Entity: prim_esc_receiver
- File: prim_esc_receiver.sv
Diagram
Description
Copyright lowRISC contributors. Licensed under the Apache License, Version 2.0, see LICENSE for details. SPDX-License-Identifier: Apache-2.0
This module decodes escalation enable pulses that have been encoded using the prim_esc_sender module.
The module supports in-band ping testing of the escalation wires. This is accomplished by the sender module that places a single-cycle, differentially encoded pulse on esc_p/n which will be interpreted as a ping request by the receiver module. The receiver module responds by sending back the response pattern "1010".
Native escalation enable pulses are differentiated from ping requests by making sure that these pulses are always longer than 1 cycle.
See also: prim_esc_sender, prim_diff_decode, alert_handler
Generics
| Generic name | Type | Value | Description |
|---|---|---|---|
| N_ESC_SEV | int | 4 | The number of escalation severities. Should be set to the Alert Handler's N_ESC_SEV when this primitive is instantiated. |
| PING_CNT_DW | int | 16 | The width of the Alert Handler's ping counter. Should be set to the Alert Handler's PING_CNT_DW when this primitive is instantiated. |
| MarginFactor | int | 4 | This counter monitors incoming ping requests and auto-escalates if the alert handler ceases to send them regularly. The maximum number of cycles between subsequent ping requests is N_ESC_SEV x (2 x 2 x 2**PING_CNT_DW), see also implementation of the ping timer (alert_handler_ping_timer.sv). The timeout counter below uses a timeout that is 4x larger than that in order to incorporate some margin. Do NOT modify this counter value, when instantiating it in the design. It is only exposed to reduce the state space in the FPV testbench. |
| NumWaitCounts | int | 2 | |
| NumTimeoutCounts | int | 2 | |
| TimeoutCntDw | int | $clog2(Marg |
Ports
| Port name | Direction | Type | Description |
|---|---|---|---|
| clk_i | input | ||
| rst_ni | input | ||
| esc_en_o | output | escalation enable | |
| esc_rx_o | output | esc_rx_t | escalation / ping response |
| esc_tx_i | input | esc_tx_t | escalation output diff pair |
Signals
| Name | Type | Description |
|---|---|---|
| esc_level | logic | /////////////////////////////// decode differential signals // /////////////////////////////// |
| esc_p | logic | /////////////////////////////// decode differential signals // /////////////////////////////// |
| esc_n | logic | /////////////////////////////// decode differential signals // /////////////////////////////// |
| sigint_detected | logic | /////////////////////////////// decode differential signals // /////////////////////////////// |
| ping_en | logic | ////////////////////////////////////////// Ping Monitor Counter / Auto Escalation // ////////////////////////////////////////// |
| esc_en | logic | ////////////////////////////////////////// Ping Monitor Counter / Auto Escalation // ////////////////////////////////////////// |
| cnt_q | logic [1:0][TimeoutCntDw-1:0] | |
| state_d | state_e | |
| state_q | state_e | |
| resp_pd | logic | |
| resp_pq | logic | |
| resp_nd | logic | |
| resp_nq | logic | |
| resp_p | esc_tx_i |
Constants
| Name | Type | Value | Description |
|---|---|---|---|
| MarginFactor | int | 4 | This counter monitors incoming ping requests and auto-escalates if the alert handler ceases to send them regularly. The maximum number of cycles between subsequent ping requests is N_ESC_SEV x (2 x 2 x 2**PING_CNT_DW), see also implementation of the ping timer (alert_handler_ping_timer.sv). The timeout counter below uses a timeout that is 4x larger than that in order to incorporate some margin. Do NOT modify this counter value, when instantiating it in the design. It is only exposed to reduce the state space in the FPV testbench. |
| NumWaitCounts | int | 2 | |
| NumTimeoutCounts | int | 2 |
Types
| Name | Type | Description |
|---|---|---|
| state_e | enum logic [2:0] { Idle, Check, PingResp, EscResp, SigInt} |
/////////////// RX/TX Logic // /////////////// |
Processes
- p_fsm: ( )
Type: always_comb
- p_regs: ( @(posedge clk_i or negedge rst_ni) )
Type: always_ff
Description
///////////// Registers // /////////////
Instantiations
- u_prim_buf_esc: prim_buf
Description
This prevents further tool optimizations of the differential signal.
- u_decode_esc: prim_diff_decode
- u_prim_generic_flop: prim_generic_flop
Description
This prevents further tool optimizations of the differential signal.