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Added buffers to the top level, inside a macro called 

gpio_signal_buffering (gpio_signal_buffering_alt in caravan).
Note that this macro requires manual placement and routing, like
the padframe, and the top level will need to route around its own
internal routes.
This commit is contained in:
Tim Edwards 2022-10-13 13:29:27 -04:00
parent dc3119ca91
commit f7ec0cd012
6 changed files with 873 additions and 10 deletions
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31
verilog/rtl/caravan.v
View File

@ -209,12 +209,18 @@ module caravan (
// ser_tx = mprj_io[6] (output)
// irq = mprj_io[7] (input)
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in; /* one- and three-pin data in */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out; /* one- and three-pin data out */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in; /* two- and three-pin data in */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out; /* two- and three-pin data out */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_oeb; /* output enable, used only by */
/* three-pin interfaces */
wire [`MPRJ_PWR_PADS-1:0] pwr_ctrl_nc; /* no-connects */
/* Buffers are placed between housekeeping and gpio_control_block */
/* instances to mitigate timing issues on very long (> 1.5mm) wires. */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in_hk; /* mgmt_io_in at housekeeping */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out_hk; /* mgmt_io_out at housekeeping */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_hk; /* mgmt_io_oeb at housekeeping */
wire clock_core;
// Power-on-reset signal. The reset pad generates the sense-inverted
@ -251,6 +257,21 @@ module caravan (
wire flash_io0_do, flash_io1_do;
wire flash_io0_di, flash_io1_di;
`ifndef NO_TOP_LEVEL_BUFFERING
assign mgmt_io_in_hk = mgmt_io_in;
assign mgmt_io_out = mgmt_io_out_hk;
assign mgmt_io_oeb = mgmt_io_oeb_hk;
`else
gpio_signal_buffering_alt sigbuf (
.mgmt_io_in_unbuf(mgmt_io_in),
.mgmt_io_out_unbuf(mgmt_io_out_hk),
.mgmt_io_oeb_buf(mgmt_io_oeb_hk),
.mgmt_io_in_buf(mgmt_io_in_hk),
.mgmt_io_out_buf(mgmt_io_out),
.mgmt_io_oeb_unbuf(mgmt_io_oeb)
);
`endif
chip_io_alt #(
.ANALOG_PADS_1(`ANALOG_PADS_1),
.ANALOG_PADS_2(`ANALOG_PADS_2)
@ -775,9 +796,9 @@ module caravan (
.serial_data_1(mprj_io_loader_data_1),
.serial_data_2(mprj_io_loader_data_2),
.mgmt_gpio_in(mgmt_io_in),
.mgmt_gpio_out(mgmt_io_out),
.mgmt_gpio_oeb(mgmt_io_oeb),
.mgmt_gpio_in(mgmt_io_in_hk),
.mgmt_gpio_out(mgmt_io_out_hk),
.mgmt_gpio_oeb(mgmt_io_oeb_hk),
.pwr_ctrl_out(pwr_ctrl_nc), /* Not used in this version */

2
verilog/rtl/caravan_netlists.v
View File

@ -64,6 +64,7 @@
`include "gl/gpio_defaults_block_0403.v"
`include "gl/gpio_defaults_block_1803.v"
`include "gl/gpio_defaults_block_0801.v"
`include "gl/gpio_signal_buffering_alt.v"
`include "gl/gpio_logic_high.v"
`include "gl/xres_buf.v"
`include "gl/spare_logic_block.v"
@ -88,6 +89,7 @@
`include "constant_block.v"
`include "gpio_control_block.v"
`include "gpio_defaults_block.v"
`include "gpio_signal_buffering_alt.v"
`include "gpio_logic_high.v"
`include "xres_buf.v"
`include "spare_logic_block.v"

31
verilog/rtl/caravel.v
View File

@ -174,12 +174,18 @@ module caravel (
// ser_tx = mprj_io[6] (output)
// irq = mprj_io[7] (input)
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in; /* one- and three-pin data in */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out; /* one- and three-pin data out */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in; /* two- and three-pin data in */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out; /* two- and three-pin data out */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_oeb; /* output enable, used only by */
