PV198 - LCD
One-chip Controllers
Daniel Dlhopolček, Marek Vrbka, Jan Koniarik, Oldřich Pecák,
Tomáš Rohlínek, Ján Labuda, Jan Horáček, Matúš Škvarla, Ondřej Bleha,
Martin Klimeš, Adam Valt
Faculty of Informatics, Masaryk University
11/2024
Introduction
Intro
Switch the branch to Week_11!
Discussion of HW9
·PV198 - LCD ·11/2024 2 / 12
LCD
LCD
LCD = Liquid Crystal Display
Usage
Printers
Routers
Industrial equipment
Consumer equipment – washing machines, ...
...
·PV198 - LCD ·11/2024 3 / 12
LCD 1602A
LCD 1602A
Display for 16×2 characters
HD44780U Display Controller – datasheet
Basic connection:
DB4–DB7 (4-bit parallel transfer)
RS — Register Select
R/W – Read/Write select
E – Starts data read/write
·PV198 - LCD ·11/2024 4 / 12
LCD 1602A
Message
·PV198 - LCD ·11/2024 5 / 12
LCD 1602A
FRDM-K66F – LCD 1602A Connection
FRDM-K66F LCD 1602A
GND GND 1 VSS
P5V_USB 5V 2 VDD
DAC0_OUT DAC0_OUT 3 V0
PTA27 LCD_RS 4 RS
PTA26 LCD_RW 5 R/W
PTA4 LCD_E 6 E
PTA6 LCD_DB4 11 DB4
PTA7 LCD_DB5 12 DB5
PTA8 LCD_DB6 13 DB6
PTA9 LCD_DB7 14 DB7
Digital-to-Analog-Converter (DAC) is used to control LCD contrast.
Use pins A (anode – connect to 3V3) & K (cathode – connect to GND)
to drive backlight.
·PV198 - LCD ·11/2024 6 / 12
Driver
Driver
Support for 4bit communication initialization
SysTick timer used for delays
Basic command and data transfer functions
Does not read busy flag – uses delays instead
·PV198 - LCD ·11/2024 7 / 12
Driver
Driver Pins
The LCD driver requires to define the following identifiers in the Pins
tool for GPIO output pins: LCD_RS, LCD_RW, LCD_E, LCD_DB4,
LCD_DB5, LCD_DB6, LCD_DB7.
·PV198 - LCD ·11/2024 8 / 12
Driver
Driver Interface
void LCD_4BitsInit(uint32_t systick_clk_freq,
bool cursor_on, bool cursor_blinking)
void LCD_Clear()
void LCD_Home()
void LCD_SetPosition(uint8_t x, uint8_t y)
void LCD_PutChar(uint8_t character)
void LCD_Print(char s[])
void LCD_SendCommand(uint8_t command)
void LCD_SendData(uint8_t data, MessageType_t messageType)
·PV198 - LCD ·11/2024 9 / 12
Seminar task
Template
Real date and time display demo
Download from study materials
Content:
LCD driver initialization
RTC peripheral initialization
while loop: obtain current date & time, print on display
·PV198 - LCD ·11/2024 10 / 12
Seminar task
Seminar task
Implement a function LCD_SendData according to the
message format picture.
void LCD_SendData(uint8_t data,
MessageType_t messageType)
Bonus: display floating text on the display.
·PV198 - LCD ·11/2024 11 / 12
Homework
Homework
Generate something else on the LCD string (be creative).
Tests check for initialization and if there is something on the
screen.
Avoid adding drivers, they will break the project.
·PV198 - LCD ·11/2024 12 / 12