RAiO RA8835A - RAiO Technology Inc.

RAiO
RA8835A
Dot Matrix
LCD Controller
Specification
Version 1.3
June 06, 2008
RAiO Technology Inc.
©Copyright RAiO Technology Inc. 2006, 2007, 2008
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Update History
Version
Date
0.9
1.0
February 7, 2007
1.1
December 17, 2007
Description
Preliminary version
First Release
Update Section 10-3-3 Display Memory Read Timing, the clock
period of “EXT Φ0”.
Update Section 7-8 “Reset” – The minimum timing requirement
1.2
January 16, 2008
1.3
June 6, 2008
RAiO TECHNOLOGY INC.
for the following the rising edges of both RES and VDD to allow
for system stabilization.
Note: The specification of this version is for RA8835AP3N and
RA8835AP4N.
Update Section 10-3-7 “LCD Output Timing” and Parameters
2/88
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RA8835A
Version 1.3
Chapter
Dot Matrix LCD Controller
Contents
Pages
1. Overview .........................................................................................................6
2. Features ..........................................................................................................6
3. Block Diagram................................................................................................6
4. Package ..........................................................................................................7
5. Pin Descriptions.............................................................................................7
5-1 Pin Functions ................................................................................................................7
5-1-1 MCU Interface .......................................................................................................................................7
5-1-2 Display Memory Control ......................................................................................................................8
5-1-3 LCD Drive Signals ................................................................................................................................9
5-1-4 Oscillator and Power............................................................................................................................9
5-2 RA8835A Pin Summary...............................................................................................10
6. Instruction Set..............................................................................................11
6-1 The Command Set.......................................................................................................11
6-2 System Control Commands .......................................................................................12
6-2-1 SYSTEM SET...................................................................................................................................... 12
6-2-2 SLEEP IN ............................................................................................................................................ 20
6-3 Display Control Commands .......................................................................................21
6-3-1 DISP ON/OFF...................................................................................................................................... 21
6-3-2 SCROLL.............................................................................................................................................. 23
6-3-3 CSRFORM .......................................................................................................................................... 27
6-3-4 CSRDIR............................................................................................................................................... 28
6-3-5 OVLAY ................................................................................................................................................ 29
6-3-6 CGRAM ADR ...................................................................................................................................... 30
6-3-7 HDOT SCR.......................................................................................................................................... 31
6-4 Drawing Control Commands......................................................................................32
6-4-1 CSRW.................................................................................................................................................. 32
6-4-2 CSRR .................................................................................................................................................. 32
6-5 Memory Control Commands ......................................................................................33
6-5-1 MWRITE .............................................................................................................................................. 33
6-5-2 MREAD ............................................................................................................................................... 33
7. Functions Description .................................................................................34
7-1 MCU Bus Interface ......................................................................................................34
7-1-1 8080 Series......................................................................................................................................... 34
7-1-2 6800 Series......................................................................................................................................... 34
7-2 MCU Synchronization .................................................................................................34
7-2-1 Display Status Indication Output..................................................................................................... 34
7-2-2 Internal Register Access .................................................................................................................. 35
7-2-3 Display Memory Access ................................................................................................................... 35
7-3 MCU Interface Examples ............................................................................................36
7-3-1 Z80 to RA8835A Interface ................................................................................................................. 36
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-3-2 6802 to RA8835A Interface ............................................................................................................... 36
7-4 Static RAM ...................................................................................................................37
7-5 Supply Current during Display Memory Access ......................................................37
7-6 Oscillator Circuit .........................................................................................................38
7-7 Status Flag...................................................................................................................38
7-8 Reset ............................................................................................................................40
7-9 Character Configuration.............................................................................................40
7-10 Screen Configuration................................................................................................41
7-10-1 Screen Configuration...................................................................................................................... 41
7-10-2 Display Address Scanning ............................................................................................................. 42
