Spectrum Digital AppBox C21 User manual

AppBox C21 System User’s Guide 1
AppBox
Specializes in
designing with
Microchip
products
AppBox C21
System User’s
Guide

AppBox C21 System User’s Guide 2
AppBox
Notice !
Spectrum Digital, Inc (SDI) provides the enclosed product under the following conditions:
The user/customer assumes ALL responsibility and liability for the proper use, storage, and safe handling
of the product. Further, the user indemnifies SDI from all claims arising from the use, installation, storage,
and handling of the product. Due to the flexibility and open construction of the product, it is the user’s
responsibility to take all appropriate precautions with regard to powering, attachment of cables,
connection to other equipment, and electrostatic discharge.
Except to the extent of the indemnity set forth above, neither party shall be liable to the other for any
indirect, special, incidental, or consequential damages.
SDI assumes no liability for applications assistance, customer product design, system and software
performance, or infringements of patents or services described herein.
No license is granted under any patent right or other intellectual property right of SDI covering or relating
to any machines, process, software, or combination in which such SDI products or services might be or
are used.
SDI currently deals with a variety of customers for products, and therefore our arrangement with the
reseller, customer, or user is not exclusive.
Please refer to the product web page on the SDI web site for warranty period.
The warranty and return policy are described on the SDI web site.
Mailing address:
Spectrum Digital, Inc
PO Box 1559
Sugar Land, TX. 77487-1559
Web site: www.spectrumdigital.com
Sales: [email protected]
Support: [e-mail]
Copyright Spectrum Digital Inc, © 2020
519098-4001

AppBox C21 System User’s Guide 3
AppBox
Table of Contents
Section Title Page
1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 AppBox C21 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 AppBox C21 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 What’s Included In The AppBox C21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 AppBox C21 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 AppBox C21 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6 AppBox C21 Communication Expansion . . . . . . . . . . . . . . . . . . . . . . . 6
1.7 AppBox C21 Software Development Tools . . . . . . . . . . . . . . . . . . . . . . . 6
2.0 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Attaching Power to the AppBox C21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Installation of AppIO Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Attachment of the Distribution Box to the AppBox C21 . . . . . . . . . . . . . . . . . 9
2.4 Installation of Atmel-ICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.0 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.1 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1 J1, Power Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.1.2 J2, RS485 / CAN / LIN Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.1.3 J6, Cortex-M Debug Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.1.4 AppIO Module Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.4.1 EXT1, AppIO Module 1 Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.1.5.2 EXT2, AppIO Module 2 Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.1.6.3 EXT3, AppIO Module 3 Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.2 Jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.3 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.4 LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.5 Test Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.0 Physical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.0 Mechanical Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.0 Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

AppBox C21 System User’s Guide 4
AppBox
1.0 Introduction
This document describes the features of the AppBox C21. The AppBox C21 is designed to be used in an
industrial environment with a CAN, RS-485, or LIN interface and provide flexible, modular I/O (AppIO) for
specific applications. These AppIO Modules allow customized solutions to be integrated for a wide variety of
applications that need to go into a CAN, RS-485, or LIN communications environment.
1.1 AppBox C21 Features
This AppBox C21 has the following features:
Atmel ATSAMC21J18A processor (ARM Cortex-M0+), maximum frequency 48 MHz.
Operates on +12 to +24 volts DC, uses less than 500 Ma. at +12
CAN interface for industrial systems
RS-485 communications for industrial systems
LIN interface for automotive systems
Communication interface expansion via Distribution Box (sold separately)
Modular I/O expansion via up to three (3) AppIO Modules, Atmel X PLAINED compatible
Fully enclosed system with knock out panels for AppIO Modules (sold separately)
Convenient enclosure mounting holes
Vented enclosure for cooling
Front panel push button switch
Front panel programmable LED
Atmel-ICE debug header present for development
Operates 0 - +70C
AppIO
Module #1
AppIO
Module #3
AppIO
Module #2
RS485/
CAN/
LIN
Power
+12-24 VDC Interface #3
Interface #1
Interface #2
User Defined
AppBox C21 Block Diagram
LED
Push
Button
Switch Comms
Select
Switch
Atmel-ICE
Header
ATSAMC21J18A
uP
C21 CPU BOARD
LED1
SW1
J2
J1
EXT1
EXT2
EXT3