/* the three-pin interfaces */
wire [`MPRJ_PWR_PADS-1:0] pwr_ctrl_nc; /* no-connects */
/* Buffers are placed between housekeeping and gpio_control_block */
/* instances to mitigate timing issues on very long (> 1.5mm) wires. */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_in_hk; /* mgmt_io_in at housekeeping */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_out_hk; /* mgmt_io_out at housekeeping */
wire [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_hk; /* mgmt_io_oeb at housekeeping */
wire clock_core;
// Power-on-reset signal. The reset pad generates the sense-inverted
@ -215,6 +221,21 @@ module caravel (
wire flash_io0_do, flash_io1_do;
wire flash_io0_di, flash_io1_di;
`ifndef NO_TOP_LEVEL_BUFFERING
assign mgmt_io_in_hk = mgmt_io_in;
assign mgmt_io_out = mgmt_io_out_hk;
assign mgmt_io_oeb = mgmt_io_oeb_hk;
`else
gpio_signal_buffering sigbuf (
.mgmt_io_in_unbuf(mgmt_io_in),
.mgmt_io_out_unbuf(mgmt_io_out_hk),
.mgmt_io_oeb_buf(mgmt_io_oeb_hk),
.mgmt_io_in_buf(mgmt_io_in_hk),
.mgmt_io_out_buf(mgmt_io_out),
.mgmt_io_oeb_unbuf(mgmt_io_oeb)
);
`endif
chip_io padframe(
`ifndef TOP_ROUTING
// Package Pins
@ -714,9 +735,9 @@ module caravel (
.serial_data_1(mprj_io_loader_data_1),
.serial_data_2(mprj_io_loader_data_2),
.mgmt_gpio_in(mgmt_io_in),
.mgmt_gpio_out(mgmt_io_out),
.mgmt_gpio_oeb(mgmt_io_oeb),
.mgmt_gpio_in(mgmt_io_in_hk),
.mgmt_gpio_out(mgmt_io_out_hk),
.mgmt_gpio_oeb(mgmt_io_oeb_hk),
.pwr_ctrl_out(pwr_ctrl_nc), /* Not used in this version */

2
verilog/rtl/caravel_netlists.v
View File

@ -62,6 +62,7 @@
`include "gl/gpio_defaults_block_0403.v"
`include "gl/gpio_defaults_block_1803.v"
`include "gl/gpio_defaults_block_0801.v"
`include "gl/gpio_signal_buffering.v"
`include "gl/gpio_logic_high.v"
`include "gl/xres_buf.v"
`include "gl/spare_logic_block.v"
@ -86,6 +87,7 @@
`include "constant_block.v"
`include "gpio_control_block.v"
`include "gpio_defaults_block.v"
`include "gpio_signal_buffering.v"
`include "gpio_logic_high.v"
`include "xres_buf.v"
`include "spare_logic_block.v"

483
verilog/rtl/gpio_signal_buffering.v Normal file
View File

@ -0,0 +1,483 @@
// SPDX-FileCopyrightText: 2022 Efabless Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// SPDX-License-Identifier: Apache-2.0
/*
* gpio_signal_buffering ---
*
* This macro buffers long wires between housekeeping and the GPIO control
* blocks at the top level of caravel. The rule of thumb is to limit any
* single wire length to approximately 1.3mm. The physical (manhattan)
* distances and required buffering are as follows:
*
* Breakpoints: 1.3, 2.6, 3.9, 5.2, 6.5, 7.8 (mm)
* # buffers: 1, 2, 3, 4, 5, 6
*
* GPIO # wire length (mm) # buffers
*------------------------------------------------------
* GPIO 0 0.4 0
* GPIO 1 0.2 0
* GPIO 2 0.0 0
* GPIO 3 0.3 0
* GPIO 4 0.5 0
* GPIO 5 0.7 0
* GPIO 6 1.0 0
* GPIO 7 1.4 1
* GPIO 8 1.6 1
* GPIO 9 1.8 1
* GPIO 10 2.1 1
* GPIO 11 2.3 1
* GPIO 12 2.5 1
* GPIO 13 2.7 2
* GPIO 14 3.6 2
* GPIO 15 4.5 3
* GPIO 16 4.7 3
* GPIO 17 5.1 3
* GPIO 18 5.4 4 RHS
*-------------------------------------------------------
* GPIO 19 8.4 6 LHS
* GPIO 20 8.2 6
* GPIO 21 7.9 6
* GPIO 22 7.7 5
* GPIO 23 7.4 5
* GPIO 24 6.4 4
* GPIO 25 6.1 4
* GPIO 26 5.9 4
* GPIO 27 5.7 4
* GPIO 28 5.5 4
* GPIO 29 5.3 4
* GPIO 30 5.1 3
* GPIO 31 4.8 3
* GPIO 32 4.2 3
* GPIO 33 4.0 3
* GPIO 34 3.8 2
* GPIO 35 3.5 2
* GPIO 36 3.3 2
* GPIO 37 3.4 2
*------------------------------------------------------
* total number of buffers: 95 (x2 for input and output)
*
* OEB lines go to GPIO 0 and 1 (no buffers needed) and GPIO 35-37
* (2 buffers needed), so OEB lines need 6 additional buffers.
