Document # 001-20559 Rev. *D
245
21.
Analog Reference
This chapter discusses the Analog Reference generator and its associated register. The reference generator establishes a
set of three internally fixed reference voltages for AGND, RefHi, and RefLo. For a quick reference of all PSoC registers in
address order, refer to the
Register Details chapter on page 47
21.1
Architectural Description
The PSoC device is a single supply part, with no negative
voltage available or applicable.
shows the ana-
log reference control schematic.
Analog ground (AGND) is constructed near mid-supply. This
ground is routed to all analog blocks and separately buffered
within each block. Note that there may be a small offset volt-
age between buffered analog grounds. RefHi and RefLo sig-
nals are generated, buffered, and routed to the analog
blocks. RefHi and RefLo are used to set the conversion
range (that is, span) of
) converters. RefHi and RefLo can also be
used to set thresholds in comparators the two column PSoC
devices.
The reference array supplies voltage to all blocks and cur-
rent to the Switched Capacitor blocks. At higher block clock
rates, there is increased reference current demand; the ref-
erence power should be set equal to the highest power level
of the analog blocks used.
Figure 21-1. Analog Reference Structure
Figure 21-2. Analog Reference Control Schematic
V ss
V A G N D
A G N D
R efH
R efL
V
R efH i
V
R efLo
Vbandgap
Vdd/2
P2[6]
Vdd
Vss
RefHi to
Analog
Blocks
RefLo to
Analog
Blocks
AGND
P2[4] (External Cap)
Vbandgap
P2[4]
x1
x1
x1.6
x2
2 Analog Columns
8.1K
8.1K
Summary of Contents for PSoC CY8C23533
Page 4: ...Contents Overview 4 Document 001 20559 Rev D Section G Glossary 385 Index 401 ...
Page 16: ...Contents Overview 16 Document 001 20559 Rev D ...
Page 24: ...24 Document 001 20559 Rev D Section A Overview ...
Page 30: ...30 Document 001 20559 Rev D Pin Information ...
Page 54: ...54 Document 001 20559 Rev D Supervisory ROM SROM ...
Page 60: ...60 Document 001 20559 Rev D RAM Paging ...
Page 68: ...68 Document 001 20559 Rev D Interrupt Controller ...
Page 76: ...12 Document 001 20559 Rev D General Purpose IO GPIO ...
Page 82: ...18 Document 001 20559 Rev D Internal Main Oscillator IMO ...
Page 84: ...20 Document 001 20559 Rev D Internal Low Speed Oscillator ILO ...
Page 90: ...26 Document 001 20559 Rev D External Crystal Oscillator ECO ...
Page 94: ...30 Document 001 20559 Rev D Phase Locked Loop PLL ...
Page 106: ...42 Document 001 20559 Rev D Sleep and Watchdog ...
Page 228: ...164 Document 001 20559 Rev D Section D Digital System ...
Page 234: ...170 Document 001 20559 Rev D Array Digital Interconnect ADI ...
Page 278: ...214 Document 001 20559 Rev D Digital Blocks ...
Page 296: ...232 Document 001 20559 Rev D Analog Interface ...
Page 304: ...240 Document 001 20559 Rev D Analog Array ...
Page 308: ...244 Document 001 20559 Rev D Analog Input Configuration ...
Page 312: ...248 Document 001 20559 Rev D Analog Reference ...
Page 338: ...274 Document 001 20559 Rev D Section F System Resources ...
Page 354: ...290 Document 001 20559 Rev D Multiply Accumulate MAC ...
Page 374: ...310 Document 001 20559 Rev D I2C ...
Page 400: ...336 Document 001 20559 Rev D Section G Glossary ...