Analog Devices ADuC7026 Application notes

Analog Devices
Brand
Analog Devices
Model
ADuC7026
Type
Application notes

Analog Devices ADuC7026 is a low-power, 16-bit microcontroller with an 8-channel, 12-bit ADC, a voltage reference, and a comparator. It is ideal for applications that require high precision and low power consumption, such as portable medical devices, industrial controls, and data acquisition systems.

The ADuC7026 has a number of features that make it well-suited for these applications, including:

  • A high-performance 16-bit CPU with a clock speed of up to 40 MHz
  • An 8-channel, 12-bit ADC with a conversion time of 10 μs
  • A 2.5 V voltage reference with a temperature drift of 10 ppm/°C
  • A comparator with a threshold voltage that can be set to any value between 0 and 2.5 V

Analog Devices ADuC7026 is a low-power, 16-bit microcontroller with an 8-channel, 12-bit ADC, a voltage reference, and a comparator. It is ideal for applications that require high precision and low power consumption, such as portable medical devices, industrial controls, and data acquisition systems.

The ADuC7026 has a number of features that make it well-suited for these applications, including:

  • A high-performance 16-bit CPU with a clock speed of up to 40 MHz
  • An 8-channel, 12-bit ADC with a conversion time of 10 μs
  • A 2.5 V voltage reference with a temperature drift of 10 ppm/°C
  • A comparator with a threshold voltage that can be set to any value between 0 and 2.5 V
AN-744
APPLICATION NOTE
One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com
ADuC7026 Evaluation Board Reference Guide
MicroConverter® ADuC7026
Development System
by Aude Richard
Rev. A | Page 1 of 16
AN-744
Rev. A | Page 2 of 16
TABLE OF CONTENTS
Evaluation Board Overview ............................................................ 3
Considerations.............................................................................. 3
Evaluation Board Features............................................................... 4
Power Supply................................................................................. 4
RS-232 Interface ........................................................................... 4
Emulation Interface...................................................................... 4
Crystal Circuit............................................................................... 4
External Reference (ADR291) .................................................... 4
Reset/Download/IRQ0 Push Buttons........................................ 4
Power Indicator/General-Purpose LEDs .................................. 5
Analog I/O Connections ............................................................. 5
General-Purpose Prototype Area............................................... 5
External Memories and Latch Footprint................................... 5
DIP Switch Link Options................................................................. 6
S1-1 V
REF
........................................................................................ 6
S1-2 V
OCM
....................................................................................... 6
S1-3 POT ....................................................................................... 6 T
S1-4 ADC3 .....................................................................................6
S1-5 VIN− ......................................................................................6
S1-6 VIN+ ......................................................................................6
S1-7 ADC4 .....................................................................................6
S1-8 LED.........................................................................................6
External Connectors .........................................................................7
Analog I/O Connector J3.............................................................7
Power Supply Connector J5 .........................................................7
Emulation Connector J4...............................................................7
Serial Interface Connector J1.......................................................7
Digital I/O Connector J2..............................................................7
External Memory Interface ..............................................................9
Connections...................................................................................9
Potentiometer Demonstration Circuit ........................................ 10
Schematic......................................................................................... 11
ADuC7026 Evaluation Board Parts List...................................... 13
AN-744
Rev. A | Page 3 of 16
EVALUATION BOARD OVERVIEW
The ADuC7026 evaluation board has the following features:
• 2-layer PCB (4” × 5” form factor).
• 9 V power supply regulated to 3.3 V on board.
• 4-pin UART header to connect to RS-232 interface cable.
• 20-pin standard JTAG connector.
• Demonstration circuit.
• 32.768 kHz watch crystal to drive the PLL clock.
• ADR291 2.5 V external reference chip.
• Reset/download/IRQ0 push buttons.
• Power indicator/general-purpose LEDs.
• Access to all ADC inputs and DAC output from external
header. All device ports are brought out to external
header pins.
• Surface-mount and through-hole general-purpose
prototype area.
• External memories and latch footprint.
CONSIDERATIONS
• This document refers to the MicroConverter ADuC7026
evaluation board Revision B1.