*
* The assumption is that all GPIOs on the left-hand side of the chip are
* routed by taking wires left from the housekeeping across the top of the
* SoC to the left side, and then up to the destination. Right-hand side
* connections go directly up the right side from the housekeeping block.
*
* Note that signal names are related to the signal being passed through;
* "in" and "out" refer to the direction of the signal relative to the
* housekeeping block in the top level. For this macro, unbuffered signals
* "unbuf" are the inputs, and buffered signals "buf" are the outputs.
*/
module gpio_signal_buffering (
`ifdef USE_POWER_PINS
vccd,
vssd,
`endif
mgmt_io_in_unbuf,
mgmt_io_out_unbuf,
mgmt_io_oeb_buf,
mgmt_io_in_buf,
mgmt_io_out_buf,
mgmt_io_oeb_unbuf
);
`ifdef USE_POWER_PINS
input vccd;
input vssd;
`endif
input [`MPRJ_IO_PADS-1:0] mgmt_io_in_unbuf;
input [`MPRJ_IO_PADS-1:0] mgmt_io_out_unbuf;
input [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_unbuf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_buf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_in_buf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_out_buf;
/* Instantiate 95 + 95 + 6 = 196 buffers of size 8 */
wire [195:0] buf_in;
wire [195:0] buf_out;
sky130_fd_sc_hd__buf_8 signal_buffers [195:0] (
`ifdef USE_POWER_PINS
.VPWR(vccd),
.VGND(vssd),
.VPB(vccd),
.VNB(vssd),
`endif
.A(buf_in),
.Y(buf_out)
);
/* First 7 GPIOs have no buffering, so just connect with assignments */
assign mgmt_io_in_buf[6:0] = mgmt_io_in[6:0];
assign mgmt_io_out_buf[6:0] = mgmt_io_out[6:0];
/* Only the last two OEB lines have buffering. All the rest are either */
/* unbuffered or else unrouted (no-connects at housekeeping) */
assign mgmt_io_oeb_buf[34:0] = mgmt_io_oeb[34:0];
/* Now chain them all together */
//----------------------------------------
// mgmt_io_in, right-hand side
//----------------------------------------
assign buf_in[0] = mgmt_io_in[7];
assign mgmt_io_in_buf[7] = buf_out[0];
assign buf_in[1] = mgmt_io_in[8];
assign mgmt_io_in_buf[8] = buf_out[1];
assign buf_in[2] = mgmt_io_in[9];
assign mgmt_io_in_buf[9] = buf_out[2];
assign buf_in[3] = mgmt_io_in[10];
assign mgmt_io_in_buf[10] = buf_out[3];
assign buf_in[4] = mgmt_io_in[11];
assign mgmt_io_in_buf[11] = buf_out[4];
assign buf_in[5] = mgmt_io_in[12];
assign mgmt_io_in_buf[12] = buf_out[5];
assign buf_in[6] = mgmt_io_in[13];
assign buf_in[7] = buf_out[6];
assign mgmt_io_in_buf[13] = buf_out[7];
assign buf_in[8] = mgmt_io_in[14];
assign buf_in[9] = buf_out[8];
assign mgmt_io_in_buf[14] = buf_out[9];
assign buf_in[10] = mgmt_io_in[15];
assign buf_in[11] = buf_out[10];
assign buf_in[12] = buf_out[11];
assign mgmt_io_in_buf[15] = buf_out[12];
assign buf_in[13] = mgmt_io_in[16];
assign buf_in[14] = buf_out[13];
assign buf_in[15] = buf_out[14];
assign mgmt_io_in_buf[16] = buf_out[15];
assign buf_in[16] = mgmt_io_in[17];
assign buf_in[17] = buf_out[16];
assign buf_in[18] = buf_out[17];
assign mgmt_io_in_buf[17] = buf_out[18];
assign buf_in[19] = mgmt_io_in[18];
assign buf_in[20] = buf_out[19];
assign buf_in[21] = buf_out[20];
assign buf_in[22] = buf_out[21];
assign mgmt_io_in_buf[18] = buf_out[22];
//----------------------------------------
// mgmt_io_in, left-hand side
//----------------------------------------
assign buf_in[23] = mgmt_io_in[19];
assign buf_in[24] = buf_out[23];
assign buf_in[25] = buf_out[24];
assign buf_in[26] = buf_out[25];
assign buf_in[27] = buf_out[26];
assign buf_in[28] = buf_out[27];