AppBox C21 System User’s Guide 5
AppBox
1.2 AppBox C21 Applications
The AppBox C21 can be used in the following applications:
Low cost process/industrial control
Automation
Metering
Motor control
Systems operating in noisy environments
Communications converter (CAN-RS485-LIN)
Operates with industrial voltage levels
Reconfigurable applications with AppIO Modules
Entry level microcontroller educational tool
1.3 What’s Included In the AppBox C21
The Spectrum Digital AppBox C21 product (Part/SKU #: 703909-0001) includes:
AppBox C21 in anti-static bag
Terminal block header for power input
Product information card
NOTE: This product does not include any software or drivers. Development tools (Atmel-ICE and
Software code generation suite) can be obtained from Microchip/Atmel at:
https://www.microchip.com/development-tools/.
1.4 AppBox C21 Front Panel
The features of the front panel on the AppBox C21 are shown in the figure below:
1.5 AppBox C21 Accessories
The following accessories for the AppBox C21 can be ordered from Spectrum Digital or authorized resellers:
Accessory Description Part/SKU Number
AppBox Power Supply with cable,
110/220 VAC to 12V, 1.5A 703925-0001
Distribution Box 703924-0001
AppBox cable 703923-0001
RS485 Cable 703917-0001
CAN Cable 703912-0001
LIN cable 703922-0001
J1
J2
LED1 AppBox C21 Front Panel
SW1

AppBox C21 System User’s Guide 6
AppBox
1.6 AppBox C21 Communication Expansion
The J2 connector on the AppBox C21 presents multiple communication interfaces. The standard factory
cables only support one interface at a time. To have access to multiple communication interfaces, a
Distribution Box (Part/SKU #: 703924-0001) and AppBox cable (Part/SKU #:703923-0001) are required.
The Distribution Box expands the J2 connector to four (4) images of the AppBox C21 J2 connector. The
AppBox cable bridges all signals on the AppBox C21 J2 connector to a connector on the Distribution Box.
Be aware that one (1) of the Distribution Box connectors will be used for the AppBox bridging cable leaving
three (3) connectors available for communication interfaces. All AppBox interface cables that can used on the
AppBox J2 connector are also compatible with the Distribution Box.
The user should enable all interfaces they want to use with the Distribution Box by setting the switch positions
on Switch SW2, positions 1, 2, or 3. See section 3.3.
The AppBox C21 and Distribution Box system configuration is shown in the figure below:
1.7 AppBox C21 Software Development Tools
The AppBox C21 is compatible with the software and hardware development tools from Microchip/Atmel.
These tools are described on the Microchip/Atmel website:
https://www.microchip.com/development-tools/
These tools include the following:
Editor
Compiler/assembler/linker
Libraries
Operating System
Debugger
JTAG Emulator
RS485/
CAN/
LIN
RS485/
CAN/
LIN
RS485/
CAN/
LIN
AppBox C21 with Distribution Box
Distribution Box
AppBox C21
J2 Connector
AppBox Cable

AppBox C21 System User’s Guide 7
AppBox
2.0 Installation
2.1 Attaching Power to the AppBox C21
Power can be provided to the AppBox C21 by two different means; the AppBox power supply with cable
(Part/SKU #: 703925-0001), or wiring the 2 position terminal block header (included with AppBox C21) that
plugs into the C21 CPU Board’s power input connector. See the figure below.
Listed below are the steps to install the terminal block header power connector (included in kit) into the
AppBox C21.
1. Cut 2 pieces of wire (preferably 1 red for positive-VIN, 1 black for negative-DGND) to the desired
length for your application. This wire should be 22 gauge or heavier
2. Strip ¼ inch (6-7 mm) of insulation from one end of each wire.
3. Position the terminal block header on a flat surface with the key stubs up and away from you. See
the figure below.
4. Insert the negative/DGND wire (black) into the left wire hole and tighten the screw.
5. Insert the positive/VIN wire (red or black with stripe) into the right wire hole and tighten the screw.
6. The terminal header should look like the figure below.
7. Pull/tug on the wires to insure they are secure in the terminal block.
AppBox Power Connector
Positive
VIN
Negative
DGND
Terminal Block Header
Wired Terminal Block Header
Positive
VIN
Negative
DGND
Screw
Screw

