// 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), .X(buf_out) ); /* First 7 GPIOs have no buffering, so just connect with assignments */ assign mgmt_io_in_buf[6:0] = mgmt_io_in_unbuf[6:0]; assign mgmt_io_out_buf[6:0] = mgmt_io_out_unbuf[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_unbuf[34:0]; /* Now chain them all together */ //---------------------------------------- // mgmt_io_in, right-hand side //---------------------------------------- assign buf_in[0] = mgmt_io_in_unbuf[7]; assign mgmt_io_in_buf[7] = buf_out[0]; assign buf_in[1] = mgmt_io_in_unbuf[8]; assign mgmt_io_in_buf[8] = buf_out[1]; assign buf_in[2] = mgmt_io_in_unbuf[9]; assign mgmt_io_in_buf[9] = buf_out[2]; assign buf_in[3] = mgmt_io_in_unbuf[10]; assign mgmt_io_in_buf[10] = buf_out[3]; assign buf_in[4] = mgmt_io_in_unbuf[11]; assign mgmt_io_in_buf[11] = buf_out[4]; assign buf_in[5] = mgmt_io_in_unbuf[12]; assign mgmt_io_in_buf[12] = buf_out[5]; assign buf_in[6] = mgmt_io_in_unbuf[13]; assign buf_in[7] = buf_out[6]; assign mgmt_io_in_buf[13] = buf_out[7]; assign buf_in[8] = mgmt_io_in_unbuf[14]; assign buf_in[9] = buf_out[8]; assign mgmt_io_in_buf[14] = buf_out[9]; assign buf_in[10] = mgmt_io_in_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[34]; assign buf_in[88] = buf_out[87]; assign mgmt_io_in_buf[34] = buf_out[88]; assign buf_in[89] = mgmt_io_in_unbuf[35]; assign buf_in[90] = buf_out[89]; assign mgmt_io_in_buf[35] = buf_out[90]; assign buf_in[91] = mgmt_io_in_unbuf[36]; assign buf_in[92] = buf_out[91]; assign mgmt_io_in_buf[36] = buf_out[92]; assign buf_in[93] = mgmt_io_in_unbuf[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_unbuf[7]; assign mgmt_io_out_buf[7] = buf_out[95]; assign buf_in[96] = mgmt_io_out_unbuf[8]; assign mgmt_io_out_buf[8] = buf_out[96]; assign buf_in[97] = mgmt_io_out_unbuf[9]; assign mgmt_io_out_buf[9] = buf_out[97]; assign buf_in[98] = mgmt_io_out_unbuf[10]; assign mgmt_io_out_buf[10] = buf_out[98]; assign buf_in[99] = mgmt_io_out_unbuf[11]; assign mgmt_io_out_buf[11] = buf_out[99]; assign buf_in[100] = mgmt_io_out_unbuf[12]; assign mgmt_io_out_buf[12] = buf_out[100]; assign buf_in[101] = mgmt_io_out_unbuf[13]; assign buf_in[102] = buf_out[101]; assign mgmt_io_out_buf[13] = buf_out[102]; assign buf_in[103] = mgmt_io_out_unbuf[14]; assign buf_in[104] = buf_out[103]; assign mgmt_io_out_buf[14] = buf_out[104]; assign buf_in[105] = mgmt_io_out_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[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_unbuf[34]; assign buf_in[183] = buf_out[182]; assign mgmt_io_out_buf[34] = buf_out[183]; assign buf_in[184] = mgmt_io_out_unbuf[35]; assign buf_in[185] = buf_out[184]; assign mgmt_io_out_buf[35] = buf_out[185]; assign buf_in[186] = mgmt_io_out_unbuf[36]; assign buf_in[187] = buf_out[186]; assign mgmt_io_out_buf[36] = buf_out[187]; assign buf_in[188] = mgmt_io_out_unbuf[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_unbuf[35]; assign buf_in[191] = buf_out[190]; assign mgmt_io_oeb_buf[35] = buf_out[191]; assign buf_in[192] = mgmt_io_oeb_unbuf[36]; assign buf_in[193] = buf_out[192]; assign mgmt_io_oeb_buf[36] = buf_out[193]; assign buf_in[194] = mgmt_io_oeb_unbuf[37]; assign buf_in[195] = buf_out[194]; assign mgmt_io_oeb_buf[37] = buf_out[195]; endmodule