• All references in this document to the physical orientation
of components on the board are made with respect to a
component-side view of the board with the prototype area
appearing in the bottom of the board.
• The board is laid out to minimize coupling between the
analog and digital sections of the board. To this end, the
ground plane is split with the analog section on the left
side and a digital plane on the right side of the board. The
regulated 3.3 V power supply is routed directly to the
digital section and is filtered before being routed into the
analog section of the board.
AN-744
Rev. A | Page 4 of 16
EVALUATION BOARD FEATURES
POWER SUPPLY
The user should connect the 9 V power supply via the 2.1 mm
input power socket (J5). The input connector is configured as a
center negative, that is, as GND on the center pin and +9 V on
the outer shield.
The 9 V supply is regulated via the Linear Voltage Regulator U5.
The 3.3 V regulator output is used to drive the digital side of the
board directly. The 3.3 V supply is also filtered and then used to
supply the analog side of the board.
When on, the LED (D3) indicates that a valid 3.3 V supply is
being driven from the regulator circuit. All active components
are decoupled with 0.1 μF at device supply pins to ground.
RS-232 INTERFACE
The ADuC7026 (U1) P1.1 and P1.0 lines are connected to the
RS-232 interface cable via Connector J1. The interface cable
generates the required level shifting to allow direct connection
to a PC serial port. Ensure that the cable supplied is connected
to the board correctly, that is, DVDD is connected to DVDD
and DGND is connected to DGND.
EMULATION INTERFACE
Nonintrusive emulation and download are possible on the
ADuC7026, via JTAG, by connecting a JTAG emulator to the
J4 connector.
CRYSTAL CIRCUIT
The board is fitted with a 32.768 kHz crystal, from which the
on-chip PLL circuit can generate a 41.78 MHz clock.
EXTERNAL REFERENCE (ADR291)
The external 2.5 V Reference Chip U2 has two functions. It is
provided on the evaluation board to demonstrate the external
reference option of the ADuC7026 but its main purpose is to
generate the V
OCM
voltage of the differential amplifier if
required.
RESET/DOWNLOAD/IRQ0 PUSH BUTTONS
A reset push button is provided to allow the user to reset the
part manually. When the button is pushed, the reset pin of the
ADuC7026 is pulled to DGND. Because the reset pin on the
ADuC7026 is Schmidt triggered internally, there is no need to
use an external Schmidt trigger on this pin.
When pushed, the IRQ0 push button switch drives P0.4/IRQ0
high. This can be used to initiate an external interrupt 0.
To enter serial download mode, the user must pull the P0.0/BM
pin low while reset is toggled. On the evaluation board, serial
download mode can easily be initiated by holding down the
serial download push button (S2) while inserting and releasing
the reset button (S3) as shown in
Figure 1.
S3
(RESET = 1)
S2
(BM = 1)
(A) S3 AND S2 RELEASED
S2
(BM = 0)
S3
(RESET = 1)
(B) PUSH S2
S3
(RESET = 1)
S2
(BM = 0)
(D) RELEASE S3
S2
(BM = 0)
S3
(RESET = 0)
(C) PUSH S3
S2
(BM = 1)
S3
(RESET = 1)
(E) RELEASE S2
05032-001
Figure 1. Entering Serial Download Mode on the Evaluation Board
AN-744
Rev. A | Page 5 of 16
POWER INDICATOR/GENERAL-PURPOSE LEDS
A power LED (D3) is used to indicate that a sufficient supply is
available on the board. A general-purpose LED (D2) is directly
connected to P4.2 of the ADuC7026. When P4.2 is cleared, the
LED is turned on, and when P4.2 is set, the LED is turned off.
ANALOG I/O CONNECTIONS
All analog I/O connections are brought out on Header J3.
ADC0 and ADC1 are buffered using an AD8606 to evaluate
single-ended and pseudo differential mode. A potentiometer
can be connected to ADC0 (buffered).
ADC3 and ADC4 can be buffered with a single-ended to
differential op amp on-board, with the AD8132 used to evaluate
the ADC in fully differential mode.
ADC2 and ADC5 to ADC11 are not buffered. Be sure to follow
the data sheet recommendations when connecting signals to
these inputs.
