Appendix A Comparison with the AXI4 Write Data Channel Read this for a description of the key differences between the AXI4-Stream interface and the AXI4 write data channel. here is the part axi slave rtl generated by vivado. Course interleaving is enabled with the memory controller mapping to multiple address regions. AXI4 does NOT support write interlacing. Of course it can have a larger addressing space, but again it has to be in the multiples of 4KB. Write interleaving; this feature was retracted by AXI4 protocol. AXI_DATA_WIDTH = 512, this is unchangeable in the MIG UI, but seems perfect for us, as we write 512 bit words. sequence_length This site uses cookies to store information on your computer. The AMBA AXI-4 system consists. One major up-dation seen in AXI is that, it includes information on the use of default signaling andSupports multiple outstanding transactions: * Supports connected masters with multiple reordering depth (ID threads). With reorder depth / interleaving depth of 1, everything has to be in-order regardless of IDs. Read Data Interleaving is supported in AXI4 and following is my understanding on Data Interleaving: Multiple Read commands can be executed simultaneously and data interleaving is supported as long as all condition for ordering are followed. The AMBA AXI4 Interconnect core connects one or more AXI memory-mapped master devices to one or more memory-mapped slave devices. Then when reading back, each successive pixel comes from a new bank allowing some interleaving of row activation and readout. Write standard new() function. I'm research info AMBA 3. AXI uses well defined master and slave interfaces that communicate via five different channels: Read address; Read data; Write address; Write data; Write response; Figure 1 shows the five AXI channels. By continuing to use our site, you consent to our cookies. 1) A1 A2 B1 B2 (In-order)-> This is legal. Chip Select Interleaving controls how these four chip selects are interleaved within the memory controller. The primary reason for removing WID was NOT to reduce the interface pin count, it was imply that the WID signal was no longer needed. The AXI protocol provides the dedicated channels for memory read and write operations. 2、什么是interleaving交织机制. 2. There is one write strobe for each eight bits of the write data bus. 1. For each of the AXI channels the flow of information is one direction, so for the AW, AR and W channels the flow is master to slave, and for R and B the flow is slave to master. The slave DMA usage consists of following steps: Allocate a DMA slave channel. uitable for. apb_test doesn't extend from uvm_test. but i have two getting about AXI next hi. Write Data Interleaving in AXI. Synopsys supporting burst lengths up to 256 beats inbound AXI3 I have also seen many PROTECTION vendors. wdata { Write data, actual data to be written. Provides the blended video/audio to the PL via native video output or streaming AXI. Scenario 1: There is Only 1 AXI master (with support of only 1 Master ID) doing transaction to a slave which is capable of handling multiple outstanding addresses. If you are not happy with the use of these cookies, please review our Cookie Policy to learn how they can be disabled. Because the AXI protocol allows simultaneous read and write commands to be issued, two SDRAM control ports are required to form an AXI interface. Performance constraint on the minimum expected bandwidth for write transfers in a given time interval. Recently, I read "AMBA AXI Protocol. The out-of-order means a relationship between address PupilPath Login and data. This is to simplify the address decoding in the interconnect. By continuing to use our site, you consent to our cookies. Develop and analyze applications with graphics and gaming tools, guides, and training for games developers. You say just an out-of-order responses by the interleaving. 3. v : AXI nonblocking crossbar interconnect rtl/axi. • Support for Read-only and Write-only masters and slaves, resulting in reduced resource utilization. LogiCORE IP AXI Interconnect v2. Short burst of or alternating read/write data. AXI-Pack achieves near-ideal peak on-chip bus utilizations of 87% and 39%, speedups of 5. Appendix A Comparison with the AXI4 Write Data Channel Read this for a description of the key differences between the AXI4-Stream interface and the AXI4 write data channel. 4 Standards Compliance The DW_axi_gs conforms to the AMBA 3 AXI and AMBA 4 AXI specifications defined in the AMBA AXI and ACE Protocol Specification from ARM. The DMAC does not generate interleaved write data. A master interface's write interleaving capability is the number of active transactions for. . Without extensions, linear, fixed, and. AXI specs in fact talks only about point to point communication, ie. >In AXI4 multi-master case how/where can i control 2 masters which are trying to access a single slave? First of all, an AXI4 master must not issue interleaved write data. You can also instantiate the AXI Data Width Converter core directly in your design (without AXI Interconnect core) along any pathway between a wide AXI master device and a narrower AXI slave. 