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

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5.3.11 CAN Module Output Control Register (COCNTRL) The Output Control Register (COCNTRL), shown in Figure 5.25, is used to determine the configuration of the output drivers on the CAN transmit pins. The Output Control Mode bits allow normal differential operation, bi-phase operation, or a special test mode to be selected (not fully implemented yet). The output drivers can be selected for pull up, pull down, or push- pull operation by selectively enabling or disabling P type and N type transistors in the output driver circuits via the OCTN0/1 and OCTP0/1 bits. The COCNTRL register also allows the data output to be inverted if required. Normal configuration is for complementary levels to be transmitted on the TX0 and TX1 pins (two-wire differential operation). The bus termination network should ensure that the bus reverts to its recessive state when the driver transistors are switched off [96]. Figure 5.25 CAN Output Control Register. OCM1 – OCM0: Output Control Mode Bits. The values of these two bits determine the output mode, as shown in Table 5.12. Table 5.12 Output Control Modes. OCM1 OCM0 Function 0 0 Bi-phase operation mode 0 1 Test mode (not fully implemented) 1 0 Normal mode 1 1 1 Bit stream transmitted on both TX0 and TX1 Normal mode 2 TX0 – bit sequence TX1 – bus clock (ttxclk) 159
The transmit clock (ttxclk) is used to indicate the end of the bit time and will be high during SYNC_SEG. For all the following modes of operation, a dominant bit is internally coded as a zero, a recessive as a one. The other output control bits are used to determine the actual voltage levels transmitted to the CAN bus for dominant and recessive bits. Bi-phase mode: If the CAN Module is isolated from the bus lines by a transformer then the bit stream has to be coded so that there is no resulting dc component. There is a flip-flop (Toggle) within the CAN Module that keeps the last dominant configuration; its direct output goes to TX0 and its complement to TX1. The flip-flop is toggled for each dominant bit; dominant bits are thus sent alternately on TX0 and TX1 (i.e. the first dominant bit is sent on TX0, the second on TX1, the third on TX0, and so on). During recessive bits, all output drivers are deactivated (i.e. high impedance). Normal Mode 1: In contrast to bi-phase mode, the bit representation is time invariant and not toggled. Normal Mode 2: For the TX0 pin this is the same as Normal Mode 1, however, the data stream to TX1 is replaced by the transmit clock. The rising edge of the transmit clock marks the beginning of a bit time. The clock pulse will be tSCL long [95]. Other Output Control Bits: The other six bits in this register, shown in Table 5.13, control the output driver configurations, to determine the format of the output signal for a given data value. 160
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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
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 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: TSEG22 - TSEG10: Time Segment Bits.
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
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
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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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