Tang Nano 20K: I2C OLED Driver
- 写在前面的话
- 硬件模块
- RTL电路和相关资源报告
- SSD1306 OLED 驱动芯片
- SSD1306 I2C协议接口
- OLED 驱动模块RTL
- 综合实现
- 总结
写在前面的话
- 之前在逛淘宝的时候偶然发现了Tang Nano 20K,十分感慨国产FPGA替代方案的进步之快;
- 被Tang Nano 20K小巧精致的外形和丰富的内在资源震惊到了,买来想要体验一下国产FPGA的软件生态。
硬件模块
- 项目主要设备是高云半导体的Tang Nano 20K开发板和0.96寸四针I2C模块的OLED模块;
- OLED模块采用SSD1306驱动芯片;
Tang Nano 20K
0.96寸 I2C 接口OLED
RTL电路和相关资源报告
- 采用GOWIN FPGA Designer平台查看RTL电路图;
- 采用GOWIN FPGA Designer平台查看资源报告;
SSD1306 OLED 驱动芯片
- SSD1306是一个单片CMOS OLED/PLED驱动芯片可以驱动有机/聚合发光二极管点阵图形显示系统。由128 segments和64Commons组成。该芯片专为共阴极OLED面板设计。
- SSD1306中嵌入了对比度控制器、显示RAM和晶振,并因此减少了外部器件和功耗。有256级亮度控制。数据/命令的发送有三种接口可选择:6800/8000串口,I2C接口或SPI接口。适用于多数简介的应用,移动电话的屏显,MP3播放器和计算器等。
SSD1306 芯片框图
SSD1306中内置128 * 64的GDDRAM,是一个为映射静态RAM保存位模式来显示,RAM分为8页,从PAFE0到PAGE7,用于单色128 * 64点阵显示,如下图所示:
GDDRAM:
当一个数据字节写到GDDRAM中,所有当前列的同一页的行图像数据都会被被填充(比如,被列地址指针指向的整列(8位)都会被填充)。数据位D0写到顶行,而数据位D7写到底行,如下图所示。
SSD1306 I2C协议接口
I2C通讯接口由从机地址为SA0,I2C总线数据信号(SDAout/D2输出和SDAin/D1输入)和I2C总线时钟信号SCL(D0)组成。数据和时钟信号线都必须接上上拉电阻。RES#用来初始化设备。
I2C数据格式:
a. 从机地址位(SA0)
SSD1306在发送或接受任何信息之前必须识别从机地址。设备将会响应从机地址,后面跟随着从机地址位(SA0位)和读写选择位(R/W#位)。
SA0位为从机地址提供了一个位的拓展。0111100或0111101都可以做为SSD1306的从机地址。D/C#引脚作为SA0用于从机地址选择。R/W#为用来决定I2C总线接口的操作模式。R/W# = 1,读模式。R/W# = 0 写模式
b. I2C总线数据信号SDA
SDA作为主机和从机之间的通讯通道。数据和应答都是通过SDA发送。
c. I2C总线时钟信号SCL
每个数据位的传输任务发生在SCL的单个的时钟周期中。
项目难度:⭐
项目推荐度:⭐⭐
项目推荐天数:1~天
FPGA开发环境:
前仿: Modelsim SE-64 2019.2
综合: Gowin_V1.9.9Beta-4_Education
项目学习目的:
(1)熟练掌握项目中各文件的工程管理;
(2)熟悉 Verilog HDL仿真、FPGA综合工具及流程;
(3)学习OLED 驱动和I2C的基础原理;
OLED 驱动模块RTL
//oled_init 初始化模块
module OLED_Init(
input sys_clk ,
input rst_n ,
input init_req , //初始化请求
input write_done , //初始化数据完成信号
output init_finish , //初始化完成输出
output[23:0] Init_data //初始化的数据
);
//WR CMD : 0X78+0X00+CMD
//WR Data: 0X78+0X40+Data
localparam RST_T = 1'b0; //低电平复位有效
reg[23:0] Init_data_reg;
reg[23:0] Init_data_reg1;
reg[4:0] Init_index;
reg init_finish_inside;
//OLED_WR
reg [10:0] WR_index ; //TX data counter
reg [9:0] WR_addr ; //TX ROM Data addr
wire [7:0] WR_data ; //WR Data
//FSM
localparam IDLE = 2'b01 ;
localparam WR = 2'b10 ;
reg [1:0] CS ;
reg [1:0] NS ;
always @(posedge sys_clk or negedge rst_n) begin
if(~rst_n) begin
CS <= IDLE;
end
else begin
CS <= NS;
end
end
always@(*) begin
case(CS)
IDLE: begin
if(Init_index >= 'd26 && write_done == 1'b1) begin
NS = WR;
end
else begin
NS = IDLE;
end
end
WR: begin
if(rst_n==1'b0) begin
NS = IDLE;
end
else begin
NS = WR;
end
end
default: NS = IDLE;
endcase
end
always@(*) begin
case(CS)
IDLE: init_finish_inside = 1'b0;
WR: init_finish_inside = 1'b1;
default: NS = IDLE;
endcase
end
assign Init_data = (init_finish_inside==1'b1)?Init_data_reg1:Init_data_reg;
assign init_finish = (write_done == 1'b1 && WR_index == 'd1047) ? 1'b1 : 1'b0;//完成信号
always@(posedge sys_clk or negedge rst_n)
begin
if(rst_n == RST_T)
Init_index <= 'd0;
else if(Init_index == 'd26 && write_done == 1'b1 )
Init_index <= 'd0;
else if(write_done == 1'b1 && init_req == 1'b1)
Init_index <= Init_index + 1'b1;
else
Init_index <= Init_index;
end
//初始化命令状态
always@(*)
begin
case(Init_index)
'd0: Init_data_reg <= {8'h78,8'h00,8'hAE};
'd1: Init_data_reg <= {8'h78,8'h00,8'h00};
'd2: Init_data_reg <= {8'h78,8'h00,8'h10};
'd3: Init_data_reg <= {8'h78,8'h00,8'h40};
'd4: Init_data_reg <= {8'h78,8'h00,8'hB0};
'd5: Init_data_reg <= {8'h78,8'h00,8'h81};
'd6: Init_data_reg <= {8'h78,8'h00,8'hFF};
'd7: Init_data_reg <= {8'h78,8'h00,8'hA1};
'd8: Init_data_reg <= {8'h78,8'h00,8'hA6};
'd9: Init_data_reg <= {8'h78,8'h00,8'hA8};
'd10: Init_data_reg <= {8'h78,8'h00,8'h3F};
'd11: Init_data_reg <= {8'h78,8'h00,8'hC8};
'd12: Init_data_reg <= {8'h78,8'h00,8'hD3};
'd13: Init_data_reg <= {8'h78,8'h00,8'h00};
'd14: Init_data_reg <= {8'h78,8'h00,8'hD5};
