XE8000EV101 Semtech, XE8000EV101 Datasheet - Page 89

• Manufacturer Part Number: XE8000EV101
• Description: EVAL BOARD FOR XE8801AMI027LF
• Manufacturer: Semtech
• Type: MCUr

Specifications of XE8000EV101

• Contents: Fully Assembled Evaluation Board
• For Use With/related Products: XE88LC01AMI027
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

16.4 ZoomingADC™ Description
Figure 16-2 gives a more detailed description of the acquisition chain.
16.4.1
Figure 16-1 shows the general block diagram of the acquisition chain (AC). A control block (not shown in Figure
16-1) manages all communications with the CoolRisc™ microcontroller.
channels.
The core of the zooming section is made of three differential programmable amplifiers (PGA). After selection of a
combination of input and reference signals V
1 to 3. Fine gain programming up to 1'000V/V is possible. In addition, the last two stages provide programmable
offset. Each amplifier can be bypassed if needed.
The output of the PGA stages is directly fed to the analog-to-digital converter (ADC), which converts the signal
V
© Semtech 2005
Analog inputs can be selected among eight input channels, while reference input is selected between two differential
IN,ADC
into digital.
pos.
pos.
pos.
pos.
6:0
6:0
5:1
7:6
5:4
3:0
7
7
7
6
0
Acquisition Chain
RegAcCfg3
RegAcCfg4
RegAcCfg5
RegAcCfg2
PGA3_OFFSET[6:0]
PGA2_OFFSET[3:0]
PGA3_GAIN[6:0]
PGA2_GAIN[1:0]
PGA1_GAIN
AMUX[4:0]
reserved
FIN[1:0]
VMUX
BUSY
DEF
rw
r w
r w
rw
r
r w
rw
r
w r0
r w
r w
rw
r w
r w
r w
reset
0 resetsystem
0000000
resetsystem
reset
0
0000000
resetsystem
reset
0 resetsystem
0
00000
resetsystem
0 resetsystem
00 resetsystem
00 resetsystem
reset
0000
resetsystem
IN
and V
Table 16-6: RegAcCfg2
Table 16-7: RegAcCfg3
Table 16-8: RegAcCfg4
Table 16-9: RegAcCfg5
REF
, the input voltage is modulated and amplified through stages
16-4
description
description
description
description
Input channel configuration selector
Sampling frequency selection
Selects default configuration
PGA2 stage offset selection
PGA3 stage offset selection
Reference channel selector
PGA2 stage gain selection
PGA1 stage gain selection
PGA3 stage gain selection
Activity flag
Unused
XE8801A – SX8801R
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