AppBox C21 System User’s Guide 8
AppBox
8. Attach the loose end of the wires to a +12 – 24 VDC power source. Be sure of the polarity. This
power source should supply at least 1 amp of current. This requirement will vary
depending on the current requirements of the C21 CPU Board and the AppIO Modules.
9. Turn on the power source.
10. With a multi-meter or oscilloscope measure the voltage at the terminal block header to verify
+12 -24 VDC is present. Place the meter/scope probes on the 2 screws to measure.
11. Turn off the power source
12. Insert the terminal block header into the power input of the AppBox C21.
13. Turn on the power source.
2.2 Installation of AppIO Modules
Listed below are the steps to install AppIO Modules in the AppBox C21:
1. Remove ALL power to the AppBox enclosure
2. Remove all interface connections attached to the installed AppIO Modules
3. Remove the CAN/RS-485/LIN cables attached to the C21 processor board
4. Turn the AppBox over and remove the 2 screws from the bottom of the enclosure as shown
below
5. Turn the AppBox back over (label showing) and lift the top off the enclosure being careful not to
lose the knockout panels
6. If necessary remove one or more existing AppIO Modules and associated knockout panels by
unscrewing the 2 screws
7. If the AppIO modules require configuration or jumper settings, do it now.
8. Plug the new AppIO Module(s) into EXT1, EXT2, or EXT3 on the C21 CPU Board
Screws
A
pp
Box Bottom Screw Locations
A
pp
IO Module
A
ttached to C21 CPU Board
C21 CPU
Board AppIO Module
AppIO Knockout
Panel
Screw
Screw

AppBox C21 System User’s Guide 9
AppBox
9. Insert the included knock out panel associated with this AppIO Module
10. Secure the AppIO Modules to the AppBox base with the 2 provided screws
11. Insert the blank knock out panels in any unused positions
12. Place the cover back over the C21 CPU Board and AppIO Modules. Make sure the cover
closes tight on both sides
13. Turn the AppBox over and insert the 2 screws back in and tighten until snug, do not over
tighten/strip the screws
14. Re-attach the CAN/RS-485/LIN connections to the processor board
15. Re-attach all interface connections to the AppIO Modules
16. Apply power to the AppBox C21
2.3 Attachment of Distribution Box to the AppBox C21
Listed below are the steps to attach the Distribution Box (Part/SKU #: 703924-0001) to the AppBox C21:
1. Remove ALL power to the AppBox C21 enclosure
2. Remove any communication cables attached to the J2 connector on the AppBox C21
3. Plug one end of the AppBox cable (Part/SKU #: 703923-0001) into the J2 connector on the
AppBox C21
4. Plug the other end of the AppBox cable into one of the connectors on the Distribution Box
5. Plug the desired communication cables into the Distribution Box
6. Make all other connections before powering
7. Apply power to the AppBox C21
A
pp
Box C21 Connected to Distribution Box
AppBox
AppBox Cable
Distribution Box
A
pp
Box C21 with A
pp
IO Module Installed
AppIO Module
Connector
AppIO Knockout
Panel

AppBox C21 System User’s Guide 10
AppBox
2.4 Installation of Atmel-ICE emulator
Listed below are the steps to install Atmel-ICE emulator:
1. Remove ALL power to the AppBox C21 enclosure
2. Remove all interface connections attached to the AppIO Modules
3. Remove the CAN/RS-485/LIN connections to the processor Module
4. Turn the AppBox over and remove the 2 screws from the bottom of the enclosure as shown
below
5. Turn the AppBox back over (label showing) and lift the top off the enclosure being careful not to
lose the knockout panels
6. Plug the emulator end of the ribbon cable into the “SAM” Port on the emulator
7. Plug in the Atmel-ICE debug into connector J6 on the AppBox C21 CPU board. Visually inspect
the connection to insure all the board pins are in the female cable connector.
8. Re-attach the CAN/RS-485/LIN connections to the processor board
9 . Re-attach all interface connections to the AppIO Modules
10. Apply power to the AppBox C21
11. Start debug session on the host computer
Screws
A
pp
Box Bottom Screw Locations
C21 CPU Board
Atmel-ICE Attached to A
pp
Box C21 CPU Board
J6 Connector
RED Wire
SAM Port
Atmel-ICE