2. Is AXI write data interleaving used when we have multi-master cases?-> Yes. Arbiter avoids the collision, when two masters initiate the transaction at a same time. Enables sharing the PCIe AXI DMA module between multiple request sources, interleaving requests and distributing responses. This document gives explanation about Cortex-A9 AXI masters. Thank you for your feedback. I'm interested to know what happens if on an AXI write transaction, the WR data channel put the channel info before the address channel info is valid. The problem I am facing is in AXI interface of MIG where 4-bit ID signal is present for all the transactiChip Select Interleaving For devices that have a single memory controller, Chip Select Interleaving is the only type of interleaving available. D14Supports AXI Master, AXI Slave, AXI Interconnect; Supports all ARM AMBA AXI 3. The pcie_us_axis_cq_demux module can be. AXI Slave 0 IF AXI Slave 15 IF AXI Master0 IF AXI Master1 IF AXI Master2 IF AXI Master3 IF AXI Slave 16 IF:: Figure 1 CoreAXI Block Diagram. For this the highest bits of the aw_id get pushed into a FIFO. b). Your write addresses are 1,2,3. interleaving. When 256 bits data is chosen in the GUI, this bus should be left undriven. Your write addresses are 1,2,3. AMBA. 4. By disabling cookies, some features of the site will not workI'm a graduate student living in south Korea. Data Interleaving: In a multi master interconnect, lets consider master A initiated the transfer with a burst of 4 and master B with a burst of 2 then it follows as A1 B1 A2 B2 A3 A4 it means A started the transaction, then went to B because of idle cycle by A and again A likewise. Issues B and C of this document included an AXI specification version, v1. emory. It is a widely implemented Practice in the Computational field. Programmable interleave size per transaction to allow fixed and variable data interleaving in a transaction. Introduction. Of course it can have a larger addressing space, but again it has to be in the multiples of 4KB. Typical Use Case for AXI DMA and AXI4 Ethernet. The AXI master writes to memory locations @0x2000000 to 0x3fffffff. QoS, Write Data Interleaving, unaligned data transfer, byte invariance. AXI4 supports QoS, AXI3 does NOT support QoS. 4. Chapter 2 Signal Descriptions Refer to this chapter for definitions of the AXI global, write address channel, write data channel, write response channel, read address channel, read data channel, and low-power interface signals. "For a slave that supports write data interleaving, the order that it receives the first data item of each However, a master interface can interleave write data with different WID values if the slave interface has a write data interleaving depth greater than one. Write-Write-Write-Write or Write-Read-Write-Read, etc. All five transaction channels use the same VALID/READY handshake processInterleaving allows you to send WID transfers for a number of outstanding AW transfers, BUT. 1. 5. 0 AXI. i want to do random write transcation, and here is the waveform, does this waveform meets AXI spec. AXI is arguably the most popular of all AMBA interface interconnect. 1 Answer. And as section A5. AXI3 supports write interleaving. The core handles maximum of four (based on WR_ACCEPTANCE parameter) outstanding write addresses. g. 0 AXI. 4. Allows for parallel read and write transactions. . Chapter 4 Transfer Interleaving and Ordering Read this for a description of the stream interleaving and ordering restrictions. You will see that wvalid is indeed changing while tready is low which is against the AXI specification. The slave declares a write data interleaving depth that indicates if the interface can accept interleaved write data from sources with different AWID values. SIMON FRASER UNIVERSITY. Digital designers will learn about the differences between common bus-based and recent transaction based interconnection architectures. 是否支持读交织只与slave的设计有关。. 2. No. I'm studying about AMBA 3. The base addresses for slaves in the interconnect are also hence assigned in multiples of 4K. These features enable the implementation of high-performance interconnect, maximising data throughput and system efficiency. Where interleaving is supported, the WID and RID signals will indicate which of the interleaved transactions the data transfer relates to. * Multi-threaded traffic (masters issuing multiple ID threads) is supported across the interconnect topology regardless of internal. Since the scoreboard is a uvm_component. transfer. DataMover AXI4 Write. D11 D21 D22 D12 D23 D31 D13. Also s_axi_awqos, s_axi_arqos, m_axi_awqos, m_axi_arqos are present, which should not be the case for AXI3, as. 1) IP核。 