
U
LTRA
C
HIP
High-Voltage Mixed-Signal IC
1999-2002
20
Revision 0.52
D
ISPLAY
D
ATA
RAM
D
ATA
O
RGANIZATION
The display data is 1-bit per pixel and stored in a
dual port static RAM (RAM, for Display Data RAM).
The RAM size is 128x240 for UC1608. This array
of data bits is further organized into pages of 8 bit
slices to facilitate parallel bus interface.
When Mirror X (MX, LC[2]) is OFF, the 1
st
column
of LCD pixels will correspond to the bits of the first
byte of each page, the 2
column of LCD pixels
correspond to the bits of the second byte of each
page, etc.
MSB F
IRST OR
LSB F
IRST
There are two options to map D[7:0] to RAM, MSB
first (MSF=1), or LSB first (MSF=0), as illustrated in
next page.
D
ISPLAY
D
ATA
RAM A
CCESS
The memory used in UC1608 Display Data RAM
(RAM) is a special purpose dual port RAM which
allows asynchronous access to both its column and
row data. Thus, RAM can be independently
accessed both for Host Interface and for display
operations.
D
ISPLAY
D
ATA
RAM A
DDRESSING
A Host Interface (HI) memory access operation
starts with specifying Page Address (PA) and
Column Address (CA) by issuing
Set Page Address
and
Set Column Address
commands.
If wrap-around (WA, AC[0]) is OFF (0), CA will stop
increasing after reaching the end of page (239),
and system programmers need to set the values of
PA and CA explicitly.
If WA is ON (1), when CA reaches end of page, CA
will be reset to 0 and PA will increment or
decrement, depending on the setting of Page
Increment Direction (PID, AC[2]). When PA
reaches the boundary of RAM (i.e. PA = 0 or 19),
PA will be wrapped around to the other end of RAM
and continue.