DESIGN OF A CUSTOM ASIC INCORPORATING CAN™ AND 1 ...

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5.3.17 CAN Module Receive Buffer Identifier Register (RBI) The layout and bit definitions for the Receive Buffer Identifier Register, shown in Figure 5.29, are identical to the TBI register (See Section 5.3.13). Figure 5.29 CAN Receive Buffer Identifier Register. 5.3.18 CAN Module Remote Transmission Request/Data Length Code Register (RRTDL) The layout of this register, shown in Figure 5.30, along with the bit names and meanings are identical to the TRTDL register as discussed in Section 5.3.14. Figure 5.30 CAN Remote Transmission Request/Data Length Code Register. 5.3.19 CAN Module Receive Data Segment Registers (RDS) 1 – 8 The layout and bit definitions of these registers, shown in Figure 5.31, are identical to the TDSx registers discussed in Section 5.3.15. Figure 5.31 CAN Receive Data Segment Registers. 165
5.3.20 CAN Node Overview As stated in Section 4.3.2, each individual CAN node is comprised of an 8-pin Microchip PIC12CE674 microcontroller [42], an 18-pin Microchip MCP2515 Stand-Alone CAN Controller [46], and an 8-pin Microchip MCP2551 High-Speed CAN transceiver [45]. Together these create a fully autonomous CAN node, which supports both “time-based” (in the sense that messages are automatically transmitted from each CAN node every 500 ms) and “event-driven” message transmission. Each individual node is interrupt driven and capable of monitoring five external inputs (two analog and three digital) and automatically generating messages based upon their value. The node also controls two digital outputs, responding to message requests via the CAN network and generating a repeating, time-based message. Each node is configured for a maximum CAN bus speed of 125 kbps, which is closest to the overdrive speed of 1 – Wire® devices, and is capable of handling standard or extended frames. Figure 5.32 shows the block diagram of one CAN node. There are two function blocks. The first is the Control Logic block. This function is performed by the PIC12CE674 microcontroller. The PIC12CE674 was chosen because of the low pin count and powerful feature set, including an internal oscillator; on-board, multi-channel, 8-bit analog-to-digital converter (ADC); multiple interrupt sources; and low-power sleep mode. The second is the CAN Interface block. This block is comprised of the MCP2515 CAN Controller and the MCP2551 transceiver. The MCP2515 provides a full CAN 2.0 implementation with message filtering, which relieves the host microcontroller from having to perform any CAN bus related overhead. This is a key feature given the limited available code space of the PIC12CE674. 166
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DESIGN OF A CUSTOM ASIC INCORPORATI
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ABSTRACT The vast majority of today
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LIST OF ABBREVIATIONS AND SYMBOLS A
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ISO International Organization for
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SI Serial In SO Serial Out SOF Star
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ACKNOWLEDGEMENTS I would like to ex
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2.4 Types of Devices...............
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4.3.5 Communication Speed Different
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5.3.21.1 Synchronization Test (test
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5.3 Resource Utilization...........
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LIST OF FIGURES 2.1 1 - Wire® Netw
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4.12 Read-Data Time Slot...........
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6.4 DS1996 Address Registers ......
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manufacturing process. Structured o
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describes the 1 - Wire® and CAN co
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2.2 1 - Wire® Overview The basis o
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All 1 - Wire® masters described in
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attachments, microcontroller with b
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Figure 2.3 Bidirectional port pin w
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2.3.3 Synthesizable 1 - Wire® Bus
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Figure 2.7 UART/RS232 Serial Port I
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hardware. Through control registers
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Table 2.2 1 - Wire® Bus Operations
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2.3.6 1 - Wire® Search Algorithm F
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detected. This ‘read two bits’
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in Figure 2.15. Alternatively, the
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of the bit, then write the desired
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2.4.2 Device Functions and Typical
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and development (R&D) investments b
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2.5 Network Types and Precedents As
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2.5.2 1 - Wire® Network Topologies
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2.5.3 1 - Wire® Network Limitation
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with a single selected slave. If an
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user group was founded in March of
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protocol on multiple media for maxi
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ecessive bit and the monitored stat
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specification: Start-Of-Frame, Arbi
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Cyclic Redundancy Check (CRC) Field
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Arbitration FieldThe Arbitration Fi
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SOF SOF Bit 28 Bit 27 Arbitration f
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Afterwards it starts transmitting s
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Figure 3.9 Structure of the Interfr
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error occurs, an Error Frame is gen
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Table 3.4 Error Flag Output Timing
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3.5.2 Error-Passive A node becomes
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where tNBT is the Nominal Bit Time
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Figure 3.12 Propagation Delay Betwe
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3.6.4 Synchronization t t t t (3.
