VHDL Source: olo_base_wconv_xn2n
This component implements a data width conversion from a multiple N-bits to a N-bits. The sample rate (Valid pulse rate) is increased accordingly. The width conversion implements AXI-S handshaking signals to handle back-pressure.
The width conversion does support back-to-back conversions (Out_Valid/In_ready can stay high all the time).
This block can also be used for Parallel to TDM conversion (see Conventions)
The entity does little-endian data alignment as shown in the figure below.
The with conversion does also handle the last-flag according to AXI specification and it can do alignment. To do so, an input word-enable signal In_WordEna exists (one bit per OutWidth_g bits). Words that are not enabled are not sent to the output. If the input is marked with the In_Last flag, the last enabled word is marked with Out_Last at the output.
Note that with the assertion of In_Last at least one byte of the data must be valid (In_WordEna high). Otherwise it would be unclear when Out_Last shall be assigned.
This entity does only do a width conversion but not clock crossing. If a double-clock-half-width conversion is required, olo_base_cc_n2xn component can be used in front of the width conversion.
| Name | Type | Default | Description |
|---|---|---|---|
| InWidth_g | positive | - | Input width in bits. Must be an integer multiple of OutWidth_g |
| OutWidth_g | positive | - | Output width in bits. |
| Name | In/Out | Length | Default | Description |
|---|---|---|---|---|
| Clk | in | 1 | - | Clock |
| Rst | in | 1 | - | Reset input (high-active, synchronous to Clk) |
| Name | In/Out | Length | Default | Description |
|---|---|---|---|---|
| In_Data | in | InWidth_g | - | Input data |
| In_WordEna | in | InWidth_g/OutWidth_g | Input word-enable. Works like byte-enable but with one bit per output-word. At least one word must be enabled together with the assertion of In_Last. | |
| In_Valid | in | 1 | all '1' | AXI4-Stream handshaking signal for In_Data |
| In_Ready | out | 1 | N/A | AXI4-Stream handshaking signal for In_Data |
| In_Last | in | 1 | '0' | AXI4-Stream end of packet signaling for In_Data |
| Name | In/Out | Length | Default | Description |
|---|---|---|---|---|
| Out_Data | out | OutWidth_g | N/A | Output data |
| Out_Valid | out | 1 | N/A | AXI4-Stream handshaking signal for Out_Data |
| Out_Ready | in | 1 | '1' | AXI4-Stream handshaking signal for Out_Data |
| Out_Last | out | 1 | N/A | AXI4-Stream end of packet signaling for Out_Data |
The architecture of the entity is simple, not detailed description is required.