7-10-3 Display Scan Timing ....................................................................................................................... 44
7-11 Cursor Control...........................................................................................................45
7-11-1 Cursor Register Function ............................................................................................................... 45
7-11-2 Cursor Movement ............................................................................................................................ 45
7-11-3 Cursor Display Layers .................................................................................................................... 45
7-12 Memory to Display Relationship..............................................................................47
7-13 Scrolling.....................................................................................................................50
7-13-1 On-page Scrolling ........................................................................................................................... 50
7-13-2 Inter-page Scrolling......................................................................................................................... 50
7-13-3 Horizontal Scrolling ........................................................................................................................ 51
7-13-4 Bi-directional Scrolling ................................................................................................................... 51
7-13-5 Scroll Units....................................................................................................................................... 52
7-14 CG Characteristics....................................................................................................52
7-14-1 Internal Character Generator ......................................................................................................... 52
7-14-2 External Character Generator ROM............................................................................................... 52
7-14-3 Character Generator RAM .............................................................................................................. 52
7-15 CG Memory Allocation..............................................................................................53
7-16 Setting Character Generator Address.....................................................................54
7-16-1 M1 = 1................................................................................................................................................ 54
7-16-2 CG RAM Addressing Example ....................................................................................................... 55
7-17 Character Codes .......................................................................................................56
8. Application Notes ........................................................................................57
8-1 Initialization Parameters.............................................................................................57
8-1-1 System Set Instruction and Parameters ......................................................................................... 57
8-1-2 Initialization Example........................................................................................................................ 59
8-1-3 Display Mode Setting Example 1: combining text and graphics.................................................. 64
8-1-4 Display Mode Setting Example 2: combining graphics and graphics ......................................... 65
8-1-5 Display Mode Setting Example 3: combining three graphics layers ........................................... 66
8-2 System Overview ........................................................................................................68
8-3 System Interconnection .............................................................................................69
8-4 Smooth Horizontal Scrolling ......................................................................................71
8-5 Layered Display Attributes.........................................................................................72
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-5-1 Inverse Display .................................................................................................................................. 72
8-5-2 Half-tone Display ............................................................................................................................... 73
8-5-3 Flashing Area..................................................................................................................................... 73
8-6 16 x 16-dot Graphic Display .......................................................................................74
8-6-1 Command Usage ............................................................................................................................... 74
8-6-2 Kanji Character Display .................................................................................................................... 74
8-7 Internal Character Generator Font.............................................................................76
9. Package Dimensions ...................................................................................77
10. Specifications.............................................................................................78
10-1 Absolute Maximum Ratings .....................................................................................78
10-2 DC Characteristic ......................................................................................................79
10-3 Timing Diagrams .......................................................................................................81
10-3-1 8080 Family Interface Timing ......................................................................................................... 81
10-3-2 6800 Family Interface Timing ......................................................................................................... 82
10-3-3 Display Memory Read Timing ........................................................................................................ 83
10.3-4 Display Memory Write Timing ........................................................................................................ 84
10-3-5 Sleep In Command Timing ............................................................................................................. 85
10-3-6 External Oscillator Signal Timing .................................................................................................. 86
10-3-7 LCD Output Timing ......................................................................................................................... 87
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RA8835A
Version 1.3
Dot Matrix LCD Controller
1. Overview
The RA8835A is a controller IC that can display text and graphics on LCD panel. It can display layered text
and graphics, scroll the display in any direction and partition the display into multiple screens. It also stores
text, character codes and bitmapped graphics data in external frame buffer memory. Display controller
functions include transferring data from the controlling microprocessor to the buffer memory, reading
memory data, converting data to display pixels and generating timing signals for the buffer memory, LCD
panel.
The RA8835A has an internal character generator with 160, 5x7 pixel characters in internal mask ROM. The
character generators support up to 64, 8x16 pixel characters in external character generator RAM and up to
256, 8x16 pixel characters in external character generator ROM.
