3.5" inch TFT LCD Display Module 480X320 driven with FSMC.

TFT LCD Display Module 480X320 driven with FSMC

I have recently bought a 3.5" inch TFT LCD Touch Screen Display Module 480X320 with a www.mcufriend.com label on the back side. The display was equipped with an 8bit parallel interface. First I decided to test it with the UniGraphic library using the BUS_8 protocol. The display was very slow but improved when I switched to the PAR_8 protocol. Because I heard about the possibility to use a Flexible Static Memory Controller (FSMC), built into some STM MCU's, to drive LCD's (read/write to LCD's memory rather than to an external SRAM) I thought it would be a fun to try it out.

https://os.mbed.com/media/uploads/hudakz/lcd_3.5_tft_480x320_mcufriend_front.png

Below is the brief story of what I did:

  • Selected FSMC in the Connectivity category and configured it as below: https://os.mbed.com/media/uploads/hudakz/arch_max_fsmc_conf.png
  • Let the STM32CubeIDE generate the code (files).
  • Created a new program for the Seeed Arch Max target in the Mbed Online Compiler by selecting a mbed os blinky template.
  • Replaced the main.cpp with the main.c content of the STM32CubeIDE project.
  • Copy & Pasted the other files with codes from the STM32CubeIDE project to the online compiler project.
  • Renamed and modified:
    "stm32f4xx_it.h" to "stm32f4xx_it_msp.h"
    "stm32f4xx_it.c" to "stm32f4xx_it_msp.c"
  • Added the UniGraphic library to the online compiler project.
  • Extended the UniGraphic library with a FSMC_8 protocol and replaced the TFT::set_orientation(int orient) function with the one used by mcufriend for arduino.
  • Modified the main.cpp as needed.
https://os.mbed.com/media/uploads/hudakz/stm32f407vet6_st-link03.pnghttps://os.mbed.com/media/uploads/hudakz/lcd_3.5_tft_480x320_mcufriend_back.png


Wiring

STM32F407VETFT LCD module
+3.3V3V3
GNDGND
PB_12LCD_RST
GNDLCD_CS
PD_13 (RS)LCD_RS
PD_5 (WR)LCD_WR
PD_4 (RD)LCD_RD
PD_14 (DB00)LCD_D0
PD_15 (DB01)LCD_D1
PD_0 (DB02)LCD_D2
PD_1 (DB03)LCD_D3
PE_7 (DB04)LCD_D4
PE_8 (DB05)LCD_D5
PE_9 (DB06)LCD_D6
PE_10 (DB07)LCD_D7