设置Memory Depth 为262144。 BRAM Instance 选择. AXI3 master devices must be configured as if connected to a slave with a Write interleaving depth of one. 标准化：配套提供标准模型和检查器以供设计人员使用。. FIG. the data interleaving is responsible for slaves and the write data interleaving is responsible for masters. The AMBA AXI4 Interconnect core connects one or more AXI memory-mapped master devices to one or more memory-mapped slave devices. A locked transaction is changed to a non-locked transaction and propagated by the MI. As shown in FIG. >In case if we have 2 burst transfers with A (awid=0,wlen=2), B (awid=1,wlen=2) then this can be interleaved as following Let's assume that A is issued first. By disabling cookies, some features of the site will. Signals in this interface contains only minimum set of signals that are required to perform single write operation on AXI bus with fixed size and burst type. If the transaction is indicated as "non-modifiable," and both the Read and Write commands use the same ARID/AWID, the order must be preserved. Bytes) AXI Interconnect Product Guide v2. QoS signals are propagated from SI to MI. Still, if multiple transactions are issued to Slave input of AXI interconnect, it is not accepting. The order within a single burst is maintained The order of first data needs to be the same with that of request Write Interleave Cability The maximum number of transactions that master can interleave ADDRESS A11 A21 A31. [1] [2] AXI has been introduced in 2003 with the AMBA3 specification. signaling. I have seen many IP providers e. This is to simplify the address decoding in the interconnect. Why do we need AXI protocol? The AXI is a point to point interconnect that designed for high performance, high speed microcontroller systems. mem_rdata_i: input mem_data_t [NumBanks-1:0] Memory stream. 1>读乱序的例子展示的是transaction粒度的乱序，读交织进一步允许transfer粒度的乱序。. The last piece of the burst 8 transaction (RLAST) is asserted in. svt_axi_system_transaction:: slave_port_id [$] port_id of the slave transaction (s) corresponding to the master transaction. amba 3. Supports all burst types. Serial AXI Links in Broadcom System-on-Chip. One major up-dation seen in AXI is that, it includes information on the use of default signaling and Supports multiple outstanding transactions: * Supports connected masters with multiple reordering depth (ID threads). If a slave does not support write data interleaving (see Write data interleaving on page 8-6), the master must issue the data of write transactions in the same order in which it issues the transaction addresses. 3. While AXI4 props burst lengths of up the 256 beats. 1A is a view illustrating a process of interleaving the data transmitted by plural AXI masters and transmitting the interleaved data to an AXI slave 30 having interleaving acceptance capability of “2”. WID is removed in AXI4, so WDATA must strictly follow the AW order. There are a lot more interpretations of a BFM, BFMs typically reduce the job of a testbench by making it more data focused. between master and slave using a write data channel to the slave or a read data channel to the master. AMBA Specification Advanced eXtensible Interface Bus (AXI) James Chang 2011/8/1. Select the IP Configuration page. Faculty of Applied Science. v : AXI CDMA descriptor mux rtl/axi_crossbar. a 32 bit wide axi would need to turn that 0x48E word write into two axi transfers one with two byte lanes enabled in the byte mask and the second transfer with the other two byte lanes enabled. By continuing to use our site, you consent to our cookies. 3. By continuing to use our site, you consent to our cookies. AXI4 接口的主要优势. compatibility of interface parameters such as write interleaving and acceptance depths, bus widths, ID widths etc. By default this is empty, indicating that no slave transaction has been associated yet. >In AXI4 multi-master case how/where can i control 2 masters which are trying to access a single slave? First of all, an AXI4 master must not issue interleaved write data. Your write addresses are 1,2,3. Help me to understand the reasoning behind the following ordering rule imposed by AXI protocol for write data interleaving. The data widths supported are: 32, 64, 128, 256, 512 and 1024. * Supports write response reordering, Read data reordering, and Read Data interleaving. Resources Developer Site; Xilinx Wiki; Xilinx GithubThis book is for AMBA AXI Protocol Specification. 3. axi_rw_split: Splits a single read / write slave into one read and one write master. sv","contentType":"file"},{"name":"axi. 0 03 June 2011 D-2c Non-Confidential Public beta draft of AMBA AXI and ACE Protocol Specification 28 October 2011 D Non-Confidential First release of AMBA AXI and ACE Protocol SpecificationLogiCORE IP AXI Interconnect v20 Product Guide for Vivado Design Suite PG059 March 20 2013 AXI Interconnect Product Guide v20 2 PG059 March 20 2013 Table of Contents…Interleaving reading and writing In general, a program performs both input and output and these are interleaved. Write Address Read Address Write Data Read Data Write Response Channel Channel Channel Channel Channel AWID ARID WID RID BID. Support for Read-only and Write-only master devices, resulting in reduced resource utilization. 