2. Features
‹
‹
‹
‹
‹
‹
‹
‹
Text, graphics and combined text/graphics
display modes
Three overlapping screens in graphics
mode
Up to 640x256 pixel LCD panel display
resolution
Programmable cursor control
Smooth horizontal and vertical scrolling of
all or part of the display
1/2-duty to 1/256-duty LCD drive
Up to 640x256 pixel LCD panel display
resolution memory
160, 5x7 pixel characters in internal maskprogrammed character generator ROM
‹
‹
‹
‹
‹
‹
Up to 64, 8x16 pixel characters in external
character generator RAM
Up to 256, 8x16 pixel characters in external
character generator ROM
6800 and 8080 family microprocessor
interfaces
Low power consumption: 3.5mA operating
current (VDD = 3.5V), 0.05μA standby
current
Package(ROHS Compliance):
RA8835AP3N: QFP-60 pin
RA8835AP4N: TQFP-60 pin
Power: 2.7 to 5.5 V
3. Block Diagram
V A [1 5 :0 ], V D [7 :0 ],
TE S T
V C E , V R D , V W R
2 5 6 B y te
C G R O M
D is p la y R A M
I/F
S y s te m
C o n fig u r e
R e g is te r s
B lo c k
C u rs o r
C o n t r o lle r
D a ta
L a tc h
M C U
I/F
X ’ta l
O S C
T im in g
G e n e ra to r
D [7 :0 ], C S , R D , W R
X D
A 0, R E S , S E L1, S E L2
X G
Y D IS , L P , W F , X S C L ,
Y D , Y S C L , X D [3 :0 ]
Figure 3-1: Block Diagram
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RA8835A
Version 1.3
Dot Matrix LCD Controller
XG
SEL1
SEL2
WR
RD
NC
NC
RES
VRD
VCE
VWR
VA0
VA1
VA2
VA3
VA4
VA5
VA6
VA7
VD4
VD5
VD6
VD7
YSCL
YD
YDIS
WF
LP
GND
XSCL
SECL
XD0
XD1
XD2
4. Package
45
XD
CS
A0
VDD
D0
D1
D2
D3
D4
D5
D6
50
45
RAiO
40
35
TM
30
60
RA8835AP3N
1
29
07xx
Index
25
Date Code(Year 2007)
5
10
15
20
NC
VA14
VA15
VD0
VD1
VD2
VD3
VD2
VD1
VD0
VA15
VA14
VA13
VA12
VA11
VA10
VA9
VA8
VA7
VA6
NC
31
30
46
RAiO
XD3
D7
D6
D5
D4
D3
D2
D1
D0
VDD
A0
CS
XD
XG
SEL1
TM
RA8835AP4N
07xx
Index
60
Date Code(Year 2007)
16
15
1
VA5
VA4
VA3
VA2
VA1
VA0
VWR
VCE
VRD
RES
NC
NC
RD
WR
SEL2
D7
XD3
XD2
XD1
XD0
XECL
XSCL
GND
LP
WF
YDIS
YD
YSCL
VD7
VD6
VD5
VD4
VD3
6
VA8
VA9
VA10
VA11
VA12
VA13
Figure 4-1: RA8835AP3N(QFP-60 Pin)
Figure 4-2: RA8835AP4N (TQFP-60 Pin)
5. Pin Descriptions
5-1 Pin Functions
5-1-1 MCU Interface
Pin
Name
D0 to D7
Function
MCU Data Bus.
Tristate input/output pins. Connect these pins to an 8- or 16-bit microprocessor bus.
MCU Interface Select.
The RA8835A series supports both 8080 family processors (such as the 8085 and
Z80®) and 6800 family processors (such as the 6802 and 6809).
SEL1,
SEL2
SEL1
SEL2*
Interface
A0
RD
WR
CS
0
0
8080 family
A0
RD
WR
CS
1
0
6800 family
A0
E
R/ W
CS
SEL1 should be tied directly to VDD or VSS to prevent noise. If noise does appear on
SEL1, decouple it to ground using a capacitor placed as close to the pin as possible.
RD
or
E
Read Control or Enable.
When the 8080 family interface is selected, this signal acts as the active-LOW read
strobe. The RA8835A series output buffers are enabled when this signal is active.
When the 6800 family interface is selected, this signal acts as the active-HIGH
enable clock.
Data is read from or written to the RA8835A series when this clock goes HIGH.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
WR
or
R/ W
CS
Write Control or Read/Write Control.
When the 8080 family interface is selected, this signal acts as the active-LOW write
strobe. The bus data is latched on the rising edge of this signal.
When the 6800 family interface is selected, this signal acts as the read/write control
signal. Data is read from the RA8835A series if this signal is HIGH, and written to the
RA8835A series if it is LOW.
Chip Select.
This active-LOW input enables the RA8835A series. It is usually connected to the
output of an address decoder device that maps the RA8835A series into the memory
space of the controlling microprocessor.
Command/Data Select.
8080 Family Interface:
A0
0
1
0
1
A0
RD
0
0
1
1
WR
1
1
0
0
Function
Status flag read
Display data and cursor address read
Display data and parameter write
Command write
E
1
1
1
1
Function
Status flag read
Display data and cursor address read
Display data and parameter write
Command write
6800 Family Interface:
A0
0
1
0
1
RES
R/ W
1
1
0
0
Hardware Reset.