DAC1 can be used to control the brightness of the LED D1,
when connected via the S1 switch.
GENERAL-PURPOSE PROTOTYPE AREA
General-purpose prototype areas are provided at the bottom of
the evaluation board for adding external components as
required in the user’s application. AV
DD
, AGND, V
DDIO
, and
DGND tracks are provided in the prototype area.
EXTERNAL MEMORIES AND LATCH FOOTPRINT
Footprints for a 32 k × 16 static RAM (CY7C1020CV33), a
64 k × 16 flash (AT29LV1024), and a16-bit latch are also
on-board. See the
External Memory Interface section.
AN-744
Rev. A | Page 6 of 16
DIP SWITCH LINK OPTIONS
S1-1 V
REF
Function
Connects the output of the 2.5 V external reference (ADR291)
to the V
REF
pin (Pin 68) of the ADuC7026.
Use
Slide S1-1 to the on position to connect the external reference
to the ADuC7026.
Slide S1-1 to the off position to use the internal 2.5 V reference
or a different external reference on the V
REF
pin of Header J3.
S1-2 V
OCM
Function
Connects 1.67 V to the V
OCM
pin of the AD8132. No extra
dc voltage is required on the board to use the ADC in
differential mode.
Use
Slide S1-2 to the on position to connect V
OCM
of the differential
amplifier to the 1.67 V divided output of the ADR291 reference.
Slide S1-2 to the off position to use a different voltage for V
OCM
by connecting a dc voltage to the V
OCM
pin of Header J3. Note
that the V
OCM
value is dependent on the reference value, as
shown in
Table 1.
Table 1. V
OCM
Range
V
REF
V
OCM
minimum V
OCM
maximum
2.5 V 1.25 V 2.05 V
2.048 V 1.024 V 2.276 V
1.25 V 0.75 V 2.55 V
S1-3 POT
Function
Connects the potentiometer output to ADC0. This input is
buffered by an AD8606. This is for demonstration purposes.
Use
Slide S1-3 to the on position to connect the potentiometer to
the op amp of the ADC0 input channel.
Slide S1-3 to the off position to use the ADC0 input on Header J3.
S1-4 ADC3
Function
Brings out ADC3 (Pin 80) on Header J3.
Use
Slide S1-4 to the on position to connect ADC3 of Header J3
directly to the ADC3 pin (Pin 80) of the ADuC7026.
Slide S1-4 to the off position to disconnect ADC3 of Header J3
from the ADC3 pin (Pin 80) of the ADuC7026.
S1-5 VIN−
Function
Connects the −OUT pin of the single-ended to differential op
amp (AD8132) to ADC3. S1-5 and S1-6 must be used together.
When VIN− is in the on position, VIN+ must also be in the on
position to use the differential op amp on Channel ADC3 and
Channel ADC4.
Use
Slide S1-5 to the on position to connect −OUT of the AD8132
to ADC3.
Slide S1-5 to the off position to use ADC3 without the AD8132.
S1-6 VIN+
Function
Connects the +OUT pin of the single-ended to differential op
amp (AD8132) to ADC4. When VIN+ is in the on position,
VIN− must also be in the on position to use the differential op
amp on Channel ADC3 and Channel ADC4.
Use
Slide S1-6 to the on position to connect +OUT of the AD8132
to ADC4.
Slide S1-6 to the off position to use ADC4 without the AD8132.
S1-7 ADC4
Use
Slide S1-7 to the on position to connect ADC4 of Header J3
directly to the ADC4 pin (Pin 1) of the ADuC7026.
Slide S1-7 to the off position to disconnect ADC4 of Header J3
from the ADC4 pin (Pin 1) of the ADuC7026.
S1-8 LED
Function
Connects the DAC1 output to the green LED of the
demonstration circuit, D1.
Use
Slide S1-8 to the on position to connect the DAC1 output to D1.
Slide S1-8 to the off position to use the DAC1 output on
Header J3.
AN-744
Rev. A | Page 7 of 16
EXTERNAL CONNECTORS
ANALOG I/O CONNECTOR J3
Connector J3 provides external connections for all ADC inputs,
reference inputs and DAC outputs. The pinout of the connector
is shown in
Table 2.
