Operation; Four-Bit Data Interface - Xilinx MIcroBlaze Development Spartan-3E 1600E Kit User Manual

Chapter 5: Character LCD Screen
After the write operation, the address is automatically incremented or decremented by 1
according to the
Execution Time: 40 s
Read Data from CG RAM or DD RAM
Read data from DD RAM if the command follows a previous
command, or read data from CG RAM if the command follows a previous
Address
After the read operation, the address is automatically incremented or decremented by 1
according to the
during read operations.
Execution Time: 40 s

Operation

Four-Bit Data Interface

The board uses a 4-bit data interface to the character LCD.
Figure 5-6
for setup, hold, and enable pulse length relative to the 50 MHz clock (20 ns period)
provided on the board.
50
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Entry Mode Set
command.
Entry Mode Set
illustrates a write operation to the LCD, showing the minimum times allowed
CLOCK
LCD_RS
SF_D[11:8]
LCD_RW
LCD_E
Upper
4 bits
LCD_RS
SF_D[11:8]
LCD_RW
LCD_E
1 µs
Figure 5-6: Character LCD Interface Timing
command. The entry mode also determines display shift.
command. However, a display shift is not executed
0 = Command, 1 = Data
Valid Data
40 ns
Lower
4 bits
40 µs
MicroBlaze Development Kit Spartan-3E 1600 Edition User Guide
Set DD RAM Address
Set CG RAM
230 ns
10 ns
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UG257 (v1.1) December 5, 2007
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