This active-LOW input performs a hardware reset on the RA8835A series. It is an
Schmitt-trigger input for enhanced noise immunity; however, care should be taken to
ensure that it is not triggered if the supply voltage is lowered.
5-1-2 Display Memory Control
The RA8835A series can directly access static RAM and PROM. The designer may use a mixture of
these two types of memory to achieve an optimum trade-off between low cost and low power
consumption.
Pin
Name
VA0 to
VA15
VD0 to
VD7
VWR
VRD
VCE
Function
16-bit Display Memory Address.
When accessing character generator RAM or ROM, VA0 to VA3, reflect the lower 4
bits of the RA8835A series’ row counter.
Display Memory Data Bus.
8-bit tristate display memory data bus. These pins are enabled when VR/ W is LOW.
Display Memory Write Control.
Active-LOW display memory write control output.
Display Memory Read Control.
Active-LOW display memory read control output.
Display Memory Chip Select.
Active-LOW static memory standby control signal. VCE can be used with CS .
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RA8835A
Version 1.3
Dot Matrix LCD Controller
5-1-3 LCD Drive Signals
In order to provide effective low-power drive for LCD matrixes, the RA8835A series can directly
control both the X- and Y-drivers using an enable chain.
Pin
Name
XD0 to
XD3
XSCL
XECL
LP
WF
YSCL
YD
YDIS
Function
Data Output for Driver.
4-bit X-driver (column drive) data outputs. Connect these outputs to the inputs of the
X-driver chips.
Latch Clock.
The falling edge of XSCL latches the data on XD0 to XD3 into the input shift registers
of the X-drivers. To conserve power, this clock halts between LP and the start of the
following display line (See Section 10-3-7).
Trigger Clock for Chain Cascade.
The falling edge of XECL triggers the enable chain cascade for the X-drivers. Every
16th clock pulse is output to the next X-driver.
Latch Pulse.
LP latches the signal in the X-driver shift registers into the output data latches. LP is a
falling-edge triggered signal, and pulses once every display line.
Connect LP to the Y-driver shift clock on modules.
AC Drive Output.
The WF period is selected to be one of two values with SYSTEM SET command.
Latch Clock for YD.
The falling edge of YSCL latches the data on YD into the input shift registers of the Ydrivers. YSCL is not used with driver ICs that use LP as the Y-driver shift clock.
Data Pulse Output for Y Drivers.
It is active during the last line of each frame, and is shifted through the Y drivers one
by one (by YSCL), to scan the display’s common connections.
Power-down Output Signal.
YDIS is HIGH while the display drive outputs are active. YDIS goes LOW one or two
frames after the sleep command is written to the RA8835A series. All Y-driver outputs
are forced to an intermediate level (de-selecting the display segments) to blank the
display. In order to implement power-down operation in the LCD unit, the LCD power
drive supplies must also be disabled when the display is disabled by YDIS.
5-1-4 Oscillator and Power
Pin
Name
Function
Crystal Connection for Internal Oscillator
This pin can be driven by an external clock source that satisfies the timing
specifications of the EXT f0 signal (See Section 10-3-6).
Crystal Connection for Internal Oscillator
XD
Leave this pin open when using an external clock source.
2.7 to 5.5V Supply.
VDD
This may be the same supply as the controlling microprocessor.
GND
Ground
Note: The peak supply current drawn by the RA8835A series may be up to ten times the average
supply current. The power supply impedance must be kept as low as possible by ensuring
that supply lines are sufficiently wide and by placing 0.47μF decoupling capacitors that have
good high-frequency response near the device’s supply pins.
