Epson E0C6001 Technical Manual page 133

E0C6001 TECHNICAL SOFTWARE
• I/O Port
• LCD Driver
• Heavy Load Protec-
tion Function
II-52
– When the I/O port is set to the output mode and a low-
impedance load is connected to the port pin, the data
written to the register may differ from the data read.
– When the I/O port is set to the input mode and a low-
level voltage (V
SS
resistance, an erroneous input results if the time con-
stant of the capacitive load of the input line and the built-
in pull-down resistance load is greater than the read-out
time. When the input data is being read, the time that the
input line is pulled down is equivalent to 0.5 cycles of the
CPU system clock.
Hence, the electric potential of the pins must settle within
0.5 cycles. If this condition cannot be met, some measure
must be devised, such as arranging a pull-down resis-
tance externally, or performing multiple read-outs.
– Because the display memory is for writing only, re-writing
the contents with computing instructions (e.g., AND, OR,
etc.) which come with read-out operations is not possible.
To perform bit operations, a buffer to hold the display
data is required on the RAM.
– Even when 1/2 duty is selected, the display data corre-
sponding to COM0, COM3 are valid for static drive.
Hence, for static drive set the same value to all display
memory corresponding COM0–COM3.
– Even when 1/3 duty is selected, the display data corre-
sponding to COM3 is valid for static drive. Hence, for
static drive set the same value to all display memory
corresponding COM0–COM3.
– For cadence adjustment, set the display data including
display data corresponding to COM3.
– fosc indicates the oscillation frequency of the oscillation
circuit.
In the heavy load protection function (heavy load protec-
tion mode flag = "1"), the internal regulated voltage is
more stabler but spend more power current consump-
tion.
) is input by the built-in pull-down