HD44780
HD44780 | |
---|---|
Status | Stable
|
menuconfig | I/O->LCD Displays->HD44780 module driver (Character-LCD) |
Pinning | yes |
Ecmd | yes |
Control6 | yes |
Depends on | ECMD |
Requires | - |
Code | https://github.com/ethersex/ethersex/tree/master/hardware/lcd |
THIS WIKI PAGE IS CURRENTLY WORK IN PROGRESS
The HD44780 module provides support for common alphanumeric character LCDs using Hitachis HD44780 and compatible controllers.
Contents
Supported LC-Displays
The vast majority of all alphanumeric LC-Displays use Hitachis HD44780 dot matrix liquid crystal display (LCD) controller. The e6 HD44780 module supports displays of many different sizes utilizing the original HD44780 and compatible controllers.
Alphanumeric LCDs are mainly distinguished by their size, the start-address of the per line Display Data-RAM (DDRAM) and the controller type. The original HD44780 controllers can drive up to 80 characters - most displays with more characters use two independent controllers.
The following table lists the LC-displays supported by the e6 HD44780 module by size and per line DDRAM start-address:
Menuconfig | Size | DDRAM Startaddress | Note: | ||||
---|---|---|---|---|---|---|---|
LCD size/type | Characters | Lines | Line 1 | Line 2 | Line 3 | Line 4 | |
8_Characters_1_Line | 8 | 1 | 0x00 | n/a | n/a | n/a | |
16_Characters_1_Line | 16 | 1 | 0x00 | n/a | n/a | n/a | |
16_Characters_1_Line_Mux16 | 16 | 1 | 0x00 | n/a | n/a | n/a | organized as 8 chars, 2 lines |
20_Characters_1_Line | 20 | 1 | 0x00 | n/a | n/a | n/a | |
40_Characters_1_Line | 40 | 1 | 0x00 | n/a | n/a | n/a | |
8_Characters_2_Lines | 8 | 2 | 0x00 | 0x40 | n/a | n/a | |
12_Characters_2_Lines | 12 | 2 | 0x00 | 0x40 | n/a | n/a | |
16_Characters_2_Lines | 16 | 2 | 0x00 | 0x40 | n/a | n/a | |
20_Characters_2_Lines | 20 | 2 | 0x00 | 0x40 | n/a | n/a | |
24_Characters_2_Lines | 24 | 2 | 0x00 | 0x40 | n/a | n/a | |
40_Characters_2_Lines | 40 | 2 | 0x00 | 0x40 | n/a | n/a | |
16_Characters_4_Lines | 16 | 4 | 0x00 | 0x40 | 0x10 | 0x50 | |
20_Characters_4_Lines | 20 | 4 | 0x00 | 0x40 | 0x14 | 0x54 | Note DDRAM addresses |
20_Characters_4_Lines_KS0073 | 20 | 4 | 0x00 | 0x20 | 0x40 | 0x60 | Note DDRAM addresses |
27_Characters_4_Lines_2_EN | 27 | 4 | 0x00 | 0x40 | 0x00 | 0x40 | Two Enable-Pins/Controllers |
40_Characters_4_Lines_2_EN | 40 | 4 | 0x00 | 0x40 | 0x00 | 0x40 | Two Enable-Pins/Controllers |
Note: The HD44780 module drivers supports alphanumeric character LCDs only. Ethersex also has limited support for some graphical displays. Have a look at the LC-Display configuration.
Configuration
... │ │ Network ---> │ │ I/O ---> ... │ │ ADC / DAC ---> │ │ LCD Displays ---> ... │ │ [*] HD44780 module driver (Character-LCD) ---> │ │ [-] HR20-style LCD Display ... │ │ (16_Characters_2_Lines) LCD size/type │ │ (HD44780_Compat) LCD controller type │ │ (None) LCD charset conversion │ │ (I2C) Connection type │ │ (PCF8574) I2C Port Expander │ │ [*] Readback support │ │ [*] Backlight support │ │ [*] Backlight on at power-on │ │ [*] Invert Backlight switch
Configuration options:
- LCD size/type
- Select one of the defined display sizes and address configurations shown in the table #Supported LC-Displays above.
- Although it is technically possible to connect more than one display, the HD44780 module supports only one LC-Display at a time.
- LCD controller type
- Select LCD controller circuit:
-
- HD44780_Compat - most controllers are compatible to Hitachis HD44780
- KS0066U - Samsungs KS0066U requires a different init routine
- Almost all controllers for alphanumeric character LCDs are more or less HD44780-compatible at least at the feature- and function- level required by e6.
- If in doubt, choose HD44780_Compat.
- LCD charset conversion
- Select charset conversion used while writing to the lcd:
-
- None - use no charset conversion at all (safes program mem)
- HD44780_Compat - map characters from ISO8859-1 to the original HD44780 charset
- Allmost all controllers use their own non-ISO-compatible charset, varying between manufacturers, rom versions, etc. that provides characters from western languages as well as japanese, chinese and graphical glyphs.