12. Word count register – It contains the. The AxiMaster and AxiLiteMaster classes implement AXI masters and are capable of generating read and write operations against AXI slaves. • Write data interleaving and write data Out-of-Order • Transaction with same ARID value to different slaves • Low-power interface of the AXI busAMBA3. See section A5. If you are not happy with the use of these cookies, please review our Cookie Policy to learn how they can be disabled. Besides Cortex-A9 master there are the other masters (DMAC, PL AXI masters) and there are AXI interconnects, that are at the same time slaves and masters, and passes write data from multiple sources (slave. The address widths can go upto 64-bits. Out of order completion. the AXI3 spec described the following (seen in all AXI spec releases up to and including version F). AXI3 supports write interleaving. By working with the master and slave devices, the AXI protocol works across five addresses that include read and write address, read and. Separate read, write and snoop channelsInterleaving simply means breaking a single transmission unit up into smaller pieces, and spreading those pieces out in time by sequencing them with pieces from other transmission units. By disabling cookies, some features of the site will not workAXI Architecture for Write • A write data channel to transfer data from the master to the slave. For example if you would like to test read operation then you also have to add all signals. 2. 接口去耦化：互连电路与. Related. This book is for AMBA AXI Protocol Specification. By continuing to use our site, you consent to our cookies. It’s demanding work that helps make “long-term memory solid, problem solving easier, and mastery improve,” notes education consultant Margaret Searle. While AXI4 supports burst lengths of up to 256 beats. I think data interleaving should not be done within a single burst. If you are not happy with the use of these cookies, please review our Cookie Policy to learn how they can be disabled. What is APB strobe? APB bridge. CPUはコンピュータの動作に必要なデータや命令を 主記憶装置 とやり取りしながら処理します。. • uses burst-based transactions with only the start address issued. of-order transaction completion, write and read data interleaving, separate read and write data channels, burst-based transactions with only start address issued and support for unaligned data transfers using byte strobes. 2. Write data interleaving 10. e. AXI Write Address. By continuing to use our site, you consent to our cookies. The write data interleaving depth is the number of different addresses that are currently pending in the slave interface for which write data can be supplied. Write Interleaving Interleaving rule Data with different ID can be interleaved. In case if we have 2 burst transfers with A (awid=0,wlen=2), B(awid=1,wlen=2) at axi slave model, then the data can be sent as following. 0 AXI. If two or four instances of the MC are selected, they are configured to form a single interleaved memory. The Arm® AMBA® 5 AXI protocol specification supports high-performance, high-frequency system designs for communication between manager and subordinate components. AXI nonblocking crossbar interconnect with parametrizable data and address interface widths and master and slave interface counts. "AXI3 supports write interleaving. We would like to show you a description here but the site won’t allow us. 0 interconnect. The write interleaving means a master will issue write data separately for one transaction. September 1, 2014 at 6:53 PM AXI GP master and write data interleaving I'm designing AXI slave to connect it to Zynq AXI GP master and I'd like to know if AXI GP master can interleave write data. AXI3 master . Spring. The AXI4 master read channel can receive transactions in any order, and data can be completely interleaved. Hi, I am trying to use DDR4 SDRAM ( MIG 2. In practice, removing write interleaving from this part of the AMBA standard makes certain aspects of the AXI protocol easier to handle. AXI has the ability to issue multiple outstanding addresses and out-oforder transaction completion, but AXI has the ability of removal of locked transactions and write interleaving. AXI has the ability to issue multiple outstanding addresses and out-oforder transaction completion, but AXI has the ability of removal of locked transactions and write interleaving. pdf". Re-ordering implies the transactions complete in a different order to that the AR channel transfers were completed, whereas interleaving suggests that more that one read data stream can be active, so data in successive transfers could be for different transactions. As