XG
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RA8835A
Version 1.3
Dot Matrix LCD Controller
5-2 RA8835A Pin Summary
Name
Number
Type
Description
RA8835AP3N
RA8835AP4N
VA0 to
VA15
27 to 28
30 to 43
1 to 6
50 to 59
Output
VRAM address bus
VWR
44
7
Output
VRAM write signal
VCE
45
8
Output
Memory control signal
VRD
46
9
Output
VRAM read signal
RES
NC
47
28, 48, 49
10
11, 12, 60
Input
—
Reset
No connection
RD
50
13
Input
8080 family: Read signal 6800 family:
Enable clock (E)
WR
51
14
Input
8080 family: Write signal
6800 family: R/ W signal
SEL2
SEL1
XG
XD
CS
A0
VDD
52
53
54
55
15
16
17
18
19
20
21
Input
Input
Input
Output
Input
Input
Supply
22 to 29
Input/output
7 to 10
30 to 33
Output
X-driver data
11
12
13
14
15
34
35
36
37
38
Output
Output
Supply
Output
Output
YDIS
16
39
Output
YD
YSCL
VD0 to
VD7
17
18
40
41
Output
Output
X-driver enable chain clock
X-driver data shift clock
Ground
Latch pulse
Frame signal
Power-down signal when display is
blanked
Scan start pulse
Y-driver shift clock
19 to 26
42 to 49
Input/output
D0 to D7
56
57
58
59 to 60
1 to 6
XD0 to
XD3
XECL
XSCL
VSS
LP
WF
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8080 or 6800 family interface select
8080 or 6800 family interface select
Oscillator connection
Oscillator connection
Chip select
Data type select
2.7 to 5.5V supply
Data bus
VRAM data bus
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6. Instruction Set
6-1 The Command Set
Table-1: Command Set
Command
Code
Class
Command
Hex
Command
Description
RD WR A0 D7 D6 D5 D4 D3 D2 D1 D0
System
Control
SYSTEM
SET
SLEEP IN
DISPLAY
ON/OFF
0
1
0
1
0
0
0
0
0
0
40
1
0
1
0
1
0
1
0
0
1
1
53
0
1
0
1
0
1
1
0
0
D
No. of
Bytes
1
1
Read
Parameters
58,
59
Initialize device and
display
Enter standby mode
Section
8
9-2-1
0
9-2-2
1
9-3-1
10
9-3-2
2
9-3-3
2
9-3-6
0
9-3-4
1
9-3-7
1
9-3-5
Enable and disable
display and display
flashing
Set display start
SCROLL
1
0
1
0
1
0
0
0
1
0
0
44
address and display
regions
CSRFORM
Display
CGRAM
Control
ADR
CSRDIR
1
0
1
0
1
0
1
1
1
0
1
5D
Set cursor type
Set start address of
1
0
1
0
1
0
1
1
1
0
0
5C
character generator
RAM
1
0
1
0
1
0
0
1
1
CD CD
1
0
4C
to
4F
HDOT SCR
1
0
1
0
1
0
1
1
0
1
0
5A
OVLAY
1
0
1
0
1
0
1
1
0
1
1
5B
Set direction of cursor
movement
Set horizontal scroll
position
Set display overlay
format
Drawing
CSRW
1
0
1
0
1
0
0
0
1
1
0
46
Set cursor address
2
9-r1
Control
CSRR
1
0
1
0
1
0
0
0
1
1
1
47
Read cursor address
2
9-4-2
MWRITE
1
0
1
0
1
0
0
0
0
1
0
42
—
9-5-1
MREAD
1
0
1
0
1
0
0
0
0
1
1
43
—
9-5-2
Memory
Control
Write to display
memory
Read from display
memory
Notes:
1. In general, the internal registers of the RA8835A series are modified as each command parameter is
input. However, the microprocessor does not have to set all the parameters of a command and may
send a new command before all parameters have been input. The internal registers for the
parameters that have been input will have been changed but the remaining parameter registers are
unchanged. 2-byte parameters (where two bytes are treated as 1 data item) are handled as follows:
a. CSRW, CSRR: Each byte is processed individually. The microprocessor may read or write
just the low byte of the cursor address.
b. SYSTEM SET, SCROLL, CGRAM ADR: Both parameter bytes are processed together. If
the command is changed after half of the parameter has been input, the single byte is
ignored.
2. APL and APH are 2-byte parameters, but are treated as two 1-byte parameters.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2 System Control Commands
6-2-1 SYSTEM SET
Initializes the device, sets the window sizes, and selects the LCD interface format. Since this
command sets the basic operating parameters of the RA8835A series, an incorrect SYSTEM SET
command may cause other commands to operate incorrectly.
MSB
LSB
D7 D6
D5 D4 D3
C
0
1
0
0
P1
0
0
IV
P2
WF
0
P3
0
0
0
D2 D1
0
0
1
1 W/S M2 M1 M0
0
0
1
0
0
0
0
1
0
0
0
0
1
FX
FY
0
A0 WR RD
1
0
0
D0
P4
C/R
0
0
1
P5
TC/R
0
0
1
P6
L/F
0
0
1
P7
APL
0
0
1
P8
APH
0
0
1
Figure 6-1: SYSTEM SET Instruction
6-2-1-1 C
This control byte performs the following:
1. Resets the internal timing generator
2. Disables the display
3. Cancels sleep mode
Parameters following P1 are not needed if only canceling sleep mode.