assign mgmt_io_in_buf[19] = buf_out[28];
assign buf_in[29] = mgmt_io_in[20];
assign buf_in[30] = buf_out[29];
assign buf_in[31] = buf_out[30];
assign buf_in[32] = buf_out[31];
assign buf_in[33] = buf_out[32];
assign buf_in[34] = buf_out[33];
assign mgmt_io_in_buf[20] = buf_out[34];
assign buf_in[35] = mgmt_io_in[21];
assign buf_in[36] = buf_out[35];
assign buf_in[37] = buf_out[36];
assign buf_in[38] = buf_out[37];
assign buf_in[39] = buf_out[38];
assign buf_in[40] = buf_out[39];
assign mgmt_io_in_buf[21] = buf_out[40];
assign buf_in[41] = mgmt_io_in[22];
assign buf_in[42] = buf_out[41];
assign buf_in[43] = buf_out[42];
assign buf_in[44] = buf_out[43];
assign buf_in[45] = buf_out[44];
assign mgmt_io_in_buf[22] = buf_out[45];
assign buf_in[46] = mgmt_io_in[23];
assign buf_in[47] = buf_out[46];
assign buf_in[48] = buf_out[47];
assign buf_in[49] = buf_out[48];
assign buf_in[50] = buf_out[49];
assign mgmt_io_in_buf[23] = buf_out[50];
assign buf_in[51] = mgmt_io_in[24];
assign buf_in[52] = buf_out[51];
assign buf_in[53] = buf_out[52];
assign buf_in[54] = buf_out[53];
assign mgmt_io_in_buf[24] = buf_out[54];
assign buf_in[55] = mgmt_io_in[25];
assign buf_in[56] = buf_out[55];
assign buf_in[57] = buf_out[56];
assign buf_in[58] = buf_out[57];
assign mgmt_io_in_buf[25] = buf_out[58];
assign buf_in[59] = mgmt_io_in[26];
assign buf_in[60] = buf_out[59];
assign buf_in[61] = buf_out[60];
assign buf_in[62] = buf_out[61];
assign mgmt_io_in_buf[26] = buf_out[62];
assign buf_in[63] = mgmt_io_in[27];
assign buf_in[64] = buf_out[63];
assign buf_in[65] = buf_out[64];
assign buf_in[66] = buf_out[65];
assign mgmt_io_in_buf[27] = buf_out[66];
assign buf_in[67] = mgmt_io_in[28];
assign buf_in[68] = buf_out[67];
assign buf_in[69] = buf_out[68];
assign buf_in[70] = buf_out[69];
assign mgmt_io_in_buf[28] = buf_out[70];
assign buf_in[71] = mgmt_io_in[29];
assign buf_in[72] = buf_out[71];
assign buf_in[73] = buf_out[72];
assign buf_in[74] = buf_out[73];
assign mgmt_io_in_buf[29] = buf_out[74];
assign buf_in[75] = mgmt_io_in[30];
assign buf_in[76] = buf_out[75];
assign buf_in[77] = buf_out[76];
assign mgmt_io_in_buf[30] = buf_out[77];
assign buf_in[78] = mgmt_io_in[31];
assign buf_in[79] = buf_out[78];
assign buf_in[80] = buf_out[79];
assign mgmt_io_in_buf[31] = buf_out[80];
assign buf_in[81] = mgmt_io_in[32];
assign buf_in[82] = buf_out[81];
assign buf_in[83] = buf_out[82];
assign mgmt_io_in_buf[32] = buf_out[83];
assign buf_in[84] = mgmt_io_in[33];
assign buf_in[85] = buf_out[84];
assign buf_in[86] = buf_out[85];
assign mgmt_io_in_buf[33] = buf_out[86];
assign buf_in[87] = mgmt_io_in[34];
assign buf_in[88] = buf_out[87];
assign mgmt_io_in_buf[34] = buf_out[88];
assign buf_in[89] = mgmt_io_in[35];
assign buf_in[90] = buf_out[89];
assign mgmt_io_in_buf[35] = buf_out[90];
assign buf_in[91] = mgmt_io_in[36];
assign buf_in[92] = buf_out[91];
assign mgmt_io_in_buf[36] = buf_out[92];
assign buf_in[93] = mgmt_io_in[37];
assign buf_in[94] = buf_out[93];
assign mgmt_io_in_buf[37] = buf_out[94];
//----------------------------------------
// mgmt_io_out, right-hand side
//----------------------------------------
assign buf_in[95] = mgmt_io_out[7];
assign mgmt_io_out_buf[7] = buf_out[95];
assign buf_in[96] = mgmt_io_out[8];
assign mgmt_io_out_buf[8] = buf_out[96];
assign buf_in[97] = mgmt_io_out[9];
assign mgmt_io_out_buf[9] = buf_out[97];
assign buf_in[98] = mgmt_io_out[10];
assign mgmt_io_out_buf[10] = buf_out[98];
assign buf_in[99] = mgmt_io_out[11];
assign mgmt_io_out_buf[11] = buf_out[99];