Results
Execution times
Used protocolBUS_8FSMC_8
Operation \ Timemsms
Clear2283.98038.454
Plot192.06611.365
8bit BMP63.80541.338
Large Font163.8727.895
Sparce pixels2072.265/1458.05174.107/52.168
16bit BMP2288.58959.904
Revision:
0:fa952828e34c
diff -r 000000000000 -r fa952828e34c UniGraphic/Protocols/Protocols.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/UniGraphic/Protocols/Protocols.h	Sun May 10 10:44:31 2020 +0000
@@ -0,0 +1,166 @@
+ /* mbed UniGraphic library - Abstract protocol class
+ * Copyright (c) 2015 Giuliano Dianda
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+ 
+/** @file Protocols.h
+*/
+#ifndef Protocols_H
+#define Protocols_H
+
+#include "mbed.h"
+
+#define RGB24to16(r,g,b)  (((r&0xF8)<<8)|((g&0xFC)<<3)|((b&0xF8)>>3)) //5 red | 6 green | 5 blue
+#define BGR2RGB(color) (((color&0x1F)<<11) | (color&0x7E0) | ((color&0xF800)>>11))
+
+#define FLIP_NONE   0
+#define FLIP_X      1
+#define FLIP_Y      2
+
+//#define USE_CS
+
+/** Protocol types
+*/
+#include "platform.h"
+
+#if DEVICE_PORTINOUT
+enum proto_t {
+    PAR_8   /**< Parallel 8bit, port pins 0 to 7 */
+    ,PAR_16 /**< Parallel 16bit, port pins 0 to 15 */
+    ,BUS_8   /**< Parallel 8bit, scattered pins */
+    ,BUS_16   /**< Parallel 16bit, scattered pins */
+    ,SPI_8  /**< SPI 8bit */
+    ,SPI_16 /**< SPI 16bit */
+    ,I2C_   /**< I2C */
+    ,FSMC_8 /**< FSMC 8bit */
+};
+#else 
+enum proto_t {
+    BUS_8   /**< Parallel 8bit, scattered pins */
+    ,BUS_16   /**< Parallel 16bit, scattered pins */
+    ,SPI_8  /**< SPI 8bit */
+    ,SPI_16 /**< SPI 16bit */
+    ,I2C_   /**< I2C */
+};
+#endif
+
+
+/** Abstract interface class for spi and parallel protocols
+*/
+class Protocols
+{
+ public:
+    
+    /** Send 8bit command to display controller 
+    *
+    * @param cmd: byte to send  
+    *
+    */   
+    virtual void wr_cmd8(unsigned char cmd) = 0;
+    
+    /** Send 8bit data to display controller 
+    *
+    * @param data: byte to send   
+    *
+    */   
+    virtual void wr_data8(unsigned char data) = 0;
+    
+    /** Send 2x8bit command to display controller 
+    *
+    * @param cmd: halfword to send  
+    *
+    */   
+    virtual void wr_cmd16(unsigned short cmd) = 0;
+    
+    /** Send 2x8bit data to display controller 
+    *
+    * @param data: halfword to send   
+    *
+    */   
+    virtual void wr_data16(unsigned short data) = 0;
+    
+    /** Send 16bit pixeldata to display controller 
+    *
+    * @param data: halfword to send   
+    *
+    */   
+    virtual void wr_gram(unsigned short data) = 0;
+    
+    /** Send same 16bit pixeldata to display controller multiple times
+    *
+    * @param data: halfword to send
+    * @param count: how many
+    *
+    */   
+    virtual void wr_gram(unsigned short data, unsigned int count) = 0;
+    
+    /** Send array of pixeldata shorts to display controller
+    *
+    * @param data: unsigned short pixeldata array
+    * @param lenght: lenght (in shorts)
+    *
+    */   
+    virtual void wr_grambuf(unsigned short* data, unsigned int lenght) = 0;
+    
+    /** Read 16bit pixeldata from display controller (with dummy cycle)
+    *
+    * @param convert true/false. Convert 18bit to 16bit, some controllers returns 18bit
+    * @returns 16bit color
+    */ 
+    virtual unsigned short rd_gram(bool convert) = 0;
+    
+    /** Read 4x8bit register data (with dummy cycle)
+    * @param reg the register to read
+    * @returns data as uint
+    * 
+    */ 
+    virtual unsigned int rd_reg_data32(unsigned char reg) = 0;
+    
+    /** Read 3x8bit ExtendedCommands register data
+    * @param reg the register to read
+    * @param SPIreadenablecmd vendor/device specific cmd to read EXTC registers
+    * @returns data as uint
+    * @note EXTC regs (0xB0 to 0xFF) are read/write registers but needs special cmd to be read in SPI mode
+    */ 
+    virtual unsigned int rd_extcreg_data32(unsigned char reg, unsigned char SPIreadenablecmd) = 0;
+    
+    /** ILI932x specific, does a dummy read cycle, number of bits is protocol dependent
+    * for PAR protocols: a signle RD bit toggle
+    * for SPI8: 8clocks
+    * for SPI16: 16 clocks
+    */   
+    virtual void dummyread () = 0;
+    
+    /** ILI932x specific, select register for a successive write or read
+    *
+    * @param reg register to be selected
+    * @param forread false = a write next (default), true = a read next
+    * @note forread only used by SPI protocols
+    */   
+    virtual void reg_select(unsigned char reg, bool forread =false) = 0;
+    
+    /** ILI932x specific, write register with data
+    *
+    * @param reg register to write
+    * @param data 16bit data
+    */   
+    virtual void reg_write(unsigned char reg, unsigned short data) = 0;
+    
+    /** ILI932x specific, read register
+    *
+    * @param reg register to be read
+    * @returns 16bit register value
+    */ 
+    virtual unsigned short reg_read(unsigned char reg) = 0;
+    
+    /** HW reset sequence (without display init commands)   
+    */
+    virtual void hw_reset() = 0;
+    
+    /** Set ChipSelect high or low
+    * @param enable 0/1   
+    */
+    virtual void BusEnable(bool enable) = 0;
+
+};
+#endif