AppBox C21 System User’s Guide 11
AppBox
3.0 Interfaces
This section describes the interfaces on the AppBox C21 CPU Board. These interfaces include the
connectors, jumpers, switches, LEDs, and test points.
The location of each of these interfaces is shown in the figure below:
SW1
SW2
J1
EXT1
EXT3
EXT2
J6
J2
TP2 TP3
TP1
TP4
LED1
AppBox C21 CPU Board Interfaces

AppBox C21 System User’s Guide 12
AppBox
The table below lists all the interfaces on the AppBox C21 CPU Board.
AppBox C21 CPU BOARD INTERFACES
INTERFACE NAME TYPE OF INTERFACE
J1 Connector for power input
J2 Connector for RS485/CAN/LIN
J6 Connector for header 5x2
Cortex-M Debug
EXT1 Connector to AppIO Module
EXT2 Connector to AppIO Module
EXT3 Connector to AppIO Module
JP1 SMT jumper(bottom)
JP2 SMT jumper(bottom)
JP3 SMT jumper(bottom)
JP4 SMT jumper(bottom)
JP5 SMT jumper(bottom)
JP6 SMT jumper(bottom)
JP7 SMT jumper(bottom)
JP8 SMT jumper(bottom)
JP9 SMT jumper(bottom)
SW1 Pushbutton switch
SW2 4 position DIP switch
LED1 Green LED
TP1 Test point
TP2 Test point
TP3 Test point
TP4 Test point
3.1 Connectors
The following section describes the connectors on the AppBox C21 CPU Board.
INTERFACE NAME TYPE OF INTERFACE MATING CONNECTOR
J1 Connector for power input,
2 position
Amphenol Anytek
Terminal Block Plug, 2 pos
TJ0231530000G
TS02315A0000G
J2 Connector for RS-485/CAN/LIN,
10 position, 2 x 5
Molex 10 Position Rectangular
Housing Connector Receptacle
Natural 0.165" (4.20mm)
0039012100, 0039000038
J6 Connector for header 5x2 Cortex-M Debug tail
EXT1 Connector to AppIO Module #1,
20 position, 2 x 10
EXT2 Connector to AppIO Module #2,
20 position, 2 x 10
EXT3 Connector to AppIO Module #3,
20 position, 2 x 10

AppBox C21 System User’s Guide 13
AppBox
3.1.1 J1, Power Connector
This section describes J1, the power connector. Shown below is a physical diagram of the J1 connector.
The following table shows the signals present on the J1 connector.
J1, Power Connector
Pin number Signal name
1 DGND
2 VIN, (+12-24 VDC)
Pin 1, DGND Pin 2, VIN
J1, Power Connector
(card edge view)

AppBox C21 System User’s Guide 14
AppBox
3.1.2 J2, RS485 / CAN / LIN Connector
This section describes J2, the RS485 / CAN / LIN connector. The diagram below shows the physical layout
of the J2 connector.
The following table shows the signals present on the J2 connector.
J2, RS-485 / CAN / LIN Connector
Pin number Signal name
1 RS485_A
2 RS485_B
3 DGND
4 CAN_H
5 CAN_L
6 VDD_5V if JP7 shorted
7 DGND
8 LIN_PWR In
9 LIN
10 DGND
3.1.3 J6, Cortex-M Debug Connector
The following table shows the signals on the J6 connector.
J6, Cortex-M Debug Connector
Pin number Signal name
1 VDD_3V3, +3.3 volts
2 PA31_SWDIO
3 DGND
4 PA30_SWCLK/TCK
5 DGND
6 No Connect
7 No Connect
8 No Connect
9 DGND
10 RESETn
Pin 5, CAN_L
J2, RS485/CAN/LIN Connector
Pin 6, Pin 2,Pin 10, DGND
Pin 1, RS485
_A
(card edge view)

