Module lcd_example::lib::lcd_utils

JHD162A LCD Driver [By: Jonathan Zurita]

Detailed Introduction

Welcome! This is the JHD162A LCD Driver documentation! There are three key components to this build:

• Initializing LCD display
• Writing static &str and char arrays to LCD
• Converting non-char types into characters

Each component will be explained in-depth, including design and implementation choices by the author

Question 1) Why convert float to a char array?

I personally believed that displaying certain float values such as ADC readings or other fine-tuned data could be proven useful. Therefore, I included a float-to-char function out of the box! However, the function float_to_array only supports up to 2 decimal places in accuracy.

Question 2) Why is it solely in 8-bit mode?

Originally, I started on developing a JHD162A LCD Driver for the STM32F4 series. I started development in 4-bit mode, saving precious gpio pins. However, I decided to take a different route and try out 8-bit mode for the LCD driver.Thankfully the 8-bit mode technically can transmit new characters at a faster rate. Depends mostly your situation (desired rate of data transmission).

Question 3) Are there next steps in development?

Possible next steps would be to implement a 4-bit mode. Another thing would be to create a example folder? lcd_example.rs should contain an example of analog pin 0 being read and displayed on LCD screen.

Constants

• ASCII_OFFSET 🔒
  Provided in order to convert u8 into proper ASCII char
• BIT_0 🔒
  BIT_0 through BIT_7 are bit masks in order to process the ASCII char parameter
• BIT_1 🔒
• BIT_2 🔒
• BIT_3 🔒
• BIT_4 🔒
• BIT_5 🔒
• BIT_6 🔒
• BIT_7 🔒
• D0_PIN 🔒
• D1_PIN 🔒
• D2_PIN 🔒
• D3_PIN 🔒
• D4_PIN 🔒
• D5_PIN 🔒
• D6_PIN 🔒
• D7_PIN 🔒
• ENABLE_PIN 🔒
• LED_PIN 🔒
  All pin macro numbers correspond to their respective index the in the gpio array in main()
• MAX_LENGTH 🔒
  Maximum length for one row of characters
• MS_DELAY 🔒
  Arbitrary value, user-defined
• READ_WRITE_PIN 🔒
• REGISTER_SEL 🔒

Functions

• clear_data_bits
  Clears all data pins (D0-D7)
• float_to_array
  Function converts a f32 into a [char] array in order to be processed by the LCD display
• reset_lcd
  Clears the LCD display, and sets the cursor back to the beginning
• test_write_char
  Fills whole LCD display with characters as a test
• write_char_array
  Writes a [char] array to the LCD display
• write_static_string
  Writes a static &str to the LCD display