Silicon Laboratories C8051F347 - Manual (Page 55)

Rev. 1.3 55
C8051F340/1/2/3/4/5/6/7/8/9/A/B/C/D
5.4.2. Window Detector In Differential Mode
Figure 5.8 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*(511/512). Output codes are rep-
resented as 10-bit 2’s complement signed integers. In the left example, an AD0WINT interrupt will be gen-
erated 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 5.9 shows an example using left-justified data with equivalent ADC0GT and ADC0LT register set-
tings.
Figure 5.8. ADC Window Compare Example: Right-Justified Differential Data
Figure 5.9. ADC Window Compare Example: Left-Justified Differential Data
0x01FF
0x0041
0x0040
0x003F
0x0000
0xFFFF
0xFFFE
0x0200 -VREF
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
VREF x (64/512)
VREF x (-1/512)
0x01FF
0x0041
0x0040
0x003F
0x0000
0xFFFF
0xFFFE
0x0200 -VREF
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
VREF x (64/512)
VREF x (-1/512)
AD0WINT=1
AD0WINT
not affected
AD0WINT
not affected
ADC0LTH:ADC0LTL
ADC0GTH:ADC0GTL
AD0WINT
not affected
AD0WINT=1
AD0WINT=1
ADC0H:ADC0L ADC0H:ADC0L
ADC0GTH:ADC0GTL
ADC0LTH:ADC0LTL
0x7FC0
0x1040
0x1000
0x0FC0
0x0000
0xFFC0
0xFF80
0x8000 -VREF
Input Voltage
(Px.x - Px.y)
VREF x (511/512)
VREF x (64/512)
VREF x (-1/512)
0x7FC0
0x1040
0x1000
0x0FC0
0x0000
0xFFC0
0xFF80
0x8000 -VREF
Input Voltage
(Px.x - Px.x)
VREF x (511/512)
VREF x (64/512)
VREF x (-1/512)
AD0WINT=1
AD0WINT
not affected
AD0WINT
not affected
ADC0LTH:ADC0LTL
ADC0GTH:ADC0GTL
AD0WINT
not affected
ADC0GTH:ADC0GTL
AD0WINT=1
AD0WINT=1
ADC0H:ADC0L ADC0H:ADC0L
ADC0LTH:ADC0LTL