AppBox C21 System User’s Guide 15
AppBox
3.1.4 AppIO Module Connectors
The AppBox C21 CPU Board has 3 connectors which allow the AppBox C21 to be customized to meet
specific application requirements. By using function specific AppIO Modules, the user can tailor their system
configuration to meet their unique requirements. The AppIO Modules can be plugged into any of the
3 connectors (EXT1, EXT2, EXT3). These 3 connectors are 20 pin, 2 x 10 double row, right angle
connectors with pins on 0.1 inch (2.54 mm) centers.
Note: The user should be aware that several signals from the AppBox C21 CPU are shared and present on
all 3 connectors. If the signals are used by one connector (AppIO Module) they should not be used on the
other connectors.
The following diagram shows the physical layout of the EXT1, EXT2, and EXT3 connectors.
Pin 1
AppBox C21 CPU Board AppIO Module Connector
(card edge view)
Pin 2
Pin 19
Pin 20
Circuit Board

AppBox C21 System User’s Guide 16
AppBox
3.1.4.1 EXT1, AppIO Module Connector
The following table shows the signals present on the EXT1 connector.
EXT1, AppIO Module Connector
Pin # Signal Name Function Shared Functionality
1 Pin 2, JP1, VDD_5V if shorted +5 volts to AppIO Module if
shorted VDD_5V
2 DGND Ground Ground
3 PB09_ADC(P) A/D converter, alternatively
positive part of differential ADC
4 PB08_ADC(N) A/D converter, alternatively
negative part of differential ADC
5 PA20_GPIO General purpose I/O
6 PA21_GPIO General purpose I/O
7 PB12_PWM(P) PWM, alternatively positive part
of differential PWM
8 PB13_PWM(N)
PWM, alternatively negative part
of differential PWM
9 PB14_IRQ/GPIO Interrupt request line and/or
GPIO
10 PB15_SPI_SS_B/GPIO Slave select for SPI and/or GPIO
11 PA12_TWI_SDA Data line for I2C interface, always
implemented, bus type Pin 11 on EXT2, EXT3, Pin 5, U2
12 PA13_TWI_SCL Clock line for I2C interface,
always implemented, bus type Pin 12 on EXT2, EXT3, Pin 6, U2
13 PA23_UART_RX Receiver line of target device
UART Pin 13 on EXT2, EXT3
14 PA22_UART_TX
Transmitter line of target device
UART Pin 14 on EXT2, EXT3
15 PA17_SPI_SS_A Slave select for SPI
16 PA18_SPI_MOSI
Master out slave out line of serial
peripheral interface, always
implemented, bus type
17 PA16_SPI_MISO Master in slave out line of serial
peripheral interface, always
implemented, bus type
18 PA19_SPI_SCK Clock for serial peripheral interface, always implemented,
bus type
19 DGND Ground Ground
20 VDD_3V3 Power for the AppIO Module Power for the AppIO Module

AppBox C21 System User’s Guide 17
AppBox
3.1.4.2 EXT2, AppIO Module Connector
The following table shows the signals present on the EXT2 connector.
EXT2, AppIO Module Connector
Pin # Signal Name Function Shared Functionality
1 Pin 2, JP2, VDD_5V if shorted +5 volts to AppIO Module if
shorted VDD_5V
2 DGND Ground Ground
3 PA08_ADC(P) A/D converter, alternatively
positive part of differential ADC
4 PA09_ADC(N)
A/D converter, alternatively
negative part of differential
ADC
5 PA10_GPIO General purpose I/O
6 PA11_GPIO General purpose I/O
7 PB30_PWM(P) PWM, alternatively positive
part of differential PWM
8 PB31_PWM(N)
PWM, alternatively negative
part of differential PWM
9 PB16_IRQ/GPIO Interrupt request line and/or
GPIO
10 PB17_SPI_SS_B/GPIO Slave select for SPI and/or
GPIO
11 PA12_TWI_SDA Data line for I2C interface,
always implemented, bus type Pin 11 on EXT1, EXT3, Pin 5, U2
12 PA13_TWI_SCL Clock line for I2C interface,
always implemented, bus type Pin 12 on EXT1, EXT3, Pin 6, U2
13 PA23_UART_RX Receiver line of target device
UART Pin 13 on EXT1, EXT3
14 PA22_UART_TX Transmitter line of target
device UART Pin 14 on EXT1, EXT3
15 PB03_SPI_SS_A Slave select for SPI
16 PB00_SPI_MOSI Master out slave out line of serial peripheral interface,
always implemented, bus type
17 PB02_SPI_MISO Master in slave out line of serial peripheral interface,
always implemented, bus type
18 PB01_SPI_SCK Clock for serial peripheral
interface, always implemented,
bus type
19 DGND Ground Ground
20 VDD_3V3 Power for the AppIO Module Power for the AppIO
Module

