Panasonic DP-CL18 Technical Manual page 66

DP-CL18
3.6.11. Control Panel Interface
On the control panel, the LCD (20 character x 2 lines), 6 LEDs and 6 operation keys are located. CPU controls the operations of
LCD, LED through ASIC1 (IC15), IC16, IC17 and detects whether the key is pressed or not through IC16, ASIC1.
The LCD has the LCD control LSI. The signal LCDRS is for selecting the register in the LCD control LSI. When the signal LCDRW
is the low, the data on data bus LCD[7:0] are written in the LCD when the signal LCDEN is the down edge. The LCD displays the
characters.
When the signals LCDRW and LCDEN are the high, the LCD data is outputted to the data bus LCD[7:0] and sent to the CPU
through ASIC1. The CPU reads the LCD data.
The following is the timing chart for writing the LED turning on/off data into the IC3301. Each signals LCD [7:0] is fetched when the
signal LEDSET raises. The LED is turned on or off by the status of each fetched signals [7:0].
The following is the timing chart for reading the key status data. When the signal KEYRD is the low, the key data is outputted on
the data bus LCD [7:0]. The CPU reads this key data through ASIC1 & IC16, and detects whether the keys are pressed or not.
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