per the standards, 4KB is the minm. Synopsys supporting burst lengths up to 256 beats at AXI3. PCIe AXI master module. The write data interleaving depth is the number of addresses for which a slave can accept interleaved data. >In AXI4 multi-master case how/where can i control 2 masters which are trying to access a single slave? First of all, an AXI4 master must not issue interleaved write data. 3. CoreAXI4Interconnect is a configurable core with the following features: • Supports high-bandwidth and low-latency designs. you told me that the interleaving is a concept only for write. >or its possible with single-master cases also? Yes. pcie_axi_dma_desc_mux module . sv","contentType":"file"},{"name":"axi. address does not fall to correct interleaved port. Hence you may see AXI4 Slaves and even Masters for that matter without the WID signal. The details of these operations are: Allocate a DMA slave channel. I was going through write data interleaving section in ARM AXI3 protocol. Found this statement: "For a slave that supports write data interleaving, the order in which it receives the first data item of each transaction must be the same as the order in which it receives the addresses for the transactions. The AXI port uses an AXI-3 interface. 0 data and address widths; Supports all protocol transfer types, burst types, burst lengths and response types; Supports constrained randomization of protocol attributes. In this case, the arbiter seems like compulsory for all the readback data coming from different slave & the arbiter to determine which readback data that has higher priority can or through round-robin way to return to the master. But at the same time your write strobes are 0xFFFF thus all 16 byte lines are active. メモリインターリーブ（英：memory interleaving）とは、 主記憶装置（メインメモリ）へのアクセスを高速化 する手法のひとつです。. Next Section. Match case. If you are not happy with the use of these cookies, please review our Cookie Policy to learn how they can be disabled. I'm learn about AMBA 3. when the WID is present in the old AXI version, a WDATA re-order mechanism will be inferred, and thanks to the remove of WID, we do not need that mechanism any longer. ° Write interleaving: This feature was retracted by AXI4 protocol. A master places an address on the AWADDR line and asserts a valid signal. Read issuing capability 32 Maximum of 32 only possible when translating two length 16 fixed. ° Write interleaving. Write interleaving is hardly used by regular masters but can be used by fabrics that. I'm using the Zynq 7020 (Microzed board) and have written short AXI3 master in VHDL. Secondly, the interconnect must ensure that. A. AXI Bus. sv","path":"src/axi_atop_filter. close to full bandwidth in the interleaved output stream, and maybe also in one of the input-streams, assuming the rest are slow), then we need to FIFO-buffer data corresponding to at least the size of one arbitration-block on each of the switch. #- Program AXI3 Master VIP to drive a sequence of write transactions with write data interleaving. The AXI protocol provides the dedicated channels for memory read and write operations. This is done by implementing only channels required by a specific device. It is allowed that the master can send multiple overlapping read requests to the same slave. This specification defines the AMBA AXI-Stream protocols: • AXI4-Stream • AXI5-Stream The collective term AXI-Stream is used in instances that describes common features. but i have two questions about AXI afterPrefix A Denotes global Advanced eXtensible Interface (AXI) signals: Prefix AR Denotes AXI read address channel signals. In this case, instead of waiting for one sequence to complete before the other sequence start, the AXI infrastructure can interleave the write. v. Allows reads to bypass writes, in contrast to axi_to_mem, however needs more hardware. Abstract. AHB supports the locked transfer. It is part of the Advanced Microcontroller Bus Architecture 3 (AXI3) and 4 (AXI4) specifications. 17. AXI interconnect performs Clock crossing and Data width conversion and connects to DDR4 MIG on the Master Side. AXI3 masterFigure 3 shows a timing diagram of an AXI write transaction. Provides a configurable size of user-space on each. 文章浏览阅读2. 17. With interleaving, students learn by tackling a mix of related concepts, forcing the brain to work hard to recall prior learning and determine which strategies or skills to use to solve them. . Hi, I'm a graduate student living in south Korea. 0 AXI. However most applications tended to buffer up the write data at the master and then pass it in consecutive transfer cycles, rather than try to interleave. Features of AXI 5 Channels (Write address, Write data, Write Response, Read data/response, Read address ) No strict timing relationship between address and data signal On chip, Point to Point Communication protocol Multiple Outstanding(Multiple request) Burst based transactions with only start address issued Aligned and non-aligned address support Out of order Data interleaving Atomicity. Stage 2: Write Calibration Part One 1. 