POWER SUPPLY CONNECTOR J5
Connector J5 allows for the connection between the evaluation
board and the 9 V power supply provided in the ADuC7026
development system.
EMULATION CONNECTOR J4
Connector J4 provides a connection of the evaluation board to
the PC via a USB cable and mIDAS link provided in the
ADuC7026 QuickStart™ Plus development system only.
SERIAL INTERFACE CONNECTOR J1
Connector J1 provides a simple connection of the evaluation
board to the PC via a PC serial port cable provided with the
ADuC7026 development system.
DIGITAL I/O CONNECTOR J2
Connector J2 provides external connections for all GPIOs. The
pinout of the connector is shown in
Table 3, with details of the
pin functions.
Table 2. Pin Functions for Analog I/O Connector J3
Pin No. Pin Description
J3-1 AV
DD
J3-2 AGND
J3-3 V
REF
J3-4 DAC
REF
J3-5 ADC0
J3-6 ADC1
J3-7 ADC2
J3-8 ADC3
J3-9 ADC4
J3-10 ADC5
J3-11 ADC6
J3-12 ADC7
J3-13 ADC8
J3-14 ADC9
J3-15 ADC10
J3-16 ADC11
J3-17 V
DIFF
J3-18 V
OCM
J3-19 DAC0
J3-20 DAC1
J3-21 DAC2
J3-22 DAC3
J3-23 ADC
NEG
J3-24 AGND
AN-744
Rev. A | Page 8 of 16
Table 3. Pin Functions for Digital I/O Connector J2
Pin No. Pin Description
J2-1 DGND
J2-2 P4.5
AD13/PLAO[13]
J2-3 P4.4
AD12/PLAO[12]
J2-4 P4.3
AD/11PLAO[11]
J2-5 P4.2
AD10/PLAO[10]
J2-6 P1.0
T1/SIN/SCL0/PLAI[0]
J2-7 P1.1
SOUT/SDA0/PLAI[1]
J2-8 P1.2
RTS/SCL1/PLAI[2]
J2-9 P1.3
CTS/SDA1/PLAI[3]
J2-10 P1.4
IRQ2/RI/CLK/PLAI[4]
J2-11 P1.5
IRQ3/DCD/MISO/PLAI[5]
J2-12 P4.1
AD9/PLAO[9]
J2-13 P4.0
AD8/PLAO[8]
J2-14 P1.6
DSR/MOSI/PLAI[6]
J2-15 P1.7
DTR/CSL/PLAO[0]
J2-16 P2.2
PWM0
L
/RS/PLAO[7]
J2-17 P2.1
PWM0
H
/WS/PLAO[6]
J2-18 P2.7
PWM1
L
/MS3
J2-19 P3.7
PWM
SYNC
/AD7/PLAI[15]
J2-20 P3.6
PWM
TRIP
/AD6/PLAI[14]
J2-21 P0.7
ECLK/XCLK/SIN/PLAO[4]
Pin No. Pin Description
J2-22 P2.0
CONV
START
/SOUT/PLAO[5]
J2-23 P0.5
IRQ1/ADC
BUSY
/MS0/PLAO[2]
J2-24 P0.4
IRQ0/PWM
TRIP
/MS1/PLAO[1]
J2-25 P3.5
PWM2
L
/AD5/PLAI[13]
J2-26 P3.4
PWM2
H
/AD4/PLAI[12]
J2-27 P2.6
PWM1
H
/MS2
J2-28 P2.5
PWM0
L
/MS1
J2-29 P0.3
TRST/A16/ADC
BUSY
J2-30 P2.4
PWM0
H
/MS0
J2-31 P3.3
PWM1
L
/AD3/PLAI[11]
J2-32 P3.2
PWM1
H
/AD2/PLAI[10]
J2-33 P3.1
PWM0
L
/AD1/PLAI[9]
J2-34 P3.0
PWM0
H
/AD0/PLAI[8]
J2-35 P0.2
PWM2
L
/BHE
J2-36 P0.6
T1/MRST/AE/PLAO[3]
J2-37 P0.0
CMP/
MS2/PLAI[7]
J2-38 P4.7
AD15/PLAO[15]
J2-39 P4.6
AD14/PLAO[14]
J2-40 P2.3
AE
J2-41 P0.1
PWM2
H
/BLE
J2-42 DGND
AN-744
Rev. A | Page 9 of 16
EXTERNAL MEMORY INTERFACE
A footprint for a 32 k × 16 SRAM, a 64 k × 16 Flash, and a
16-bit D-latch are provided on board because address and data
are multiplexed on the external bus.