assign buf_in[100] = mgmt_io_out[12];
assign mgmt_io_out_buf[12] = buf_out[100];
assign buf_in[101] = mgmt_io_out[13];
assign buf_in[102] = buf_out[101];
assign mgmt_io_out_buf[13] = buf_out[102];
assign buf_in[103] = mgmt_io_out[14];
assign buf_in[104] = buf_out[103];
assign mgmt_io_out_buf[14] = buf_out[104];
assign buf_in[105] = mgmt_io_out[15];
assign buf_in[106] = buf_out[105];
assign buf_in[107] = buf_out[106];
assign mgmt_io_out_buf[15] = buf_out[107];
assign buf_in[108] = mgmt_io_out[16];
assign buf_in[109] = buf_out[108];
assign buf_in[110] = buf_out[109];
assign mgmt_io_out_buf[16] = buf_out[110];
assign buf_in[111] = mgmt_io_out[17];
assign buf_in[112] = buf_out[111];
assign buf_in[113] = buf_out[112];
assign mgmt_io_out_buf[17] = buf_out[113];
assign buf_in[114] = mgmt_io_out[18];
assign buf_in[115] = buf_out[114];
assign buf_in[116] = buf_out[115];
assign buf_in[117] = buf_out[116];
assign mgmt_io_out_buf[18] = buf_out[117];
//----------------------------------------
// mgmt_io_out, left-hand side
//----------------------------------------
assign buf_in[118] = mgmt_io_out[19];
assign buf_in[119] = buf_out[118];
assign buf_in[120] = buf_out[119];
assign buf_in[121] = buf_out[120];
assign buf_in[122] = buf_out[121];
assign buf_in[123] = buf_out[122];
assign mgmt_io_out_buf[19] = buf_out[123];
assign buf_in[124] = mgmt_io_out[20];
assign buf_in[125] = buf_out[124];
assign buf_in[126] = buf_out[125];
assign buf_in[127] = buf_out[126];
assign buf_in[128] = buf_out[127];
assign buf_in[129] = buf_out[128];
assign mgmt_io_out_buf[20] = buf_out[129];
assign buf_in[130] = mgmt_io_out[21];
assign buf_in[131] = buf_out[130];
assign buf_in[132] = buf_out[131];
assign buf_in[133] = buf_out[132];
assign buf_in[134] = buf_out[133];
assign buf_in[135] = buf_out[134];
assign mgmt_io_out_buf[21] = buf_out[135];
assign buf_in[136] = mgmt_io_out[22];
assign buf_in[137] = buf_out[136];
assign buf_in[138] = buf_out[137];
assign buf_in[139] = buf_out[138];
assign buf_in[140] = buf_out[139];
assign mgmt_io_out_buf[22] = buf_out[140];
assign buf_in[141] = mgmt_io_out[23];
assign buf_in[142] = buf_out[141];
assign buf_in[143] = buf_out[142];
assign buf_in[144] = buf_out[143];
assign buf_in[145] = buf_out[144];
assign mgmt_io_out_buf[23] = buf_out[145];
assign buf_in[146] = mgmt_io_out[24];
assign buf_in[147] = buf_out[146];
assign buf_in[148] = buf_out[147];
assign buf_in[149] = buf_out[148];
assign mgmt_io_out_buf[24] = buf_out[149];
assign buf_in[150] = mgmt_io_out[25];
assign buf_in[151] = buf_out[150];
assign buf_in[152] = buf_out[151];
assign buf_in[153] = buf_out[152];
assign mgmt_io_out_buf[25] = buf_out[153];
assign buf_in[154] = mgmt_io_out[26];
assign buf_in[155] = buf_out[154];
assign buf_in[156] = buf_out[155];
assign buf_in[157] = buf_out[156];
assign mgmt_io_out_buf[26] = buf_out[157];
assign buf_in[158] = mgmt_io_out[27];
assign buf_in[159] = buf_out[158];
assign buf_in[160] = buf_out[159];
assign buf_in[161] = buf_out[160];
assign mgmt_io_out_buf[27] = buf_out[161];
assign buf_in[162] = mgmt_io_out[28];
assign buf_in[163] = buf_out[162];
assign buf_in[164] = buf_out[163];
assign buf_in[165] = buf_out[164];
assign mgmt_io_out_buf[28] = buf_out[165];
assign buf_in[166] = mgmt_io_out[29];
assign buf_in[167] = buf_out[166];
assign buf_in[168] = buf_out[167];
assign buf_in[169] = buf_out[168];
assign mgmt_io_out_buf[29] = buf_out[169];
assign buf_in[170] = mgmt_io_out[30];
assign buf_in[171] = buf_out[170];
assign buf_in[172] = buf_out[171];