'd15: Init_data_reg <= {8'h78,8'h00,8'h80};
'd16: Init_data_reg <= {8'h78,8'h00,8'hD8};
'd17: Init_data_reg <= {8'h78,8'h00,8'h05};
'd18: Init_data_reg <= {8'h78,8'h00,8'hD9};
'd19: Init_data_reg <= {8'h78,8'h00,8'hF1};
'd20: Init_data_reg <= {8'h78,8'h00,8'hDA};
'd21: Init_data_reg <= {8'h78,8'h00,8'h12};
'd22: Init_data_reg <= {8'h78,8'h00,8'hDB};
'd23: Init_data_reg <= {8'h78,8'h00,8'h30};
'd24: Init_data_reg <= {8'h78,8'h00,8'h8D};
'd25: Init_data_reg <= {8'h78,8'h00,8'h14};
'd26: Init_data_reg <= {8'h78,8'h00,8'hAF};
default:
Init_data_reg <= {8'h78,8'h00,8'hAE};
endcase
end
always @(posedge sys_clk or negedge rst_n)
begin
if(~rst_n)begin
WR_index <= 11'd0;
end
else if(WR_index == 'd1048) begin
WR_index <= 11'd0;
end
else if(init_finish_inside == 1'b1 && write_done == 1'b1 && init_req == 1'b1)
WR_index <= WR_index + 1'b1;
else
WR_index <= WR_index;
end
always @(posedge sys_clk or negedge rst_n)
begin
if(~rst_n)
begin
WR_addr <= 10'd0;
end
else
begin
if ((WR_index >= 11'd2) && (WR_index <= 11'd129))
begin
WR_addr <= WR_index - 11'd2;
end
else if ((WR_index >= 11'd133) && (WR_index <= 11'd260))
begin
WR_addr <= WR_index - 11'd5;
end
else if ((WR_index >= 11'd264) && (WR_index <= 11'd391))
begin
WR_addr <= WR_index - 11'd8;
end
else if ((WR_index >= 11'd395) && (WR_index <= 11'd522))
begin
WR_addr <= WR_index - 11'd11;
end
else if ((WR_index >= 11'd526) && (WR_index <= 11'd653))
begin
WR_addr <= WR_index - 11'd14;
end
else if ((WR_index >= 11'd657) && (WR_index <= 11'd784))
begin
WR_addr <= WR_index - 11'd17;
end
else if ((WR_index >= 11'd788) && (WR_index <= 11'd915))
begin
WR_addr <= WR_index - 11'd20;
end
else if ((WR_index >= 11'd919) && (WR_index <= 11'd1046))
begin
WR_addr <= WR_index - 11'd23;
end
end
end
//初始化数据发送
always@(*) begin
case (WR_index)
11'd0: Init_data_reg1 <= {8'h78,8'h00,8'hB0};
11'd1: Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd2: Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 0
11'd131:Init_data_reg1 <= {8'h78,8'h00,8'hB1};
11'd132:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd133:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 1
11'd262:Init_data_reg1 <= {8'h78,8'h00,8'hB2};
11'd263:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd264:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 2
11'd393:Init_data_reg1 <= {8'h78,8'h00,8'hB3};
11'd394:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd395:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 3
11'd524:Init_data_reg1 <= {8'h78,8'h00,8'hB4};
11'd525:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd526:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 4
11'd655:Init_data_reg1 <= {8'h78,8'h00,8'hB5};
11'd656:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd657:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 5
11'd786:Init_data_reg1 <= {8'h78,8'h00,8'hB6};
11'd787:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd789:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 6
11'd917:Init_data_reg1 <= {8'h78,8'h00,8'hB7};
11'd918:Init_data_reg1 <= {8'h78,8'h00,8'h00};
11'd919:Init_data_reg1 <= {8'h78,8'h00,8'h10};
// page 7
default : Init_data_reg1 <= {8'h78,8'h40,WR_data}; //binary data
endcase
end
assign WR_data = 8'hAA;
//Change the instance name and port connections to the signal names
//--------Copy here to design--------
Gowin_pROM your_instance_name(
.dout (WR_data ), //output [7:0] dout
.clk (sys_clk ), //input clk
.oce ( ), //input oce
.ce (1'b1 ), //input ce
.reset (~rst_n ), //input reset
.ad (WR_addr ) //input [9:0] ad
);
//--------Copy end-------------------
endmodule
综合实现
采用GOWIN完成电路综合,并下板实现。
祝大家新年快乐呀
总结
没啥总结的,在这里祝愿大家龙年大吉,万事如意!