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
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/UniGraphic/Protocols/SPI8.cpp	Sun May 10 10:44:31 2020 +0000
@@ -0,0 +1,208 @@
+ /* mbed UniGraphic library - SPI8 protocol class
+ * Copyright (c) 2015 Giuliano Dianda
+ * Released under the MIT License: http://mbed.org/license/mit
+ *
+ * Derived work of:
+ *
+ * mbed library for 240*320 pixel display TFT based on ILI9341 LCD Controller
+ * Copyright (c) 2013 Peter Drescher - DC2PD
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+ 
+#include "SPI8.h"
+
+
+SPI8::SPI8(int Hz, PinName mosi, PinName miso, PinName sclk, PinName CS, PinName reset, PinName DC)
+    : _CS(CS), _spi(mosi, miso, sclk), _reset(reset), _DC(DC)
+{
+    _reset = 1;
+    _DC=1;
+    _CS=1;
+    _spi.format(8,0);                  // 8 bit spi mode 0
+    _spi.frequency(Hz);
+    hw_reset();    
+}
+
+void SPI8::wr_cmd8(unsigned char cmd)
+{     
+    _DC.write(0); // 0=cmd
+    _spi.write(cmd);      // write 8bit
+    _DC.write(1); // 1=data next
+}
+void SPI8::wr_data8(unsigned char data)
+{
+    _spi.write(data);    // write 8bit
+}
+void SPI8::wr_cmd16(unsigned short cmd)
+{     
+    _DC.write(0); // 0=cmd
+    _spi.write(cmd>>8);      // write 8bit
+    _spi.write(cmd&0xFF);      // write 8bit
+    _DC.write(1); // 1=data next
+}
+void SPI8::wr_data16(unsigned short data)
+{
+    _spi.write(data>>8);    // write 8bit
+    _spi.write(data&0xFF);    // write 8bit
+}
+void SPI8::wr_gram(unsigned short data)
+{
+    _spi.write(data>>8);    // write 8bit
+    _spi.write(data&0xFF);    // write 8bit
+}
+void SPI8::wr_gram(unsigned short data, unsigned int count)
+{
+    if((data>>8)==(data&0xFF))
+    {
+        count<<=1;
+        while(count)
+        {
+            _spi.write(data);    // write 8bit
+            count--;
+        }
+    }
+    else
+    {
+        while(count)
+        {
+            _spi.write(data>>8);    // write 8bit
+            _spi.write(data&0xFF);    // write 8bit
+            count--;
+        }
+    }
+}
+void SPI8::wr_grambuf(unsigned short* data, unsigned int lenght)
+{
+    while(lenght)
+    {
+        _spi.write((*data)>>8);    // write 8bit
+        _spi.write((*data)&0xFF);    // write 8bit
+        data++;
+        lenght--;
+    }
+}
+unsigned short SPI8::rd_gram(bool convert)
+{
+    unsigned int r=0;
+    _spi.write(0); // whole first byte is dummy
+    r |= _spi.write(0);
+    r <<= 8;
+    r |= _spi.write(0);
+    if(convert)
+    {
+        r <<= 8;
+        r |= _spi.write(0);
+        // gram is 18bit/pixel, if you set 16bit/pixel (cmd 3A), during writing the 16bits are expanded to 18bit
+        // during reading, you read the raw 18bit gram
+        r = RGB24to16((r&0xFF0000)>>16, (r&0xFF00)>>8, r&0xFF);// 18bit pixel padded to 24bits, rrrrrr00_gggggg00_bbbbbb00, converted to 16bit
+    } 
+    _CS = 1; // force CS HIG to interupt the "read state"
+    _CS = 0;
+    return (unsigned short)r;
+}
+unsigned int SPI8::rd_reg_data32(unsigned char reg)
+{
+    wr_cmd8(reg);
+    unsigned int r=0;
+   
+    r |= _spi.write(0); // we get only 7bit valid, first bit was the dummy cycle
+    r <<= 8;
+    r |= _spi.write(0);
+    r <<= 8;
+    r |= _spi.write(0);
+    r <<= 8;
+    r |= _spi.write(0);
+    r <<= 1; // 32bits are aligned, now collecting bit_0
+    r |= (_spi.write(0) >> 7);
+    // we clocked 7 more bit so ILI waiting for 8th, we need to reset spi bus
+    _CS = 1; // force CS HIG to interupt the cmd
+    _CS = 0;
+    return r;
+}
+unsigned int SPI8::rd_extcreg_data32(unsigned char reg, unsigned char SPIreadenablecmd)
+{
+    unsigned int r=0;
+    for(int regparam=1; regparam<4; regparam++) // when reading EXTC regs, first parameter is always dummy, so start with 1
+    {
+        wr_cmd8(SPIreadenablecmd);  // spi-in enable cmd, 0xD9 (ili9341) or 0xFB (ili9488) or don't know
+        wr_data8(0xF0|regparam);    // in low nibble specify which reg parameter we want
+        wr_cmd8(reg);               // now send cmd (select register we want to read)
+        r <<= 8;
+        r |= _spi.write(0);
+        // r = _spi.write(0) >> 8; for 16bit
+    }
+    _CS = 1; // force CS HIG to interupt the cmd
+    _CS = 0;
+    return r;
+}
+// ILI932x specific
+void SPI8::dummyread()
+{
+    _spi.write(0);    // dummy read
+}
+// ILI932x specific
+void SPI8::reg_select(unsigned char reg, bool forread)
+{
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    _spi.write(0x70);
+    _spi.write(0);    // write MSB
+    _spi.write(reg);    // write LSB
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    if(forread) _spi.write(0x73);
+    else _spi.write(0x72);
+}
+// ILI932x specific
+void SPI8::reg_write(unsigned char reg, unsigned short data)
+{
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    _spi.write(0x70);
+    _spi.write(0);    // write MSB
+    _spi.write(reg);    // write LSB
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    _spi.write(0x72);
+    _spi.write(data>>8);
+    _spi.write(data&0xFF);
+}
+// ILI932x specific
+unsigned short SPI8::reg_read(unsigned char reg)
+{
+    unsigned short r=0;
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    _spi.write(0x70);
+    _spi.write(0);    // write MSB
+    _spi.write(reg);    // write LSB
+    _CS = 1;    //fixme: really needed?
+    _CS = 0;    //fixme: really needed?
+    _spi.write(0x73);
+    _spi.write(0);    // dummy read
+    r = _spi.write(0);    // read 8bit
+    r <<= 8;
+    r |= _spi.write(0);    // read 8bit
+    return r;
+}
+void SPI8::hw_reset()
+{
+    wait_ms(15);
+    _DC = 1;
+    _CS = 1;
+    _reset = 0;                        // display reset
+    wait_ms(2);
+    _reset = 1;                       // end reset
+    wait_ms(100);
+}
+void SPI8::BusEnable(bool enable)
+{
+    _CS = enable ? 0:1;
+}
\ No newline at end of file