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

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BS (CAN Status Register (CSTAT) Bus Status bit) bit being set, the CAN Module waits for 128 occurrences of 11 recessive bits before starting normal operation. 5.3.4 CAN Module Command Register (CCOM) The Command Register, shown in Figure 5.17, is a write only register which contains the Release Receive Buffer (RRB) and Transmit Request (TR) bits. Bits RX0, RX1, and COMP- SEL are used to control the input comparator configuration, allowing it to operate correctly for single-wire (not implemented yet) and differential modes of operation [96]. A read of this register location will always return a value of $FF. This register may be written only when the RR bit in CCNTRL is clear. Figure 5.17 CAN Command Register. RX0: Receive Pin 0. When this bit is set to a ‘1’, VDD/2 will be connected to the input comparator. The RX0 pin is disconnected. When this bit is set to a ‘0’, the RX0 pin will be connected to the input comparator. VDD/2 is then disconnected. RX1: Receive Pin 1. Setting this bit to a ‘1’ will connect VDD/2 to the input comparator and disconnect the RX1 pin. Setting this bit to a ‘0’ will connect the RX1 pin to the input comparator and disconnect VDD/2. If, however, both RX0 and RX1 are set, or both are clear, then neither of the RX pins will be disconnected. 147
COMP-SEL: Comparator Select. When this bit is set to a ‘1’, RX0 and RX1 will be compared with VDD/2 during sleep mode. Setting this bit to a ‘0’ will cause RX0 to be compared with RX1 during sleep mode. SLEEP: Sleep Mode. Setting this bit to a ‘1’ will cause the CAN Module to enter sleep mode, as long as there are no interrupts pending and there is no activity on the bus. Otherwise, the CAN Module will issue a wake-up interrupt. Setting this bit to a ‘0’ will cause the CAN Module to function normally. If the SLEEP bit is cleared by the CPU, then the CAN Module will wake up, but will not issue a wake-up interrupt. If the SLEEP bit gets set during the reception or transmission of a message, the CAN Module will generate an immediate wake-up interrupt. This will have no effect on the transfer layer (i.e., no message will be lost or get corrupted). Any node that was sleeping and has been awakened by bus activity will not be able to receive any messages until its oscillator has started and it has found a valid end of frame sequence (11 recessive bits). COS: Clear Overrun Status. Setting this bit to a ‘1’ clears the read-only overrun status bit in the CSTAT (CAN Status Register) register. It may be written at the same time as the Release Receive Buffer (RRB) bit. Setting this bit to a ‘0’ causes no action to be performed. RRB: Release Receive Buffer. When set to a ‘1’, this bit releases the receive buffer attached to the CPU, allowing the buffer to be reused by the CAN Module. This may result in another message being received, which could cause another receive interrupt request (if RIE is set). This bit is cleared automatically when a message is received, i.e. 148
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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
Page 121 and 122: systems possess a higher flexibilit
Page 123 and 124: fixed identifier and hence a fixed
Page 125 and 126: 348sm Cm 47 8 smbit 11-bit hea
Page 127 and 128: est-case latency occurs when the bu
Page 129 and 130: to break the 1 - Wire® network int
Page 131 and 132: ow, is most critical for power deli
Page 133 and 134: computations have device-specific p
Page 135 and 136: Table 4.7 Example results with N 2
Page 137 and 138: 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: ‘0’, fast speed mode will be us
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 and 190: Figure 5.28 CAN Transmit Data Segme
Page 191 and 192: 5.3.20 CAN Node Overview As stated
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
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has read access to this register. T
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system configuration used for this
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or not depends on the number of rec
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6.4. There are two receiving CAN no
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CHAPTER 7 CONCLUSIONS AND FUTURE WO
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a communication bus reset will occu
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For the synthesizable CAN Controlle
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additional CAN nodes were added to
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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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