Datasheet

9
Electrical Description
Pin Function Description
RESET (RST, Pin 5) Reset initializes the display.
FLASH (FL, Pin 27) FL low indicates an access to the Flash RAM and is unaffected by the
state of address lines A
3
-A
4
.
ADDRESS INPUTS Each location in memory has a distinct address. Address inputs (A
0
-A
2
)
(A
0
-A
4
, Pins 28-32) select a specific location in the Character RAM, the Flash RAM or a
particular row in the UDC (User-Defined Character) RAM. A
3
-A
4
are used to
select which section of memory is accessed. Table 1 shows the logic levels
needed to access each section of memory.
Table 1. Logic Levels to Access Memory
FL A
4
A
3
Section of Memory A
2
A
1
A
0
0 X X Flash RAM Character Address
1 0 0 UDC Address Register Don't Care
1 0 1 UDC RAM Row Address
1 1 0 Control Word Register Don't Care
1 1 1 Character RAM Character Address
CLOCK SELECT This input is used to select either an internal (CLS = 1) or external
(CLS, Pin 1) (CLS = 0) clock source.
CLOCK INPUT/OUTPUT Outputs the master clock (CLS = 1) or inputs a clock (CLS = 0) for slave
(CLK, Pin 2) displays.
WRITE (WR, Pin 3) Data is written into the display when the WR input is low and the CE input
is low.
CHIP ENABLE (CE, Pin 4) This input must be at a logic low to read or write data to the display and
must go high between each read and write cycle.
READ (RD, Pin 6) Data is read from the display when the RD input is low and the CE
input is low.
DATA Bus (D
0
-D
7
, The Data bus is used to read from or write to the display.
Pins 11-14, 19-22)
GND
(SUPPLY)
(Pin 17) This is the analog ground for the LED drivers.
GND
(LOGIC)
(Pin 18) This is the digital ground for internal logic.
V
DD(POWER)
(Pin 16) This is the positive power supply input.