AppBox C21 System User’s Guide 18
AppBox
3.1.4.3 EXT3, AppIO Module Connector
The following table shows the signals present on the EXT3 connector.
EXT3, AppIO Module Connector
Pin # Signal Name Function Shared Functionality
1 Pin 2, JP3, VDD_5V if shorted +5 volts to AppIO Module if
shorted VDD_5V
2 DGND Ground Ground
3 PB07_ADC(P) A/D converter, alternatively
positive part of differential ADC
4 PB06_ADC(N) A/D converter, alternatively
negative part of differential ADC
5 PB04_GPIO General purpose I/O
6 PB05_GPIO General purpose I/O
7 PA14_PWM(P) PWM, alternatively positive part
of differential PWM 16 Mhz. crystal, Y2
8 PA15_PWM(N)
PWM, alternatively negative part
of differential PWM Green LED, 16 Mhz. crystal, Y2
9 PA28_IRQ/GPIO Interrupt request line and/or
GPIO SW1
10 PA27_SPI_SS_B/GPIO Slave select for SPI and/or GPIO
11 PA12_TWI_SDA Data line for I2C interface, always
implemented, bus type Pin 11 on EXT1, EXT2, Pin 5, U2
12 PA13_TWI_SCL Clock line for I2C interface,
always implemented, bus type Pin 12 on EXT1, EXT2, Pin 6, U2
13 PA23_UART_RX Receiver line of target device
UART Pin 13 on EXT1, EXT2
14 PA22_UART_TX
Transmitter line of target device
UART Pin 14 on EXT1, EXT2
15 PA02_SPI_SS_A Slave select for SPI
16 PB00_SPI_MOSI
Master out slave out line of serial
peripheral interface, always
implemented, bus type
17 PB02_SPI_MISO Master in slave out line of serial
peripheral interface, always
implemented, bus type
18 PB01_SPI_SCK Clock for serial peripheral interface, always implemented,
bus type
19 DGND Ground Ground
20 VDD_3V3 Power for the AppIO Module Power for the AppIO
Module

AppBox C21 System User’s Guide 19
AppBox
3.2 Jumpers
This section describes the jumpers on the AppBox C21 CPU board. All jumpers are located on the bottom
side of the circuit board. All jumpers are surface mount jumpers. The figure below shows the location of each
jumper.
JP2
JP6
JP4
JP5
JP7
JP1
JP9
JP8
JP3
AppBox C21 CPU Board Jumper Positions

AppBox C21 System User’s Guide 20
AppBox
The table below describes the jumpers on the AppBox C21 CPU Board.
JUMPER
NAME POSITION DESCRIPTION FACTORY SHIPPED POSITION
JP1 Installed = +5 V power to pin 1, EXT1 Installed
JP2 Installed = +5 V power to pin 1, EXT2 Installed
JP3 Installed = +5 V power to pin 1, EXT3 Installed
JP4 Installed = connects PA04_WP to Pin 7, U2, WP3
EEPROM write protect enable Open – see warning 1
JP5 Installed = connects VDD_3V3 to
PA05_WAKE/FAULT, and Pin3, U5
LIN WAKE/FAULT enable Installed
JP6 Installed = connects DGND to Pin 7, U2, WP3
EEPROM write protect disable Installed – see warning 1
JP7 Installed = connect VDD_5V to Pin 1, J2,
+5 volt output Open
JP8 Installed = connects PA14_XIN to PA14_PWM(P)
XTAL/PWM option Installed
JP9 Installed = connects PA15_XOUT to
PA14_PWM(N), XTAL/PWM option Installed
WARNING 1 !
Jumpers JP4 and JP6 are used in the same circuit. Only 1
should be installed. If both are installed the circuit could be
damaged.
!