assign mgmt_io_out_buf[30] = buf_out[172];
assign buf_in[173] = mgmt_io_out[31];
assign buf_in[174] = buf_out[173];
assign buf_in[175] = buf_out[174];
assign mgmt_io_out_buf[31] = buf_out[175];
assign buf_in[176] = mgmt_io_out[32];
assign buf_in[177] = buf_out[176];
assign buf_in[178] = buf_out[177];
assign mgmt_io_out_buf[32] = buf_out[178];
assign buf_in[179] = mgmt_io_out[33];
assign buf_in[180] = buf_out[179];
assign buf_in[181] = buf_out[180];
assign mgmt_io_out_buf[33] = buf_out[181];
assign buf_in[182] = mgmt_io_out[34];
assign buf_in[183] = buf_out[182];
assign mgmt_io_out_buf[34] = buf_out[183];
assign buf_in[184] = mgmt_io_out[35];
assign buf_in[185] = buf_out[184];
assign mgmt_io_out_buf[35] = buf_out[185];
assign buf_in[186] = mgmt_io_out[36];
assign buf_in[187] = buf_out[186];
assign mgmt_io_out_buf[36] = buf_out[187];
assign buf_in[188] = mgmt_io_out[37];
assign buf_in[189] = buf_out[188];
assign mgmt_io_out_buf[37] = buf_out[189];
//----------------------------------------
// mgmt_io_oeb, left-hand side (only)
//----------------------------------------
assign buf_in[190] = mgmt_io_oeb[35];
assign buf_in[191] = buf_out[190];
assign mgmt_io_oeb_buf[35] = buf_out[191];
assign buf_in[192] = mgmt_io_oeb[36];
assign buf_in[193] = buf_out[192];
assign mgmt_io_oeb_buf[36] = buf_out[193];
assign buf_in[194] = mgmt_io_oeb[37];
assign buf_in[195] = buf_out[194];
assign mgmt_io_oeb_buf[37] = buf_out[195];
endmodule

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verilog/rtl/gpio_signal_buffering_alt.v Normal file
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// SPDX-FileCopyrightText: 2022 Efabless Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// SPDX-License-Identifier: Apache-2.0
/*
* gpio_signal_buffering_alt ---
*
* This macro buffers long wires between housekeeping and the GPIO control
* blocks at the top level of caravan. The rule of thumb is to limit any
* single wire length to approximately 1.3mm. The physical (manhattan)
* distances and required buffering are as follows:
*
* Breakpoints: 1.3, 2.6, 3.9, 5.2, 6.5, 7.8 (mm)
* # buffers: 1, 2, 3, 4, 5, 6
*
* GPIO # wire length (mm) # buffers
*------------------------------------------------------
* GPIO 0 0.4 0
* GPIO 1 0.2 0
* GPIO 2 0.0 0
* GPIO 3 0.3 0
* GPIO 4 0.5 0
* GPIO 5 0.7 0
* GPIO 6 1.0 0
* GPIO 7 1.4 1
* GPIO 8 1.6 1
* GPIO 9 1.8 1
* GPIO 10 2.1 1
* GPIO 11 2.3 1
* GPIO 12 2.5 1
* GPIO 13 2.7 2 RHS
*-------------------------------------------------------
* GPIO 25 6.1 4 LHS
* GPIO 26 5.9 4
* GPIO 27 5.7 4
* GPIO 28 5.5 4
* GPIO 29 5.3 4
* GPIO 30 5.1 3
* GPIO 31 4.8 3
* GPIO 32 4.2 3
* GPIO 33 4.0 3
* GPIO 34 3.8 2
* GPIO 35 3.5 2
* GPIO 36 3.3 2
* GPIO 37 3.4 2
*------------------------------------------------------
* total number of buffers: 48 (x2 for input and output)
*
* OEB lines go to GPIO 0 and 1 (no buffers needed) and GPIO 35-37
* (2 buffers needed), so OEB lines need 6 additional buffers.
*
* The assumption is that all GPIOs on the left-hand side of the chip are
* routed by taking wires left from the housekeeping across the top of the
* SoC to the left side, and then up to the destination. Right-hand side
* connections go directly up the right side from the housekeeping block.
*
* Note that signal names are related to the signal being passed through;
* "in" and "out" refer to the direction of the signal relative to the
* housekeeping block in the top level. For this macro, unbuffered signals
* "unbuf" are the inputs, and buffered signals "buf" are the outputs.