The memory footprints are for a CY7C1020CV33 and
AT29LV1024. The latch footprint is for a 74LVT16373AGG.
Note that you can use different versions of the CY7C1020CV33
memory, with different access times. Wait states can be added in
the XMxPAR register to allow for interfacing to a slower
memory, if required.
CONNECTIONS
Table 4.
Connection Description
Controls RS, WS, and AE are the minimum control signals of any memory interface.
MS0 and MS1, memory select signals, are connected to the CE of the SRAM and the flash, respectively, to enable the
memory when necessary.
BHE and BLE allows the high or low byte of the 16-bit SRAM to be selected.
Data 16 bits of data AD[15-0] are directly connected from the ADuC7026 to the memory circuitry.
Addresses 16 bits of address AD[16-1] are connected from the ADuC702x to A[15-0] of the memory devices. AD[0] addresses a byte.
To address the 32 k of the SRAM only, 14-bit addresses are required.
15-bit addresses are required for the 64 k flash.
ADR [0:15]
VDDIO
VCC VSS
VSS
ADR0
ADR1
ADR2
ADR15
ADR14
ADR13
ADR12
ADR11
ADR10
ADR9
ADR8
ADR7
ADR5
ADR6
ADR4
ADR3
ADR0
ADR1
ADR2
ADR14
ADR13
ADR12
ADR11
ADR10
ADR9
ADR8
ADR7
ADR5
ADR6
ADR4
ADR3
AD0
AD1
AD2
AD14
AD13
AD15
AD12
AD11
AD10
AD9
AD8
AD7
AD5
AD6
AD4
AD3
ADR0
ADR1
ADR2
ADR14
ADR13
ADR15
ADR12
ADR11
ADR10
ADR9
ADR8
ADR7
ADR5
ADR6
ADR4
ADR3
AD0
AD1
AD2
AD15
AD14
AD13
AD12
AD11
AD10
AD9
AD8
AD7
AD5
AD6
AD4
AD3
00
01
02
015
014
013
012
011
010
09
08
07
05
06
04
03
46
47
37
12
27
22
23
45
44
28
29
30
31
32
34
35
36
38
40
39
42
43
2
3
4
20
19
18
17
15
14
13
11
10
7
9
6
5
5
4
3
19
11
33
12
34
41
17
6
40
39
20
21
24
25
26
27
42
44
43
18
2
7
8
9
37
36
38
35
32
31
30
29
16
14
15
13
10
A0
A1
A2
A15
A14
A13
A12
A11
A10
A9
A8
A7
A5
A6
A4
A3
I01
I02
I015
I014
I016
I013
I012
I011
I010
I09
I08
I07
I05
I06
I04
I03
A0
A1
A2
A14
A13
A12
A11
A10
A9
A8
A7
A5
A6
A4
A3
AD0
AD1
AD2
AD15
AD14
AD13
AD12
AD11
AD10
AD9
AD8
AD7
AD5
AD6
AD4
AD3
RSMS1
OE
WS
CE
WE
U6
AT29LV1024
U8
CY7C1020CV33-12
CE
OE
WE
BHE VSS