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opposite value is inserted into the
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many systems, the bus length will b
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CHAPTER 4 THE CHALLENGES OF INTERFA
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In June 2004, Maxim Integrated Prod
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Wearable sensor technology is a new
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In traditional bus architectures, o
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Figure 4.3 Centralized arbiter with
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For the initial prototype design pr
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the ID of 31 transmits a ‘0’ (d
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Recently, a technique has been prop
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procedure, then the address claim p
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paradigms are prevalent in the desi
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systems possess a higher flexibilit
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fixed identifier and hence a fixed
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348sm Cm 47 8 smbit 11-bit hea
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est-case latency occurs when the bu
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to break the 1 - Wire® network int
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ow, is most critical for power deli
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computations have device-specific p
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Table 4.7 Example results with N 2
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4.3.5 Communication Speed Different
Page 139 and 140: anging” a port pin on a microproc
Page 141 and 142: From Figure 5.1, the block I/O pins
Page 143 and 144: 5.2.2 Command Register In addition
Page 145 and 146: specifies the selected bit value to
Page 147 and 148: with i > m. This process is repeate
Page 149 and 150: Figure 5.6 Interrupt Register. OW_
Page 151 and 152: the INTR pin will be pulled high si
Page 153 and 154: master reset occurs. Table 5.2 show
Page 155 and 156: EN_FOW: Enable Force One Wire. Sett
Page 157 and 158: READ_ROM - Used to read the 64-bit
Page 159 and 160: 5.2.8.1 Single Search ROM (single_s
Page 161 and 162: 5.2.8.3 Scratchpad Memory (scratchp
Page 163 and 164: 5.2.8.4 Command Recognition (cmd_re
Page 165 and 166: TBF - The Transmit Buffer provides
Page 167 and 168: compensate for the propagation dela
Page 169 and 170: Figure 5.15 CAN Module memory map [
Page 171 and 172: ‘0’, fast speed mode will be us
Page 173 and 174: COMP-SEL: Comparator Select. When t
Page 175 and 176: Figure 5.18 CAN Status Register. B
Page 177 and 178: that buffer is given to the CPU and
Page 179 and 180: Acceptance Mask Registers (accepted
Page 181 and 182: SJW1, SJW0: Synchronization Jump Wi
Page 183 and 184: TSEG22 - TSEG10: Time Segment Bits.
Page 185 and 186: The transmit clock (ttxclk) is used
Page 187 and 188: 5.3.13 CAN Module Transmit Buffer I
Page 189: Figure 5.28 CAN Transmit Data Segme
Page 193 and 194: Read Digital InputsRead the value o
Page 195 and 196: the clock high time is either 5 µs
Page 197 and 198: Yes Perform A/D Conversion on AN0 W
Page 199 and 200: and GP2 and GP5 as outputs. With th
Page 201 and 202: external INT pin, and then branches
Page 203 and 204: Read MCP2515 Rx Buffer for Digital
Page 205 and 206: When a valid message is received, t
Page 207 and 208: Table 5.19 Resource Utilization. Re
Page 209 and 210: For this test, only one CAN node wa
Page 211 and 212: an Error Frame to be generated. Aft
Page 213 and 214: messages, acknowledge messages, or
Page 215 and 216: 5.3.21.4 Send Basic Frame Test (sen
Page 217 and 218: going from one node to 30 nodes (se
Page 219 and 220: Table 6.1 Resource Utilization. Rev
Page 221 and 222: 6.2.1 Test Verification and Overvie
Page 223 and 224: has read access to this register. T
Page 225 and 226: system configuration used for this
Page 227 and 228: or not depends on the number of rec
Page 229 and 230: 6.4. There are two receiving CAN no
Page 231 and 232: CHAPTER 7 CONCLUSIONS AND FUTURE WO
Page 233 and 234: a communication bus reset will occu
Page 235 and 236: For the synthesizable CAN Controlle
Page 237 and 238: additional CAN nodes were added to
Page 239 and 240: Fall-Through Stack A LOW level on t
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In conclusion, the prototype system
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REFERENCES [1] IBM ASIC Products Ap
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[22] “CAN - a brief tutorial for
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[44] Microchip MCP2515 - Stand-Alon
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[67] K. Tindell and A. Burns, “Gu
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[88] “Verilog - A Language Refere
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