What is aligned address in AXI?

What is aligned address in AXI?

If addresses are in units of bytes, byte addressable, then a byte is always aligned. Assuming a byte is 8 bits, then a 16 bit transfer would be aligned if it is on a 16 bit boundary, meaning the lower address bit is a zero.

How do you calculate wrap boundaries?

Wrap boundary or block size is determined by the Size of transfer * Beat length. Size of transfer = 2^(HSIZE) i.e = 1, for HSIZE = 0, 2 for HSIZE = 1, 4 for HSIZE = 2, 8 for HSIZE = 3….. Beat Length = 4, for WRAP4, 8 for WRAP8, and 16 for WRAP16. So why would someone want issue WRAP Burst.

What is burst length in AXI?

Burst length is number of data transfers for the burst like if ur burst length is 4 then the burst is 4 number of sequential data. now the burst size is like width of that each data, As per the AXI4 spec the burst size should be min of 8bits (1byte) that can be called as beat.

What is burst-based transaction?

From Wikipedia, the free encyclopedia. Burst mode is a generic electronics term referring to any situation in which a device is transmitting data repeatedly without going through all the steps required to transmit each piece of data in a separate transaction.

What is aligned and unaligned address?

The alignment of the access refers to the address being a multiple of the transfer size. For example, an aligned 32 bit access will have the bottom 4 bits of the address as 0x0, 0x4, 0x8 and 0xC assuming the memory is byte addressed. An unaligned address is then an address that isn’t a multiple of the transfer size.

How do you calculate wraps?

To calculate a wrap rate, divide the fully loaded rate by your base hourly labor rate. Typically, a competitive wrap rate will be somewhere between “1” and “2.”

What is wrapping AXI?

AHB AXI WRAP Burst A WRAP burst is similar to INCR burst. In WRAP the address will be incremented based the SiZE, but on reaching the upper address limit address will wrap to lower address.

What is the difference between burst and beat?

A ‘beat’ is an individual data transfer within an AXI burst. An AXI ‘burst’ is a transaction in which multiple data items are transferred based upon a single address, and it is each data item transferred that is referred to as a ‘beat’.

What is burst length?

Burst length is the amount of data transferred between the CPU and memory in each transmission.

What is unaligned address?

An unaligned address is then an address that isn’t a multiple of the transfer size. The meaning in AXI4 would be the same.

How to calculate the address of an INCR burst?

This equation determines the address of the first transfer in a burst: Address_1 = Start_Address. For an INCR burst, and for a WRAP burst for which the address has not wrapped, this equation determines the address of any transfer after the first transfer in a burst: Address_N = Aligned_Address + (N – 1) × Number_Bytes

Why is the start address determined by the AXI slave?

Because this allows you to have a start address that is part way through a WORD (where word size is set by AWSIZE) and the AXI slave (MIG) has to calculate the start address (word) based on the AxADDR (byte). 12-12-2017 05:21 AM This does not give any information on the fact the AxADDR should be a multiple of bytes…

Why is 29bit address width not 32bit in axi?

The AXI spec says these are always byte addressable, but the mig documentation (and this post: https://forums.xilinx.com/t5/Memory-Interfaces/axi-address-width-why-is-29bit-not-32bit/td-p/812508) seems to imply it may not be. doesnt this break the spec (ironic as Im asking if it also breaks the spec with the 4k boundaries)

Is the addr in axaddr a byte address?

Ok, If the addr is not a byte address, lets assume that we was to write to addr = AxAddr = 1 (as addr = start_addr = AxAddr) So all this indicates AxADDR must be a byte address. 12-12-2017 06:56 AM