| Port Name | I/O | Clock | Description |
|---|---|---|---|
| s_axis_ctrl_tdata[15:0] | I | s_axis_aclk | Control word for the DFE FFT core. The format is described in the following table. |
| s_axis_ctrl_tvalid | I | s_axis_aclk | 'Valid' handshake signal for the control stream interface. The core uses this to indicate the upstream that a new control word is available. |
| s_axis_ctrl_tready | O | s_axis_aclk | 'Ready' handshake signal for the control stream interface. The core uses this to indicate that a control word can be accepted. |
| Control field | Width | Range | Description |
|---|---|---|---|
| Point size | 4 | 3:0 | Base-2 logarithm of point size for the corresponding data frame
(8 = 256 point, ... 12 = 4096 point). If the value is out of range, event_config_error will be signaled and the control packet will be ignored. |
| Direction | 1 | 4:4 | Transform direction for next frame to be input (0 = inverse FFT, 1 = forward FFT). |
| Maximum point size | 4 | 8:5 |
Base-2 logarithm of maximum point size for the corresponding data frame and all subsequent frames. A value of 0 is taken to mean that the maximum point size should not be changed. |
| Reserved | 7 | 15:9 | Reserved. |