module demo_packet_generator(
Reset_n,
Clk,
//--- Wishbone interface
STB_I,
CYC_I,
ADR_I,
WE_I,
DAT_I,
DAT_O,
ACK_O,
//--- Packet Descriptor Memory interface
// RdData_i is always valid exactly one clock after Addr_o changes
// and Rd_o is asserted
Rd_o,
Addr_o,
RdData_i,
//--- User (packet) interface
Rx_mac_ra,
Rx_mac_rd,
Rx_mac_data,
Rx_mac_BE,
Rx_mac_pa,
Rx_mac_sop,
Rx_mac_err,
Rx_mac_eop,
Tx_mac_wa,
Tx_mac_wr,
Tx_mac_data,
Tx_mac_BE,
Tx_mac_sop,
Tx_mac_eop
);
input Reset_n;
input Clk;
//--- Wishbone interface
input STB_I;
input CYC_I;
input [1:0] ADR_I;
input WE_I;
input [15:0] DAT_I;
output [15:0] DAT_O;
output ACK_O;
//--- Packet Generator interface
// RdData_o is always valid exactly one clock after Addr_o changes
// and Rd_o is asserted
output Rd_o;
output [13:0] Addr_o;
input [31:0] RdData_i;
//--- User (packet) interface
input Rx_mac_ra;
output Rx_mac_rd;
input [31:0] Rx_mac_data;
input [1:0] Rx_mac_BE;
input Rx_mac_pa;
input Rx_mac_sop;
input Rx_mac_err;
input Rx_mac_eop;
input Tx_mac_wa;
output Tx_mac_wr;
output [31:0] Tx_mac_data;
output [1:0] Tx_mac_BE;
output Tx_mac_sop;
output Tx_mac_eop;
//-------------------------------------------------------------------------
// Local declarations
//-------------------------------------------------------------------------
reg ACK_O;
reg [15:0] DAT_O;
reg Rd_o;
reg Tx_mac_wr;
reg [1:0] Tx_mac_BE;
reg Tx_mac_sop;
reg Tx_mac_eop;
//--- Wishbone interface --------------------------------------------------
reg [1:0] PG_CFG;
wire PG_Enable = PG_CFG[0];
always @( negedge Reset_n or posedge Clk )
if ( ~Reset_n )
begin
ACK_O <= 0;
DAT_O <= 'b0;
PG_CFG <= 2'h0;
end
else
begin
ACK_O <= 0;
if ( CYC_I & STB_I )
begin
ACK_O <= ~ACK_O; // Generate single cycle pulse!
if ( WE_I )
begin
PG_CFG <= DAT_I;
end
else
begin
DAT_O[1:0] <= PG_CFG;
end
end
end
//--- Packet Generator FSM ------------------------------------------------
parameter PG_FSM_STATE_IDLE = 3'h0;
parameter PG_FSM_STATE_LD_DESC_1 = 3'h1;
parameter PG_FSM_STATE_LD_DESC_2 = 3'h2;
parameter PG_FSM_STATE_RD_HEADER = 3'h3;
parameter PG_FSM_STATE_PAYLOAD_SEQ_NUMBER = 3'h4;
parameter PG_FSM_STATE_PAYLOAD = 3'h5;
parameter PG_FSM_STATE_DONE = 3'h6;
reg [2:0] PG_FSM_State;
reg [9:0] DescHigh; // Selects currente descriptor
reg [3:0] DescLow; // Index into a single descriptor (16 entries)
reg PDM_CFG1_LAST;
reg [3:0] PDM_CFG1_REPEAT;
reg [3:0] PDM_CFG1_HDRLEN;
reg [15:0] PDM_CFG2_PAYLDLEN;
reg [31:0] Tx_mac_data_reg;
reg WriteHeader;
reg [15:0] PayloadRemaining;
reg [31:0] PacketSequenceNumber;
reg [31:0] Payload;