6-2-1-2 M0
Select the internal or external character generator ROM. The internal character generator ROM
contains 160, 5 X 7 pixel characters, as shown in Figure 8-14. These characters are fixed at
fabrication by the metallization mask.
The external character generator ROM, on the other hand, can contain up to 256 user-defined
characters.
M0 = 0: Internal CG ROM
M0 = 1: External CG ROM
Note that if the CG ROM address space overlaps the display memory address space, that portion
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RA8835A
Version 1.3
Dot Matrix LCD Controller
of the display memory cannot be written to.
6-2-1-3 M1
Select the memory configuration for user-definable characters. The CG RAM codes select one of
the 64 codes shown in figure 7-29.
M1 = 0: No D6 correction.
The CG RAM1 and CG RAM2 address spaces are not contiguous, the CG RAM1 address space is
treated as character generator RAM, and the CG RAM2 address space is treated as character
generator ROM.
M1 = 1: D6 correction.
The CG RAM1 and CG RAM2 address spaces are contiguous and are both treated as character
generator RAM.
6-2-1-4 M2
Select the height of the character bitmaps. Characters more than 16 pixels high can be displayed
by creating a bitmap for each portion of each character and using the RA8835A series graphics
mode to reposition them.
M2 = 0: 8-pixel character height (2716 or equivalent ROM)
M2 = 1: 16-pixel character height (2732 or equivalent ROM)
6-2-1-5 W/S
Select the LCD drive method.
W/S = 0: Single-panel drive
W/S = 1: Dual-panel drive
EI
X
driver
X
driver
YD
Y
driver
LCD
Figure 6-2: Single-panel Display
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RA8835A
Version 1.3
Dot Matrix LCD Controller
EI
X
driver
X
driver
YD
Upper
Panel
Y
driver
Lower
Panel
X
driver
X
driver
Figure 6-3: Above and Below Two-panel Display
EI
X driver
X driver
X driver
X driver
YD
Y driver
Left Panel
Right Panel
Figure 6-4: Left-and-Right Two-panel Display
Note: There are no RAiO LCD units in the configuration shown in Figure 6-4.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-2: LCD Parameters
Parameter
W/S = 0
W/S = 1
IV = 1
IV = 0
IV = 1
IV = 0
C/R
TC/R
C/R
TC/R
C/R
TC/R (See note 1.)
C/R
TC/R
C/R
TC/R
L/F
L/F
L/F
L/F
SL1
00H to L/F
(L/F) / 2
(L/F) / 2
SL2
00H to L/F
L/F
00H to L/F + 1
(See note 2.)
00H to L/F + 1
(See note 2.)
First screen block
Second screen
block
Third screen block
(L/F) / 2
(L/F) / 2
SAD1
SAD2
SAD3
SAD4
Cursor
movement
range
First screen block
Second screen
block
Third screen block
Invalid
Invalid
Continuous movement over whole screen
First screen block
Second screen
block
Third screen block
First screen block
Second screen
block
Third screen block
Fourth screen block
Fourth screen block
Above-and-below configuration:
continuous movement over whole screen
Notes:
1. See Table-24 for further details on setting the C/R and TC/R parameters when using
2. The value of SL when IV = 0 is equal to the value of SL when IV = 1, plus one.
6-2-1-6 IV
Screen origin compensation for inverse display. IV is usually set to 1. The best way of displaying
inverted characters is to Exclusive-OR the text layer with the graphics background layer. However,
inverted characters at the top or left of the screen are difficult to read as the character origin is at
the top-left of its bitmap and there are no background pixels either above or to the left of these
characters.
The IV flag causes the RA8835A series to offset the text screen against the graphics back layer by
one vertical pixel. Use the horizontal pixel scroll function (HDOT SCR) to shift the text screen 1 to
7 pixels to the right. All characters will then have the necessary surrounding background pixels that
ensure easy reading of the inverted characters. See Section 7-13 for information on scrolling.
IV = 0: Screen top-line correction
IV = 1: No screen top-line correction
Display start point
IV
HDOT SCR
Character
Dots 1 to 7
Figure 6-5: IV and HDOT SCR Adjustment
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2-1-7 FX
Define the horizontal character size. The character width in pixels is equal to FX + 1, where FX can
range from 00 to 07H inclusive. If data bit 3 is set (FX is in the range 08 to 0FH) and an 8-pixel font
is used, a space is inserted between characters.
