RCAT -1A Revision A3 System Manual

Robotic system control board

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RCAT-1A Rev A3 Designer's manual

Serious Power for the Serious Designer

RCAT

Robotic System Control Board

Serious Power for the Serious Designer

System designer's manual

Current Version: RCAT-1A Revision A3

Robot Circuits, LLC

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Summary of Contents for RCAT RCAT-1A Revision A3

Page 1: Rcat
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer RCAT Robotic System Control Board Serious Power for the Serious Designer System designer’s manual Current Version: RCAT-1A Revision A3 Robot Circuits, LLC sales@robotcircuits.com support@robotcircuits.com Copyright © 2015 Robot Circuits, LLC...
Page 2: Table Of Contents
RCAT ....................................1 Robotic System Control Board ............................1 Introduction ..................................5 So what in the world does “RCAT™”mean? ........................5 What are we trying to do that other boards cannot? ....................6 RCAT™ Board specifics ..............................8 Power System ................................8 Schematic ................................
Page 3 Schematic .................................. 40 Free RS232 Channel ............................... 41 Ethernet System ................................41 Programming IDE (interactive Development Environment) ..................43 RCAT™ Startup Solution Software ..........................43 In-Circuit Emulator ..............................43 Demonstration Software ..............................44 RCAT™ Specifications ..............................45 Schematic Diagram ................................ 46...
Page 4 Serious Power for the Serious Designer Warranties (a) Robot Circuits, LLC warrants for a period of one (1) year from the date of sale that the RCAT™ Control Board conforms to and will perform according to the Specifications. (b) Robot Circuits, LLC shall not be liable for any defects caused by abuse, neglect, improper use, installation, or modification of the RCAT™, nor as a result of any customer design or use involving the attachment of any devices, testing apparatus, or other hardware.
Page 5: Introduction
Serious Power for the Serious Designer Introduction Welcome to the world of RCAT™ – We here at Robot Circuits believe you will find that the RCAT™ control board is simply the most versatile, powerful, easy to use, and cost-effective control board on the market today.
Page 6: What Are We Trying To Do That Other Boards Cannot
One of the major features of the RCAT board is its rich array of communications options. All totaled there are 14 different serial interfaces available. Although only a subset of these is available at any one time, the flexibility of the communications system allows you to interface with almost any serial device you can imagine.
Page 7 This software is written with Atmel’s Atmel Studio™ in mind. All that is required to get you up and running is the RCAT™ control board, a connection to an appropriate power source, a PC capable of connecting to an ICE (in-circuit-emulator), an ICE (in-circuit-emulator) like the ATATMEL-ICE™,...
Page 8: Rcat™ Board Specifics
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer RCAT™ Board specifics Power System The power input schematic is shown in Figure 1 below: Schematic Figure 1 The power input connector, J3, allows several configurations and options for power to the board. The simplest and most preferable is shown in Figure 2.
Page 9 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Optionally, you can connect a shorting wire in place of the switch if you will be controlling the RCAT™ power from the power supply itself. The RCAT™ can be fitted with an optional onboard 5Vdc regulator (U4) for cases where you do not have 5Vdc already available.
Page 10: Major Subsystems
Major Subsystems The RCAT™ control board comprises several major subsystems. Some of these subsystems are broken out to connectors on the board for access by external user hardware. Others are not. Still others have access to the outside world through interim circuitry.
Page 11 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Figure 6 Other ports that provide direct access are presented at other connectors that are configured for use by the alternate port purposes. For example, connector J4 provides direct access to ports PF4, PF5, PF6, PF7 and the CPU reset input.
Page 12 PL1 as inputs, and installing JP28 and/or JP29, thus bringing connection to the gates out to J5. The third and final type of subsystem on the RCAT™ board is what we call a “bussed” subsystem. The primary system of this type is the two-wire-interface (TWI) subsystem.
Page 13 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer A complete list of all the subsystems on the RCAT™ is presented below: Subsystem Name Type Access Connector Description And Associated Jumpers Dedicated Onboard Green/Yellow LED controlled by ports...