VCC
VCC
VSS
BLE
MS0
VDDIO
RS
WS
BHE
BLE
2
3
5
22
20
23
19
17
16
14
13
12
39
34
45
28
21
15
10
4
9
11
8
6
47
46
44
27
29
26
30
32
33
35
36
37
31
18
42
7
48
25
24
1
40
38
41
43
1D0
1D1
1D2
2D6
2D5
2D7
2D4
2D3
2D2
2D1
2D0
1D7
VCC
VCC
VCC
VCC
1LE
2LE
2OE
1OE
1D5
1D6
1D4
1D3
1Q0
1Q1
1Q2
2Q6
2Q5
2Q7
2Q4
2Q3
2Q2
2Q1
2Q0
1Q7
GND
GND
GND
GND
GND
GND
GND
GND
1Q5
1Q6
1Q4
1Q3
74LVT16373ADGG
U7
R23
0Ω
VDDIO
AE
0
5032-002
NOTES
1. THE FOOTPRINT FOR THE FLASH IS ON THE BOTTOM SIDE OF THE BOARD.
Figure 2. External Memory Connections
AN-744
Rev. A | Page 10 of 16
POTENTIOMETER DEMONSTRATION CIRCUIT
By using the sample code in pot.c located in the code example
folder on the accompanying CD, the variation in the
potentiometer resistance can be seen on the output LED.
Note that the internal and external reference are 2.5 V,
which gives an ADC input range of 0 V to 2.5 V in single-ended
mode. The potentiometer can give a voltage between 0 V and
AV
DD
= 3.3 V.
A
V
DD
A
V
DD
APPLICATION
CODE
DACADC
05032-003
Figure 3. Circuit Diagram of the RTD Circuit
AN-744
Rev. A | Page 11 of 16
SCHEMATIC
ANALOG INTERFACE
JTAG CONTROLLER
J3-1
J3-2
J3-3
J3-4
J3-5
J3-6
J3-7
J3-8
J3-9
J3-10
J3-11
J3-12
J3-13
J3-14
J3-15
J3-16
J3-17
J3-18
J3-19
J3-20
J3-21
J3-22
J3-23
J3-24
AVDD
AGND
VREF
DACREF
ADC0
ADC1
ADC2
ADC3
ADC4
ADC5
ADC6
ADC7
ADC8
ADC9
ADC10
ADC11
DIFF
VOCM
DAC0
DAC1
DAC2
DAC3
ADCNEG
AGND
ADC4
ADC5
ADC6
ADC7
ADC8
ADC9
ADC10
GNDREF
ADCNEG
DAC0
DAC1
DAC2
DAC3
TMS
TDI
P0.1
P2.3
P4.6
P4.7
P0.0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
P1.2
P1.3
P1.4
P1.5
P4.1
P4.0
IOVDD
IOGND
P1.6
P1.7
P2.2
P2.1
P2.7
P3.7
P3.6
XCLKI
XCLKO
P0.7
P2.0
P0.5
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
ADC3
ADC2
ADC1
ADC0
ADC11
DACVDD
AVD D
AVD D
AGND
AGND
DACGND
DACREF
VREF
REFGND
P4.5
P4.4
P4.3
P4.2
P1.0
P1.1
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
P0.6
TCK
TD0
P0.2
IOGND
IOVDD
LVDD
DGNG
P3.0
P3.1
P3.2
P3.3
P2.4
P0.3
P2.5
P2.6
RST
P3.4
P3.5
P0.4
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
