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Connectors and User Components
Access cycle 1: Write LCD control bits RS, R/W, LCD data byte. LCD1 and 2 select bits = 0.
Access cycle 2: Write LCD control bits LCD1 select, LCD2 select active as required. RS, R/W,
LCD data byte values do not change but must be written again.
Access cycle 3 = READ: Read LCD Port if a Read access type, determined by R/W = 1 in first
access cycles.
Access cycle 3 = WRITE: Write LCD control bits LCD1 select, LCD2 select idle. RS, R/W, LCD
data byte do not change but must be written again. This terminates a Write access sequence.
Access cycle 4 = READ end: Write LCD control bits LCD1 select, LCD2 select idle, RS, R/W bits
do not change but must be written again. This terminates a Read access sequence.
Table 1-9. LCD PORT REGISTER Definition (MPC500 core register aligned)
BIT #
FUNCTION
D0
LCD1 select, 80 character or first 80 characters of 160 character module select. 1 = Active
D1
LCD2 select, second 80 characters of 160 character module select. 1 = Active
D2 – D5
N/A, not applied
D6
LCD RS or Register Select. 0 = Command, 1 = Display Data access
D7
LCD Read / Write select. 0 = Write, 1 = Read access
D8 > D15
LCD Data Byte D7 > D0, Write output to LCD if D7 = 0, Read input if D7 = 1.
See LCD Module data sheet for command codes
Example source code for the LCD and Keypad drivers are provided on the Axiom MPC5xx support
CD. The LCD Port is assigned on chip select CS3 if enabled with MAP Switch position 6. Memory
map offset for the LCD Port = CS3 base + 0x0010.
LCD Display CONTRAST
The CONTRAST adjustment allows a contrast Vee voltage to be presented to the LCD_PORT of
–5V to +5V DC.
JP2 - LCD_PORT Power Polarity Select
JP2 determines the display power pin polarity on the LCD_PORT. Depending on the type and
location of the IDC connector on your display module, the power connections may need to be
reversed. Care should be used to verify proper connection and signal matching at the IDC Cable
Connector and LCD_PORT.
See the schematic to match this jumper setting to your LCD device connector. Contact
support@axman.com for assistance applying a LCD module.
Typical JP2 positions for 80 character or smaller LCD. Rotate 90 degrees for 160
character type modules.
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MPC564EVB User's Manual
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