Page 14 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Subsystem Name Type Access Connector Description And Associated Jumpers ADC AREF Direct If an external AREF supply is desired for use in the Analog-to-digital system, it may be injected at J15 pin 1.
Page 15 It is up to the user to provide adequate heat sink. The RCAT™ has an onboard 3.3Vdc regulator for powering the onboard chips and systems requiring 3.3Vdc. This voltage is also available at several points on the board for use by external systems.
Page 16: Subsystems - Detailed Discussion
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Subsystems – Detailed discussion In this section each of the above subsystems is discussed in more detail, including schematics to help you understand the subsystem design and hopefully guide you to an understanding of how to use each.
Page 17: System Clock
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer System Clock The onboard 16MHz crystal provides the CPU timing reference. Schematic Figure 11 Notes Although rare, it is possible to “brick” the ATMega™ chip by improperly setting clock values in the programming apparatus and even sometimes, again, very rarely, as a result of improper voltages or signals being applied to numerous ports on the CPU.
Page 18: Notes
128Kbytes of external static RAM are available to be used by the CPU. The ATMega™ 2560 only directly addresses 64Kbytes. In order to make all 128Kbytes available, the RCAT™ board uses port PJ7 as address line A16. The GCC compiler can be configured to utilize this RAM in a variety of ways. Please consult the documentation for the IDE to learn the various possibilities.
Page 19: Notes
Vcc. Also note the 3.3Vdc to 5Vdc level shifters (Q1/Q2) enable the connection of 3.3Vdc TWI devices to J2 pins 5 and 7. The example software solution provided with your RCAT™ board configures the TWI for operation at 400KHz, so keep this in mind when connecting your device(s) and using the example solution provided.
Page 20: Spi Interface
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer The example software solution provided with your RCAT™ includes code to read this device and calculate pitch and roll information. Of course, much more complex data manipulation is possible (see the Analog Devices datasheet for details), but this example will provide you with the basic methods for reading and writing the various registers on the device.
Page 21: Adc Aref
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer ADC AREF Most applications will do fine using the CPU’s internal Vref for analog to digital conversion. For those applications requiring an external reference, access to the AREF is provided as shown in the schematic below.
Page 22: Mosfet Drivers
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Mosfet Drivers One feature missing on virtually every other robotic control board we know of is the ability to drive higher- current devices from the board without the addition of extra add-on boards.
Page 23 This example shows the use of mosfet Q3 with the return line of the external power source tied to J5 pin 32-C which connects the return line to the RCAT™ ground at a point very close to the Q3 source pin (see the yellow arrows).
Page 24: Alternatives For Controlling The Mosfets
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Alternatives for controlling the mosfets Notice the schematic below that the CPU port PL0 directly controls Q3: Figure 21 Now notice in the diagram below that PL0 also connects to jumper JP28 which then goes to J5. This opens the option of controlling the mosfet from the CPU or from an external source.
Page 25: Direct I/O Access
Direct I/O Access As noted previously, there are many CPU ports that are broken out directly to various points on the RCAT™ control board. The circled connectors in the image below show all the points where direct access is available: Figure 23 Copyright ©...
Page 26: Primary I/O Connector
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Primary I/O Connector First we will discuss connector J5 which we call the Primary I/O connector. On the schematic you may see: Figure 24 This indicates that connector J5 is a 3-row connector with rows A, B, and C. These row designators map to the board as shown above.
Page 27: Spi Connector
As shown, J1 gives you direct access to CPU ports PB1, PB2, and PB3 along with Vcc, /RST, and GND access. USART 0 There are no direct connection paths between USART0 and any connector on the RCAT™. All access to USART0 is peformed through the USB, RS232 or RS422/485 interfaces.
Page 28: 3.3 Volt Input/Output
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Figure 27 As shown above, J14 is a 3-row header with each row having all its pins tied together. This allows wire-or’ing of capable devices as described later in the USART 2 section. When not using this function, if you follow the bold red line you will see that J14 row A pins eventually find their way to CPU port PH0 which is also the USART 2 RXD line.
Page 30: Usart 3 Port - J8