*/
module gpio_signal_buffering_alt (
`ifdef USE_POWER_PINS
vccd,
vssd,
`endif
mgmt_io_in_unbuf,
mgmt_io_out_unbuf,
mgmt_io_oeb_buf,
mgmt_io_in_buf,
mgmt_io_out_buf,
mgmt_io_oeb_unbuf
);
`ifdef USE_POWER_PINS
input vccd;
input vssd;
`endif
input [`MPRJ_IO_PADS-1:0] mgmt_io_in_unbuf;
input [`MPRJ_IO_PADS-1:0] mgmt_io_out_unbuf;
input [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_unbuf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_oeb_buf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_in_buf;
output [`MPRJ_IO_PADS-1:0] mgmt_io_out_buf;
/* Instantiate 48 + 48 + 6 = 101 buffers of size 8 */
wire [100:0] buf_in;
wire [100:0] buf_out;
sky130_fd_sc_hd__buf_8 signal_buffers [100:0] (
`ifdef USE_POWER_PINS
.VPWR(vccd),
.VGND(vssd),
.VPB(vccd),
.VNB(vssd),
`endif
.A(buf_in),
.Y(buf_out)
);
/* First 7 GPIOs have no buffering, so just connect with assignments */
assign mgmt_io_in_buf[6:0] = mgmt_io_in[6:0];
assign mgmt_io_out_buf[6:0] = mgmt_io_out[6:0];
/* Only the last two OEB lines have buffering. All the rest are either */
/* unbuffered or else unrouted (no-connects at housekeeping) */
assign mgmt_io_oeb_buf[34:0] = mgmt_io_oeb[34:0];
/* Now chain them all together */
//----------------------------------------
// mgmt_io_in, right-hand side
//----------------------------------------
assign buf_in[0] = mgmt_io_in[7];
assign mgmt_io_in_buf[7] = buf_out[0];
assign buf_in[1] = mgmt_io_in[8];
assign mgmt_io_in_buf[8] = buf_out[1];
assign buf_in[2] = mgmt_io_in[9];
assign mgmt_io_in_buf[9] = buf_out[2];
assign buf_in[3] = mgmt_io_in[10];
assign mgmt_io_in_buf[10] = buf_out[3];
assign buf_in[4] = mgmt_io_in[11];
assign mgmt_io_in_buf[11] = buf_out[4];
assign buf_in[5] = mgmt_io_in[12];
assign mgmt_io_in_buf[12] = buf_out[5];
assign buf_in[6] = mgmt_io_in[13];
assign buf_in[7] = buf_out[6];
assign mgmt_io_in_buf[13] = buf_out[7];
//----------------------------------------
// mgmt_io_in, left-hand side
//----------------------------------------
assign buf_in[8] = mgmt_io_in[25];
assign buf_in[9] = buf_out[8];
assign buf_in[10] = buf_out[9];
assign buf_in[11] = buf_out[10];
assign mgmt_io_in_buf[25] = buf_out[11];
assign buf_in[12] = mgmt_io_in[26];
assign buf_in[13] = buf_out[12];
assign buf_in[14] = buf_out[13];
assign buf_in[15] = buf_out[14];
assign mgmt_io_in_buf[26] = buf_out[15];
assign buf_in[16] = mgmt_io_in[27];
assign buf_in[17] = buf_out[16];
assign buf_in[18] = buf_out[17];
assign buf_in[19] = buf_out[18];
assign mgmt_io_in_buf[27] = buf_out[19];
assign buf_in[20] = mgmt_io_in[28];
assign buf_in[21] = buf_out[20];
assign buf_in[22] = buf_out[21];
assign buf_in[23] = buf_out[22];
assign mgmt_io_in_buf[28] = buf_out[23];
assign buf_in[24] = mgmt_io_in[29];
assign buf_in[25] = buf_out[24];
assign buf_in[26] = buf_out[25];
assign buf_in[27] = buf_out[26];
assign mgmt_io_in_buf[29] = buf_out[27];
assign buf_in[28] = mgmt_io_in[30];
assign buf_in[29] = buf_out[28];
assign buf_in[30] = buf_out[29];
assign mgmt_io_in_buf[30] = buf_out[30];
assign buf_in[31] = mgmt_io_in[31];
assign buf_in[32] = buf_out[31];
assign buf_in[33] = buf_out[32];
assign mgmt_io_in_buf[31] = buf_out[33];
assign buf_in[34] = mgmt_io_in[32];
assign buf_in[35] = buf_out[34];
assign buf_in[36] = buf_out[35];
assign mgmt_io_in_buf[32] = buf_out[36];
assign buf_in[37] = mgmt_io_in[33];
assign buf_in[38] = buf_out[37];
assign buf_in[39] = buf_out[38];
assign mgmt_io_in_buf[33] = buf_out[39];
assign buf_in[40] = mgmt_io_in[34];
assign buf_in[41] = buf_out[40];
assign mgmt_io_in_buf[34] = buf_out[41];