- Charset conversion might become useful if you have to display messages and texts from external resources that uses standard encodings for their charset like ISO8859-1.
- Note: Charset conversion uses a lookup table and requires about 272 byte program memory (flash rom).
- Connection type
- Select the connection type for the LCD:
-
- Direct - direct connection using avr io-pins
- I2C - uses sub-selection of I2C port expander
- SER_LCD(74hct164) - serial connection using HCT164 shift register
- 2WIRE(74hct4094) - serial connection using HCT4094 shift register
- See section #Pinning below for further explanations.
- I2C Port Expander
- Select I2C Port Expander to use:
-
- PCF8574 - use PCF8574x as I2C port expander
- MCP23017 - use MCP23017 as I2C port expander
- Note: automatically enables I2C_MASTER_SUPPORT and I2C_PCF8574X_SUPPORT resp. I2C_MCP23017_SUPPORT when selected.
- Note: Selection is only valid when I2C was selected under Connection type.
- See section #Pinning below for further explanations.
- Readback support
- Enable support for bi-directional lcd bus to read LCDs busy flag. Supported by direct and I2C connection only.
- You definitly should use a readback capable hardware and enable this feature, saves lots of delays.
- Backlight support
- Backlight support for LCDs based on the HD44780 controller.
- Enable backlight on/off control via API and ECMD.
- Backlight on at power-on
- Switch on backlight at power-on/reset.
- Invert Backlight switch
- Invert backlight logic for low active backlight circuits e.g. found on Pollin AVR NET-IO Add-on.
Pinning
Direct
The following example maps the LCD pins to AVR port pins found on the 25 pin Sub-D connector of the Pollin AVR Net-IO board:
dnl Direct connection example dnl map LCD pins to Pollin AVR Net-IO dnl 25 pin extension port ifdef(`conf_HD44780', ` pin(HD44780_RS, PC4) pin(HD44780_RW, PC3) pin(HD44780_EN1, PC2) dnl pin(HD44780_EN2, PC5) pin(HD44780_D4, PA0) pin(HD44780_D5, PA1) pin(HD44780_D6, PA2) pin(HD44780_D7, PA3) ') ifdef(`conf_HD44780_BACKLIGHT', ` pin(HD44780_BL, PC6, OUTPUT) ')
I2C
/* * HD44780-Display über PCF8574 ansteuern. * Belegung Pollin Add-On-Board: * * Pin PCF8574 Pin am LCD * 4 (P0) -> 11 (DB4) * 5 (P1) -> 12 (DB5) * 6 (P2) -> 13 (DB6) * 7 (P3) -> 14 (DB7) * 9 (P4) -> 4 (RS) * 10 (P5) -> 5 (R/W) nicht benutzt ! * 11 (P6) -> 6 (EN) * 12 (P7) -> 15 (Beleuchtung) * * Die LCD-Beleuchtung an Pin 12 wird über einen * PNP-Transistor geschaltet. * Beleuchtung an: Bit 7=0 * Beleuchtung aus: Bit 7=1 * Die Address-Eingänge A0 bis A2 des PCF8574 liegen alle auf GND. * Die Basis-Addresse des Chips ist daher immer 0x20. */
Pinning:
ifelse(value_HD44780_CONNECTION,`HD44780_I2CSUPPORT',`dnl ifelse(value_HD44780_I2C_PORTEXP,`HD44780_I2C_PCF8574', `ifdef(`conf_HD44780_MULTIEN', `dnl dnl HD44780_PCF8574x_MULTI_MAPPING(ADR, RS, RW, EN1, EN2, DB4, DB5, DB6, DB7) HD44780_PCF8574x_MULTI_MAPPING(0x20, 4, 5, 6, 7, 0, 1, 2, 3)', `dnl dnl HD44780_PCF8574x_MAPPING(ADR, RS, RW, EN, DB4, DB5, DB6, DB7, BL) HD44780_PCF8574x_MAPPING(0x20, 4, 5, 6, 0, 1, 2, 3, 7)')', value_HD44780_I2C_PORTEXP,`HD44780_I2C_MCP23017', `ifdef(`conf_HD44780_MULTIEN', `dnl dnl HD44780_MCP23017_MULTI_MAPPING(ADR, PORT, RS, RW, EN1, EN2, DB4, DB5, DB6, DB7) HD44780_MCP23017_MULTI_MAPPING(0x24, B, 4, 5, 6, 7, 0, 1, 2, 3) HD44780_MCP23017_MULTI_MAPPING_BL(0x24, A, 7)', `dnl dnl HD44780_MCP23017_MAPPING(ADR, RS, RW, EN, DB4, DB5, DB6, DB7, BL) HD44780_MCP23017_MAPPING(0x24, B, 4, 5, 6, 0, 1, 2, 3, 7)')' )dnl ')dnl