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer 74VLC4245A Octal dual supply translating transceiver (3-state) Figure 30 While the 3.3Vdc to 5Vdc level translators ARE bidirectional, they ARE NOT TRANSPARENT…..the DIR inputs on each translator must be set for the correct direction of signal flow. Referring to Figures 28, 29 and 30 above, with the shunts installed as instructed, we see (following the violet line) J7 pin 1 reaching IC U8 on pin 20 which is the B2 pin on the translator chip.
Page 31: Schematic
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Refer to Figure 31 below: Schematic Figure 31 Direct access to CPU port PJ0 from J8 pin 2 is obtained by installing a shunt on jumper JP13 across pins A-B. See the green lines in the figure.
Page 32: Usart 1 Port - J6
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer USART 1 Port – J6 Connector J6 allows direct access to CPU ports PD2 and PD3 (via J6) if the USART 1 functions are not in use. These connections can be routed through the 3.3Vdc to 5Vdc level translators in similar fashion to USARTs 2 and 3 as described earlier.
Page 33 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Referring to Figure 33: Figure 33 First, assuming all other things equal, the green signal path shows how you can route J6 pin 1 signal through translator U8 in similar fashion to the previous USARTS by installing shunts on jumper JP6 across pins B-C and on jumper JP15 across pins A-B.
Page 34: Final Comments About Usart Direct Connections
Summary of direct access ports The following table summarizes the 48 CPU ports that are directly accessible on the RCAT™: PORT Access...
Page 35: Usarts, And Serial Communications Interfaces
Serious Power for the Serious Designer Table 4 USARTS, and Serial Communications Interfaces This section details the several different types of communications interfaces available on the RCAT™. The following is a list of all the different combinations you could have configured simultaneously. USART 0:...
Page 36 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Configuration 4 USART Interface Access Jumper(s) and port configs USART0 JP14(A-B), JP25(A-B), JP16(A-B), JP24(A-B) USART1 Logic JP6(A-B), JP7(A-B), JP15(A-B), JP17(A-B) JP20 Removed USART2 Logic/Full Duplex JP10(B-C), JP11(B-C), JP8(A-B), JP9(A-B)
Page 37 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Configuration 9 USART Interface Access Jumper(s) and port configs USART0 RS422/485 JP25(B-C), JP24(B-C) USART1 Ethernet JP6 Removed, JP7 Removed, JP15 Removed, JP17 Removed, JP20 Installed, PH7 = 0, PH6 = 1, PG5 = 0...
Page 38 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Configuration 14 USART Interface Access Jumper(s) and port configs USART0 RS232 JP14(B-C), JP25(A-B), JP16(B-C), JP24(A-B) USART1 RS232 JP15(B-C), JP17(B-C), JP20 Removed USART2 Logic/Half Duplex JP10(A-B), JP11(A-B), JP8(A-B), JP9(A-B) JP22 Removed...
Page 39 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Configuration 19 USART Interface Access Jumper(s) and port configs USART0 JP14(A-B), JP25(A-B), JP16(A-B), JP24(A-B) USART1 Ethernet JP6 Removed, JP7 Removed, JP15 Removed, JP17 Removed, JP20 Installed, PH7 = 0, PH6 = 1, PG5 = 0...
Page 40: Rs422/485 Interface
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Configuration 24 USART Interface Access Jumper(s) and port configs USART0 RS422/485 JP25(B-C), JP24(B-C) USART1 Ethernet JP6 Removed, JP7 Removed, JP15 Removed, JP17 Removed, JP20 Installed, PH7 = 0, PH6 = 1, PG5 = 0...
Page 41: Free Rs232 Channel
Free RS232 Channel The RCAT™ has one channel of the ICL3243E RS232 Transceiver that is not committed to any USART or other circuit on the board. It breaks out to connector J13 for use as you see fit. You can view the datasheet for the ICL3243E here.
Page 42 RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Referring to Figure 36 below, a 16 conductor ribbon cable connects nicely between J16 and the Netburner™. A Network able can then be connected to the Netburner™ and you are fully Ethernet-enabled. The Netburner™...
Page 43: Programming Ide (Interactive Development Environment)
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Development Systems Although many combinations of programming environments and hardware debugging and programming tools are available, our goal is to get you up and running on your system as fast and inexpensively as possible.
Page 44: Demonstration Software
Please note that the RCAT™ Startup solution uses files from the published release of FreeRTOS that have been adapted to run with the RCAT™ board. These files have been annotated as such and renamed with an “RCAT_” prefix to identify them.
Page 45: Rcat™ Specifications
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer RCAT™ Specifications Primary Operating Voltage: 5Vdc Standard Input Voltage: 5Vdc, (3A) Regulated Optional Input Voltage: 7.5Vdc to 35Vdc with installation of LM7805C and appropriate heatsink Filter Cap is already installed on board Onboard Voltages: 3.3Vdc (linear regulator –...
Page 46: Schematic Diagram
RCAT-1A Rev A3 Designer’s manual Serious Power for the Serious Designer Mechanical In addition to the dimensional diagram (Figure 37), the RCAT™ board is available as a SketchUp model on the Robot Circuits Website. You can download the file here. Figure 37 Schematic Diagram A complete schematic diagram of the RCAT™...