assign buf_in[42] = mgmt_io_in[35];
assign buf_in[43] = buf_out[42];
assign mgmt_io_in_buf[35] = buf_out[43];
assign buf_in[44] = mgmt_io_in[36];
assign buf_in[45] = buf_out[44];
assign mgmt_io_in_buf[36] = buf_out[45];
assign buf_in[46] = mgmt_io_in[37];
assign buf_in[47] = buf_out[46];
assign mgmt_io_in_buf[37] = buf_out[47];
//----------------------------------------
// mgmt_io_out, right-hand side
//----------------------------------------
assign buf_in[48] = mgmt_io_out[7];
assign mgmt_io_out_buf[7] = buf_out[48];
assign buf_in[49] = mgmt_io_out[8];
assign mgmt_io_out_buf[8] = buf_out[49];
assign buf_in[50] = mgmt_io_out[9];
assign mgmt_io_out_buf[9] = buf_out[50];
assign buf_in[51] = mgmt_io_out[10];
assign mgmt_io_out_buf[10] = buf_out[51];
assign buf_in[52] = mgmt_io_out[11];
assign mgmt_io_out_buf[11] = buf_out[52];
assign buf_in[53] = mgmt_io_out[12];
assign mgmt_io_out_buf[12] = buf_out[53];
assign buf_in[54] = mgmt_io_out[13];
assign buf_in[55] = buf_out[54];
assign mgmt_io_out_buf[13] = buf_out[55];
//----------------------------------------
// mgmt_io_out, left-hand side
//----------------------------------------
assign buf_in[56] = mgmt_io_out[25];
assign buf_in[57] = buf_out[56];
assign buf_in[58] = buf_out[57];
assign buf_in[59] = buf_out[58];
assign mgmt_io_out_buf[25] = buf_out[59];
assign buf_in[60] = mgmt_io_out[26];
assign buf_in[61] = buf_out[60];
assign buf_in[62] = buf_out[61];
assign buf_in[63] = buf_out[62];
assign mgmt_io_out_buf[26] = buf_out[63];
assign buf_in[64] = mgmt_io_out[27];
assign buf_in[65] = buf_out[64];
assign buf_in[66] = buf_out[65];
assign buf_in[67] = buf_out[66];
assign mgmt_io_out_buf[27] = buf_out[67];
assign buf_in[68] = mgmt_io_out[28];
assign buf_in[69] = buf_out[68];
assign buf_in[70] = buf_out[69];
assign buf_in[71] = buf_out[70];
assign mgmt_io_out_buf[28] = buf_out[71];
assign buf_in[72] = mgmt_io_out[29];
assign buf_in[73] = buf_out[72];
assign buf_in[74] = buf_out[73];
assign buf_in[75] = buf_out[74];
assign mgmt_io_out_buf[29] = buf_out[75];
assign buf_in[76] = mgmt_io_out[30];
assign buf_in[77] = buf_out[76];
assign buf_in[78] = buf_out[77];
assign mgmt_io_out_buf[30] = buf_out[78];
assign buf_in[79] = mgmt_io_out[31];
assign buf_in[80] = buf_out[79];
assign buf_in[81] = buf_out[80];
assign mgmt_io_out_buf[31] = buf_out[81];
assign buf_in[82] = mgmt_io_out[32];
assign buf_in[83] = buf_out[82];
assign buf_in[84] = buf_out[83];
assign mgmt_io_out_buf[32] = buf_out[84];
assign buf_in[85] = mgmt_io_out[33];
assign buf_in[86] = buf_out[85];
assign buf_in[87] = buf_out[86];
assign mgmt_io_out_buf[33] = buf_out[87];
assign buf_in[88] = mgmt_io_out[34];
assign buf_in[89] = buf_out[88];
assign mgmt_io_out_buf[34] = buf_out[89];
assign buf_in[90] = mgmt_io_out[35];
assign buf_in[91] = buf_out[90];
assign mgmt_io_out_buf[35] = buf_out[91];
assign buf_in[92] = mgmt_io_out[36];
assign buf_in[93] = buf_out[92];
assign mgmt_io_out_buf[36] = buf_out[93];
assign buf_in[94] = mgmt_io_out[37];
assign buf_in[95] = buf_out[94];
assign mgmt_io_out_buf[37] = buf_out[95];
//----------------------------------------
// mgmt_io_oeb, left-hand side (only)
//----------------------------------------
assign buf_in[96] = mgmt_io_oeb[35];
assign buf_in[97] = buf_out[96];
assign mgmt_io_oeb_buf[35] = buf_out[97];
assign buf_in[98] = mgmt_io_oeb[36];
assign buf_in[99] = buf_out[98];
assign mgmt_io_oeb_buf[36] = buf_out[99];
assign buf_in[100] = mgmt_io_oeb[37];
assign buf_in[101] = buf_out[100];
assign mgmt_io_oeb_buf[37] = buf_out[101];
endmodule