4.2.2. Arbiter signal interface

Figure 4.7 shows the signal interface of the arbiter.

Figure 4.7. Signal interface

Table 4.2 describes the signals used in the arbiter.

Table 4.2. Signal descriptions for arbiter

Signal

Direction

Description

HCLK

Input

Bus clock.

HRESETn

Input

Bus reset.

HREADY

Input

Transfer done. When HIGH, indicates that the current transfer on the bus is complete.

HRESP[1:0]

Input

The transfer response provides additional information on the status of a transfer. Four different responses are available, OKAY, ERROR, RETRY, and SPLIT.

HSPLIT[3:0]

Input

The split bus is used by a slave to indicate to the arbiter which bus masters are allowed to reattempt a split transaction. Each bit of this split bus corresponds to a single bus master.

HBURST[2:0]

Input

Indicates if the transfer forms part of a burst. Four, eight, and sixteen beat bursts are supported. The burst can be either incrementing or wrapping.

HTRANS[1:0]

Input

Indicates the type of the current transfer, which can be NONSEQUENTIAL, SEQUENTIAL, IDLE, or BUSY.

HBUSREQx

Input

Request from bus master x to the arbiter which indicates that the bus master requires the bus masters.

HLOCKx

Input

When HIGH, this signal indicates that a master requires locked access to the bus and no other master must be granted the bus until this signal is LOW.

HGRANTx

Output

This signal indicates that bus master x is currently the highest priority master. Ownership of the address/control signals changes at the end of a transfer when HREADY is HIGH, so a master gets access to the bus when both HREADY and HGRANTx are HIGH.

HMASTER[3:0]

Output

These signals from the arbiter indicate which bus master is currently performing a transfer and is used by slaves which support split transfers to determine which master is attempting an access. The timing of HMASTER is aligned with the timing of the address and control signals.

HMASTLOCK

Output

Indicates that the current master is performing a locked sequence of transfers. This signal has the same timing as the HMASTER signals.

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