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enabling Grove - 16x2 LCD (JHD1804) #136

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enabling Grove - 16x2 LCD (JHD1804) #136

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03252fb
enabling Grove - 16x2 LCD (JHD1804)
wsad4ryba Jul 11, 2024
0343f86
update readme
wsad4ryba Jul 11, 2024
a6e331f
fix typo
wsad4ryba Jul 11, 2024
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3 changes: 3 additions & 0 deletions README.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -92,6 +92,7 @@ Supported I²C Port Expanders
- PCF8574 (used by a lot of I²C LCD adapters on Ali Express)
- MCP23008 (used in Adafruit I²C LCD backpack)
- MCP23017
- JHD1804 (with AIP31068L controller, used in Grove - 16x2 LCD)


Documentation
Expand Down Expand Up @@ -147,6 +148,8 @@ Resources
- TC2004A-01 Data Sheet: http://www.adafruit.com/datasheets/TC2004A-01.pdf
- HD44780U Data Sheet: http://www.adafruit.com/datasheets/HD44780.pdf
- ST7066 Data Sheet: https://www.sparkfun.com/datasheets/LCD/st7066.pdf
- JHD1804 Data Sheet: https://raw.githubusercontent.com/SeeedDocument/Grove-16x2_LCD_Series/master/res/JDH_1804_Datasheet.pdf
- AIP31068L Data Sheet: https://www.orientdisplay.com/wp-content/uploads/2022/08/AIP31068L.pdf


License
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8 changes: 7 additions & 1 deletion RPLCD/i2c.py
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Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,7 @@ def __init__(self, i2c_expander, address, expander_params=None, port=1,
self._port = port

# Set i2c expander, 'PCF8574', 'MCP23008' and 'MCP23017' are supported.
if i2c_expander in ['PCF8574', 'MCP23008', 'MCP23017']:
if i2c_expander in ['PCF8574', 'MCP23008', 'MCP23017', "JHD1804"]:
self._i2c_expander = i2c_expander
else:
raise NotImplementedError('I2C expander "%s" is not supported.' % i2c_expander)
Expand Down Expand Up @@ -230,6 +230,9 @@ def _send_data(self, value):
self._mcp_data |= MCP230XX_RS
self._pulse_data(value >> 4)
self._pulse_data(value & 0x0F)
elif self._i2c_expander == 'JHD1804':
self.bus.write_byte_data(self._address, 0xC0, value)
c.usleep(100)

def _send_instruction(self, value):
if self._i2c_expander == 'PCF8574':
Expand All @@ -243,6 +246,9 @@ def _send_instruction(self, value):
self._mcp_data &= ~MCP230XX_RS
self._pulse_data(value >> 4)
self._pulse_data(value & 0x0F)
elif self._i2c_expander == 'JHD1804':
self.bus.write_byte_data(self._address, 0x80, value)
c.usleep(100)

def _pulse_data(self, value):
"""Pulse the `enable` flag to process value."""
Expand Down
37 changes: 19 additions & 18 deletions RPLCD/lcd.py
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Expand Up @@ -94,24 +94,25 @@ def __init__(self, cols=20, rows=4, dotsize=8, charmap='A02', auto_linebreaks=Tr
self._init_connection()

# Choose 4 or 8 bit mode
if self.data_bus_mode == c.LCD_4BITMODE:
# Hitachi manual page 46
self.command(0x03)
c.msleep(4.5)
self.command(0x03)
c.msleep(4.5)
self.command(0x03)
c.usleep(100)
self.command(0x02)
elif self.data_bus_mode == c.LCD_8BITMODE:
# Hitachi manual page 45
self.command(0x30)
c.msleep(4.5)
self.command(0x30)
c.usleep(100)
self.command(0x30)
else:
raise ValueError('Invalid data bus mode: {}'.format(self.data_bus_mode))
if self._i2c_expander != 'JHD1804':
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Why is this not applicable to the JHD1804? The way I understand it, a port expander only forwards the commands to the hitachi chip.

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Also, this line doesn't work, see tests

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this is not an ordinary i2c expander, but a full driver with built-in i2c, a replacement for the hitachi chip, usually compatible, but the initialization looks different because you do not need to set the 4 or 8 bit communication function:
obraz

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this line doesn't work in tests, but it works in reality. the value of _i2c_expander comes from the CharLCD class, the same as e.g. in the next line if self.data_bus_mode == c.LCD_4BITMODE:, with the difference that data_bus_mode is always defined self.data_bus_mode = c.LCD_4BITMODE (line 153 in i2c.py) while the expander must be defined when creating the object:

if i2c_expander in ['PCF8574', 'MCP23008', 'MCP23017', 'JHD1802']:
 self._i2c_expander = i2c_expander
 else:
 raise NotImplementedError('I2C expander "%s" is not supported.' % i2c_expander)

(i2c.py 131 to 134)
I don't see an expander defined anywhere in the tests, but the object creation still goes through?

if self.data_bus_mode == c.LCD_4BITMODE:
# Hitachi manual page 46
self.command(0x03)
c.msleep(4.5)
self.command(0x03)
c.msleep(4.5)
self.command(0x03)
c.usleep(100)
self.command(0x02)
elif self.data_bus_mode == c.LCD_8BITMODE:
# Hitachi manual page 45
self.command(0x30)
c.msleep(4.5)
self.command(0x30)
c.usleep(100)
self.command(0x30)
else:
raise ValueError('Invalid data bus mode: {}'.format(self.data_bus_mode))

# Write configuration to display
self.command(c.LCD_FUNCTIONSET | displayfunction)
Expand Down
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