FC0
ADC0LTH:ADC0LTL
VREF x (64/512)
VREF x (-1/512)
0x1000
0x0FC0
ADC0GTH:ADC0GTL
AD0WINT
not affected
AD0WINT=1
0x0000
0xFFC0
0x0000
0xFFC0
ADC0GTH:ADC0GTL
ADC0LTH:ADC0LTL
0xFF80
0xFF80
AD0WINT=1
AD0WINT
not affected
0x8000
0x8000
-VREF
-VREF
Figure 7.7. ADC Window Compare Example: Left-Justified Differential Data
54
Rev. 0.2
SILICON [ SILICON ]
