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oled_spi.v
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oled_spi.v
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`default_nettype none
`timescale 1ns / 1ps
module oled_spi(
input wire clock,
input wire reset,
input wire shutdown,
output wire cs,
output reg sdin,
output wire sclk,
output reg dc,
output reg res,
output reg vbatc,
output reg vddc
);
parameter WAIT = 1;
parameter SEND = 2; // send 1 byte
parameter SEND2 = 3; // send 2 bytes
parameter SEND3 = 4; // send 3 bytes
parameter SEND4 = 5; // send 4 bytes
parameter STARTUP_1 = 10;
parameter STARTUP_2 = 11;
parameter STARTUP_3 = 12;
parameter STARTUP_4 = 13;
parameter STARTUP_5 = 14;
parameter STARTUP_6 = 15;
parameter STARTUP_7 = 16;
parameter STARTUP_8 = 17;
parameter STARTUP_9 = 18;
parameter SHUTDOWN_1 = 6;
parameter SHUTDOWN_2 = 7;
parameter SHUTDOWN_3 = 8;
reg [31:0] send_buf;
reg [4:0] send_idx;
reg [1:0] send_ctr;
reg [1:0] send_max;
reg [31:0] wait_ctr;
reg [31:0] wait_max;
// TODO probably don't need 7 bits for state
reg [7:0] state;
reg [7:0] next_state;
always @(posedge clock) begin
// RESET
if (reset) begin
send_buf <= 32'b0;
send_idx <= 5'b0;
send_ctr <= 2'b0;
send_max <= 2'b0;
wait_ctr <= 32'b0;
wait_max <= 32'b0;
state <= STARTUP_1;
next_state <= 1'b0;
sdin <= 1'b0;
dc <= 1'b0;
res <= 1'b1;
vddc <= 1'b1;
vbatc <= 1'b1;
end
// SHUTDOWN
else if (shutdown) begin
if (state > 0 && state < 10) begin
next_state <= SHUTDOWN_1;
end else begin
state <= SHUTDOWN_1;
end
end
// STATES
else begin
// SEND - send up to four serial bytes
if (state == SEND) begin
sdin <= send_buf[(7 - send_idx) + (8 * send_ctr)];
if (send_idx == 7 && send_ctr == send_max) begin
send_idx <= 0;
send_ctr <= 0;
send_max <= 0;
state <= next_state;
end else if (send_idx == 7) begin
send_idx <= 0;
send_ctr <= send_ctr + 1;
end else begin
send_idx <= send_idx + 1;
end
end
// SEND2 - send two bytes
if (state == SEND2) begin
send_max = 1;
state <= SEND;
end
// SEND3 - send three bytes
else if (state == SEND3) begin
send_max = 2;
state <= SEND;
end
// SEND4 - send four bytes
else if (state == SEND4) begin
send_max = 3;
state <= SEND;
end
// WAIT - wait for # of cycles
else if (state == WAIT) begin
if (wait_ctr == wait_max) begin
wait_ctr <= 0;
state <= next_state;
end else begin
wait_ctr <= wait_ctr + 1;
end
end
// STARTUP_1 -- apply power to VDD
else if (state == STARTUP_1) begin
dc <= 0;
vddc <= 0;
wait_max <= 5000; // 1ms
state <= WAIT;
next_state <= STARTUP_2;
end
// STARTUP_2 -- send display off cmd
else if (state == STARTUP_2) begin
send_buf <= 8'hAE;
state <= SEND;
next_state <= STARTUP_3;
end
// STARTUP_3 -- clear screen
else if (state == STARTUP_3) begin
res <= 0;
wait_max <= 5000; // 1ms
state <= WAIT;
next_state <= STARTUP_4;
end
// STARTUP_4 -- set charge pump
else if (state == STARTUP_4) begin
res <= 1;
send_buf <= 16'h148D;
state <= SEND2;
next_state <= STARTUP_5;
end
// STARTUP_5 -- set pre-charge period
else if (state == STARTUP_5) begin
send_buf <= 16'hF1D9;
state <= SEND2;
next_state <= STARTUP_6;
end
// STARTUP_6 -- apply power to VBAT
else if (state == STARTUP_6) begin
vbatc <= 0;
wait_max <= 500000; // 100ms
state <= WAIT;
next_state <= STARTUP_7;
end
// STARTUP_7 -- invert the display
else if (state == STARTUP_7) begin
send_buf <= 16'hC8A1;
state <= SEND2;
next_state <= STARTUP_8;
end
// STARTUP_8 -- select squential COM configuration
else if (state == STARTUP_8) begin
send_buf <= 16'h20DA;
state <= SEND2;
next_state <= STARTUP_9;
end
// STARTUP_9 -- send display on cmd
else if (state == STARTUP_9) begin
send_buf <= 8'hAF;
state <= SEND;
next_state <= 0; // TODO
end
// SHUTDOWN_1 -- send display off cmd
else if (state == SHUTDOWN_1) begin
send_buf <= 8'hAE;
state <= SEND;
next_state <= SHUTDOWN_2;
end
// SHUTDOWN_2 -- turn off VBAT
else if (state == SHUTDOWN_2) begin
vbatc <= 1;
wait_max <= 500000; // 100ms
state <= WAIT;
next_state <= SHUTDOWN_3;
end
// SHUTDOWN_4 -- turn off VDD
else if (state == SHUTDOWN_3) begin
vddc <= 1;
state <= 0; // TODO
end
end
end
assign cs = 0;
assign sclk = !clock;
endmodule