Entity: IirSimple
- File: IirSimple.vhd
Diagram
Description
Company : SLAC National Accelerator Laboratory
Description: Simple IIR filter using bitshifts y(n) = alphax(n) + (1 - alpha)y(n-1) where alpha = 2**(-IIR_SHIFT_G) optionally supports time multiplexed channels with the
ILEAVE_CHAN_G generic
This file is part of 'SLAC Firmware Standard Library'. It is subject to the license terms in the LICENSE.txt file found in the top-level directory of this distribution and at: https://confluence.slac.stanford.edu/display/ppareg/LICENSE.html. No part of 'SLAC Firmware Standard Library', including this file, may be copied, modified, propagated, or distributed except according to
the terms contained in the LICENSE.txt file.
Generics
| Generic name | Type | Value | Description |
|---|---|---|---|
| TPD_G | time | 1 ns | |
| XIL_DEVICE_G | string | "ULTRASCALE_PLUS" | |
| USE_CSA3_G | boolean | false | |
| BRAM_THRESH_G | integer | 256 | |
| IIR_SHIFT_G | integer | 4 | alpha = 2**(-IIR_SHIFT_G) |
| ILEAVE_CHAN_G | integer | 1 | Number of interleaved channels |
| USER_WIDTH_G | integer | 0 | |
| REG_IN_G | boolean | true | |
| REG_OUT_G | boolean | true |
Ports
| Port name | Direction | Type | Description |
|---|---|---|---|
| clk | in | sl | |
| rst | in | sl | |
| validIn | in | sl | inputs |
| userIn | in | slv(USER_WIDTH_G - 1 downto 0) | |
| din | in | sfixed | |
| validOut | out | sl | outputs |
| userOut | out | slv(USER_WIDTH_G - 1 downto 0) | |
| dout | out | sfixed |
Signals
| Name | Type | Description |
|---|---|---|
| r | RegType | |
| rin | RegType | |
| dinInt | sfixed(din'range) | |
| doutInt | sfixed(dout'range) | |
| filtOut | sfixed(dout'high downto dout'low - IIR_SHIFT_G) | |
| filtDly | sfixed(dout'high downto dout'low - IIR_SHIFT_G) | |
| userDelayIn | slv(userIn'length downto 0) | add 1 bit so we can delay valid and user together |
| userDelayOut | slv(userIn'length downto 0) | |
| shiftInA | sfixed(din'high - IIR_SHIFT_G downto din'low - IIR_SHIFT_G) | |
| shiftInB | sfixed(filtOut'high - IIR_SHIFT_G downto filtOut'low - IIR_SHIFT_G) |
Constants
| Name | Type | Value | Description |
|---|---|---|---|
| IIR_DELAY_C | integer | ILEAVE_CHAN_G - 1 | |
| IIR_DELAY_STYLE_C | string | ite(IIR_DELAY_C > BRAM_THRESH_G, "block", "srl_reg") |
|
| TOT_LATENCY_C | integer | 1 + ite(REG_IN_G, 1, 0) + ite(REG_OUT_G, 1, 0) |
Latency for user/valid |
| INT_OVERFLOW_STYLE_C | fixed_overflow_style_type | fixed_wrap | |
| INT_ROUNDING_STYLE_C | fixed_round_style_type | fixed_truncate | |
| REG_INIT_C | RegType | ( din => (others => '0'), dout => (others => '0')) |
Types
| Name | Type | Description |
|---|---|---|
| RegType |
Processes
- comb: ( din, filtOut, r )
- seq: ( clk )
Instantiations
- U_USER_DELAY: surf.SlvFixedDelay
- U_ACCUM_DELAY: surf.sfixedDelay
- U_ADD_SUB: surf.add3