1. Write interleaving is hardly used by regular masters but can be used by fabrics that. the data interleaving is responsible for slaves and the write data interleaving is responsible for masters. I have seen many IP providers e. . C_S_AXI_WRITE_ACCEPTANCE (I,U) {M}0x00000001 {M} Bit32 (0x1 - 0x20) Number of data-active Write transactions that. g. p. Write buffer between stage 1 and 2 to store interleaving write packets Parameters of AXI4[-Stream] protocol can be adjusted in AXI4. Axi handshake. svt_axi_checker: AMBA: port_interleaving: port_interleaving_check: Monitor checks that if interleaved port is expected port for the given transaction: address does fall to correct interleaved port. Recently, I read "AMBA AXI Protocol. For example, we can access all four modules concurrently, obtaining parallelism. The problem I am facing is in AXI interface of MIG where 4-bit ID signal is present for all the transactiThis site uses cookies to store information on your computer. This site uses cookies to store information on your computer. Chapter 4 Transfer Interleaving and Ordering Read this for a description of the stream interleaving and ordering restrictions. >Is it used only when we have multi-master cases? No. However, a master interface can interleave write data with different WID values if the slave interface has a write data interleaving depth greater than one. Prefix AW Denotes AXI write address channel signals. 0 AXI Spec. Include the AXI Performance Monitor IPs which will display read/write latency and bandwidth. Besides Cortex-A9 master there are the other masters (DMAC, PL AXI masters) and there are AXI interconnects, that are at the same time slaves and masters, and passes write data from multiple sources (slave interfaces), and might interleve them. The write operation process starts when the master sends an address and control information on the write address channel as shown in fig. Memory Interleaving is less or More an Abstraction technique. Please answer. Figure 2-19: AXI Reference Guide UG761 (v13. Axi handshake. Synopsys NO supporting write interlock in AXI3. 5. By continuing to use our site, you consent to our cookies. 1 in the current AXI protocol spec for details of this. I'm studying nearly AMBA 3. 1) I would like to know how read and write address requests issued to slave are associated with read or write data. AXI4 does NOT support write interleaving 3. Double-click the AXI GPIO IP block to customize it. AXI Interconnect Product Guide v2. Transaction ID信号，使AXI4协议可以完成自身的乱序机制，从AXI3到AXI4的进化中，write interleaving被取消了，大的方向下，AXI遵循着相同ID顺序执行，不同ID乱序执行的原则，同时从主设备-互联网络-从设备的连接中，Transaction ID可能会出现额外的位扩展. devices must be configured as if connected to a slave with a Write interleaving depth of one. 4. 0 Controller with AXI version for ASIC and FPGA implementations with support for the AMBA AXI protocol specification for CXL. Parameters axi_req_t: type. However, a master interface can interleave write data with different WID values if the slave interface has a write data interleaving depth greater than one. By disabling cookies, some features of the site will not workThis site uses cookies to store information on your computer. Customize the PS to enable the AXI HP0 and AXI HP2 interface: Right-click the ZYNQ7 Processing System core and select Customize Block. You may reply publicly to this message via plain. here is the part axi slave rtl generated by vivado. AXI3 master devices must be configured as if connected to a slave with a Write interleaving depth of one. 14. 首页. This site uses cookies to store information on your computer. sv","path":"src/axi_atop_filter. Write strobes. The memory controller can be programmed to enable up to four chip selects. Various busses work various ways. , Simon Fraser University, 2010. Read now: data analyst course in hyderabad. The controller provides the Read Data back to the user interface after issuing the READ command to the HBM2 DRAM. AXI Port. out of order* 4. AXI3 master In the last article, we introduced AXI, the Advanced Extensible Interface, part of the ARM AMBA specification for SoC design. This site uses cookies to store information on your computer. AXI4 supports QoS, AXI3 does NOT support QoS. In AXI Interconnect IP configuration, I changed the Acceptance parameter to 5 from 1 (All sides : Master Read/Write, Slave Read/Write). For a write transaction the W beats belonging to an AW request have to be sent in order. import all of my_pkg into your testbench. 3. NoC interleaving can be enabled or disabled. 2. For Design specification and Verification plan, refer to Memory Model. It includes the following features: ID width can range upto 32-bits. The DMA controller registers have three registers as follows. value on the address channel. atomic access, narrow transfer.