U1
ADuC7026
J2–8
J2–9
J2–10
J2–11
J2–12
J2–13
P1.2
P1.3
P1.4
P1.5
P4.1
P4.0
J2–14
J2–15
J2–16
J2–17
J2–18
J2–19
J2–20
J2–21
J2–22
J2–23
P1.6
P1.7
P2.2
P2.1
P2.7
P3.7
P3.6
P0.7
P2.0
P0.5
J2–2
J2–3
J2–4
J2–5
J2–6
J2–7
P4.5
P4.4
P4.3
P4.2
P1.0
P1.1
J2–1
DGND
VDDIO
Y1
32.768kHz
AD8
AD9
AD10
AD11
AD12
AD13
AD6
AD7
WS
RS
J4-1
J4-2
J4-3
J4-4
J4-5
J4-6
J4-7
J4-8
J4-9
J4-10
J4-11
J4-12
J4-13
J4-14
J4-15
J4-16
J4-17
J4-18
J4-19
J4-20
TRST
TDI
TMS
TCK
TDO
NC
NC
NC
VDDIO
DIGITAL INTERFACE
VDDIO
C16
0.1µF
C17
0.1µF
C18
10µF
AVDD
AVDD
U4–C
C14
0.1µF
C15
10µF
U1 BYPASS CAPACITORS
C13
10µF
C12
0.1µF
V+
V–
8
4
VDDIO
C21
12pF
C20
12pF
VDDIO
VDDIO
DGND
J1–1
J1–2
J1–3
J1–4
UART
AVDD
R18
270Ω
P4.2
D2
VDDIO
VDDIO
IRQ0S4
RESET
S3
R17
1kΩ
SERIAL DOWNLOAD
S2
J2–24
P0.4
J2–25
J2–26
J2–27
J2–28
J2–29
J2–30
J2–31
J2–32
J2–33
J2–34
J2–35
J2–36
J2–37
J2–38
J2–39
J2–40
J2–41
J2–42
P3.5
P3.4
P2.6
P2.5
P0.3
P2.4
P3.3
P3.2
P3.1
P3.0
P0.2
P0.6
P0.0
P4.7
P4.6
P2.3
P0.1
DGND
AD0
AD1
AD2
AD3
MS1
AD4
AD5
BHE
MS0
AE
AD14
AD15
BLE
C19
470nF
R15
1kΩ
R24
100kΩ
VDDIO
U4-B
7
5
6
AD8606ARZ
R22
100kΩ
R21
100kΩ
VDDIO
AVDD
R14
0Ω
C10
10nF
C11
470nF
U4-A
C9 AND C10 NOT POPULATED
1
2
3
AD8606ARZ
R13
0Ω
C9
10nF
3
6
5
4
1
2
8
+IN
+OUT
V–
–OUT
AD8132
U3
V+
VOCM
–IN
C6
0.1µF
C5
10µF
+
AVDD
R8
348Ω
R10
60.4Ω
R11
60.4Ω
R9
348Ω
R5
348Ω
R6
348Ω
R7
24.9Ω
R4
49.9Ω
C4
0.1µF
J5–2
POWER SUPPLIES
J5–4
J5–1
J5–3
D4
C24
0.1µF
C23
10µF
U5
OUT IN
GND
21
37
SD
+
+
D3
R20
270Ω
VDDIO
AVD D
L1
R19
1.5Ω
C22
10µF
C3
0.1µF
C2
0.1µF
C1
10µF
AVDD
5
4
26
ADR291E
U2
+VIN
+VOUT
TRIM
GND
DEMO CIRCUIT
16
15
14
13
12
11
10
9
VREF
VOCM
POT
ADC3
N–
N+
ADC4
LED
AVDD
DEMO CIRCUIT
S1
SW8DIP
1
2
3
4
5
6
7
8
R1
CW
R2
100Ω
R3
200Ω
R12
270Ω
AVDD
D1
C7
22pF
C8
22pF
+
+
++
05032-004
R16
1kΩ
Figure 4. ADuC7026 Evaluation Board Schematic
AN-744
Rev. A | Page 12 of 16
Figure 5. ADuC7026 Evaluation Board Silkscreen
AN-744
Rev. A | Page 13 of 16
ADuC7026 EVALUATION BOARD PARTS LIST
Table 5.
Component Qty Part Description Order No. Mfg.