always @( negedge Reset_n or posedge Clk )
if ( ~Reset_n )
begin
PG_FSM_State <= PG_FSM_STATE_IDLE;
Rd_o <= 0;
DescHigh <= 10'b0;
DescLow <= 4'b0;
Tx_mac_wr <= 0;
Tx_mac_sop <= 0;
Tx_mac_eop <= 0;
Tx_mac_BE <= 2'b00;
Tx_mac_data_reg <= 32'b0;
WriteHeader <= 0;
PayloadRemaining <= 16'd0;
PacketSequenceNumber <= 32'd0;
Payload <= 32'h0;
{ PDM_CFG1_HDRLEN, PDM_CFG1_REPEAT, PDM_CFG1_LAST, PDM_CFG2_PAYLDLEN } <= 'b0;
end
else
begin
casez ( PG_FSM_State )
PG_FSM_STATE_IDLE:
if ( PG_Enable )
begin
PG_FSM_State <= PG_FSM_STATE_LD_DESC_1;
Rd_o <= 1;
end
else
begin
DescHigh <= 10'b0;
DescLow <= 4'b0;
end
PG_FSM_STATE_LD_DESC_1:
begin
PG_FSM_State <= PG_FSM_STATE_LD_DESC_2;
DescLow <= DescLow + 1;
end
PG_FSM_STATE_LD_DESC_2:
begin
PG_FSM_State <= PG_FSM_STATE_RD_HEADER;
{ PDM_CFG1_LAST, PDM_CFG1_REPEAT, PDM_CFG1_HDRLEN, PDM_CFG2_PAYLDLEN } <=
{ RdData_i[31], RdData_i[23:20], RdData_i[19:16], RdData_i[15:0] };
end
PG_FSM_STATE_RD_HEADER:
begin
Tx_mac_wr <= 0;
if ( Tx_mac_wa )
begin
// Space in Tx FIFO - write next header word
DescLow <= DescLow + 1;
Tx_mac_wr <= 1;
Tx_mac_sop <= ( DescLow == 1 ); // Assert SOP on first header word
WriteHeader <= 1;
if ( DescLow == PDM_CFG1_HDRLEN )
begin
// The requested number of header words has been read
// - proceed to generate packet payload
PG_FSM_State <= PG_FSM_STATE_PAYLOAD_SEQ_NUMBER;
PayloadRemaining <= PDM_CFG2_PAYLDLEN;
end
end
end
PG_FSM_STATE_PAYLOAD_SEQ_NUMBER:
begin
WriteHeader <= 0;
Tx_mac_data_reg <= PacketSequenceNumber;
Tx_mac_wr <= 0;
Tx_mac_sop <= 0;
if ( Tx_mac_wa )
begin
Tx_mac_wr <= 1;
PG_FSM_State <= PG_FSM_STATE_PAYLOAD;
Payload <= 32'h01020304;
PayloadRemaining <= PayloadRemaining - 4;
end
end
PG_FSM_STATE_PAYLOAD:
begin
Tx_mac_data_reg <= Payload;
Tx_mac_wr <= 0;
if ( Tx_mac_wa )
begin
Tx_mac_wr <= 1;
Tx_mac_data_reg <= Payload;
Payload[31:24] <= Payload[31:24] + 8'h04;
Payload[23:16] <= Payload[23:16] + 8'h04;
Payload[15: 8] <= Payload[15: 8] + 8'h04;
Payload[ 7: 0] <= Payload[ 7: 0] + 8'h04;
PayloadRemaining <= PayloadRemaining - 4;
if ( PayloadRemaining <= 4 )
begin
PG_FSM_State <= PG_FSM_STATE_DONE;
Tx_mac_eop <= 1;
// Indicate how many bytes are valid in this last transfer
Tx_mac_BE <= PayloadRemaining[1:0];
end
end
end
PG_FSM_STATE_DONE:
begin
// TBD: Add support for REPEAT, NEXT & LAST!
Tx_mac_wr <= 0;
Tx_mac_eop <= 0;
end
endcase
end
//-------------------------------------------------------------------------
assign Tx_mac_data = WriteHeader ?
RdData_i : Tx_mac_data_reg;
assign Addr_o = { DescHigh, DescLow };
assign Rx_mac_rd = 0;
endmodule