EVAL-ADuC7026QS
QuickStart PCB
1 PCB-1 2-sided, surface-mount PCB Analog Devices
PCB Stand-off 4 Stand-off Stick-on mounting feet 148-922 Farnell
U1 1 ADuC7026 MicroConverter (80-lead LQFP) ADuC7026CP Analog Devices
U2 1 ADR291 Band gap reference ADR291ER Analog Devices
U3 1 AD8132 Differential op amp AD8132ARM Analog Devices
U4 1 AD8606 Dual op amp, (8-pin SOIC) AD8606AR Analog Devices
U5 1 ADP3333 Fixed 3.3 V linear voltage regulator ADP3333ARM3.3 Analog Devices
U6 (Not populated) 0 AT29LV1024 64 k × 16 flash AT29LV1024
U7 (Not populated) 0 74LVT16373ADGG 16-bit D-latch 74LVT16373ADGG
U8 (Not populated) 0 CY7C1020CV33-12 32 k × 16 Static RAM CY7C1020CV33-12
Y1 1 32.768 kHz Watch crystal 971-3220 Farnell
S1 1 SW\8DIP 8-way DIP switch GH7242-ND Digikey
S2, S3, S4 3 Push button switch PCB-mounted push button switch 177-807 Farnell
D1, D2, D3 3 LED 1.8 mm miniature LED 359-9954 Farnell
D4 1 PRLL4002 Diode BAV103TPMSCT-ND Digikey
C1, C5, C13, C15,
C18, C22, C23
7 10 μF Surface-mount tantalum capacitor, Taj-B case 197-130 Farnell
C2 to C4, C6, C12,
C14, C16, C17,
C24 to C31
16 0.1 μF Surface-mount ceramic capacitor, 0603 case 317-287 Farnell
C7, C8 2 22 pF Surface-mount ceramic capacitor, 0603 case 722-005 Farnell
C9, C10 2 10 nF Surface-mount ceramic capacitor, 0603 case 301-9561 Farnell
C11, C19 2 470 nF Surface-mount ceramic capacitor, 0603 case 318-8851 Farnell
C20, C21 2 12 pF Surface-mount ceramic capacitor, 0603 case 721-979 Farnell
R1 1
10 kΩ
potentiometer
0.25W, 4 series, (4 mm × 4 mm square)
TS53YJ 10K 20% TR
(Lead free)
Vishay
R2 1 100 Ω Surface-mount resistor, 0603 case 933-2375 Farnell
R3 1 200 Ω Surface-mount resistor, 0603 case 933-2758 Farnell
R4 1 49.9 Ω Surface-mount resistor, 0805 case 311-49.9HRCT-ND Digikey
R5, R6, R8, R9 4 348 Ω Surface-mount resistor, 0603 case 311-348HRCT-ND Digikey
R7 1 24.9 Ω Surface-mount resistor, 0805 case 311-24.9HRCT-ND Digikey
R10, R11 2 60.4 Ω Surface-mount resistor, 0805 case 311-60.4HRCT-ND Digikey
R12, R18, R20 3 270 Ω Surface-mount resistor, 0603 case 933-0917 Farnell
R13, R14, R23 3 0 Ω Surface-mount resistor, 0603 case 933-1662 Farnell
R15, R16, R17 3 1 kΩ Surface-mount resistor, 0603 case 933-0380 Farnell
R19 1 1.5 Ω Surface-mount resistor, 0603 case 9331832 Farnell
R21, R22, R24 3 100 kΩ Surface-mount resistor, 0603 case 933-0402 Farnell
L1 1 Ferrite bead Surface-mount inductor, 1206 case 952-6862 Farnell
J1 1 4-pin header 4-pin, 90º single-row header TSM-104-02-T-SH Samtec
J2 1 42-pin header 42-pin, straight single-row header TSM-121-01-T-DV Samtec
J3 1 42-pin header 24-pin, straight single-row header TSM-124-01-T-SV Samtec
J4 1 20-pin header 20-pin, connector HTST-110-01-L-DV Samtec
J5 1 Power socket
PCB mounted socket
(2 mm pin diameter)
KLD-SMT2-0202-A Kycon
AN-744
Rev. A | Page 14 of 16
NOTES
AN-744
Rev. A | Page 15 of 16
NOTES
AN-744
Rev. A | Page 16 of 16
NOTES
©2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
AN05032-0-1/07(A)
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Analog Devices ADuC7026 Application notes

Analog Devices
Brand
Analog Devices
Model
ADuC7026
Type
Application notes

Analog Devices ADuC7026 is a low-power, 16-bit microcontroller with an 8-channel, 12-bit ADC, a voltage reference, and a comparator. It is ideal for applications that require high precision and low power consumption, such as portable medical devices, industrial controls, and data acquisition systems.

The ADuC7026 has a number of features that make it well-suited for these applications, including:

  • A high-performance 16-bit CPU with a clock speed of up to 40 MHz
  • An 8-channel, 12-bit ADC with a conversion time of 10 μs
  • A 2.5 V voltage reference with a temperature drift of 10 ppm/°C
  • A comparator with a threshold voltage that can be set to any value between 0 and 2.5 V
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