Table-3: Horizontal Character Size Selection
FX
[FX] character
D
D
D
D
width (pixels)
HEX
3
2
1
0
00
0
0
0
0
1
01
0
0
0
1
2
↓
↓
↓
↓
↓
↓
07
0
1
1
1
8
Since the RA8835A series handles display data in 8-bit units, characters larger than 8 pixels wide
must be formed from 8-pixel segments. As Figure 6-6 shows, the remainder of the second eight
bits are not displayed. This also applies to the second screen layer.
In graphics mode, the normal character field is also eight pixels. If a wider character field is used,
any remainder in the second eight bits is not displayed.
FX
FY
FX
8 bits
FY
8 bits
8 bits
8 bits
Non-display area
Address A
Address B
Figure 6-6: FX and FY Display Addresses
6-2-1-8 WF
Select the AC frame drive waveform period. WF is usually set to 1.
WF = 0: 16-line AC drive
WF = 1: two-frame AC drive
In two-frame AC drive, the WF period is twice the frame period.
In 16-line AC drive, WF inverts every 16 lines.
Although 16-line AC drive gives a more readable display, horizontal lines may appear when using
high LCD drive voltages or at high viewing angles.
RAiO TECHNOLOGY INC.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2-1-9 FY
Set the vertical character size. The height in pixels is equal to FY + 1. FY can range from 00 to
0FH inclusive. Set FY to zero (vertical size equals one) when in graphics mode.
Table-4: Vertical Character Size Selection
FY
[FY] character
D
D
D
D
height
(pixels)
HEX
3
2
1
0
00
0
0
0
0
1
01
0
0
0
1
2
↓
↓
↓
↓
↓
↓
07
0
1
1
1
8
↓
↓
↓
↓
↓
↓
0E
1
1
1
0
15
0F
1
1
1
1
16
6-2-1-10 C/R
Set the address range covered by one display line, that is, the number of characters less one,
multiplied by the number of horizontal bytes per character. C/R can range from 0 to 239.
For example, if the character width is 10 pixels, then the address range is equal to twice the
number of characters, less 2. See Section 8-1-1 for the calculation of C/R. [C/R] cannot be set to a
value greater than the address range. It can, however, be set smaller than the address range, in
which case the excess display area is blank. The number of excess pixels must not exceed 64.
HEX
00
01
↓
4F
↓
EE
EF
D7
0
0
↓
0
↓
1
1
RAiO TECHNOLOGY INC.
D6
0
0
↓
1
↓
1
1
Table-5: Display Line Address Range
C/R
[C/R] bytes per display line
D5 D4 D3 D2 D1 D0
0
0
0
0
0
0
1
0
0
0
0
0
1
2
↓
↓
↓
↓
↓
↓
↓
0
0
1
1
1
1
80
↓
↓
↓
↓
↓
↓
↓
1
0
1
1
1
0
239
1
0
1
1
1
1
240
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2-1-11 TC/R
Set the length, including horizontal blanking, of one line. The line length is equal to TC/R + 1,
where TC/ R can range from 0 to 255. TC/R must be greater than or equal to C/R + 4. Provided
this condition is satisfied, [TC/R] can be set according to the equation given in Section 8-1-1 in
order to hold the frame period constant and minimize jitter for any given main oscillator frequency,
fOSC.
HEX
00
01
↓
52
↓
FE
FF
D7
0
0
↓
0
↓
1
1
D6
0
0
↓
1
↓
1
1
D5
0
0
↓
0
↓
1
1
Table-6: Line Length Selection
TC/R
[TC/R] line length (bytes)
D4 D3 D2 D1 D0
0
0
0
0
0
1
0
0
0
0
1
2
↓
↓
↓
↓
↓
↓
1
0
0
1
0
83
↓
↓
↓
↓
↓
↓
1
1
1
1
0
255
1
1
1
1
1
256
6-2-1-12 L/F
Set the height, in lines, of a frame. The height in lines is equal to L/F + 1, where L/F can range
from 0 to 255.
Table-7: Frame Height Selection
L/F
[L/F] lines per frame
HEX D7 D6 D5 D4 D3 D2 D1 D0
00
0
0
0
0
0
0
0
0
1
01
0
0
0
0
0
0
0
1
2
↓
↓
↓
↓
↓
↓
↓
↓
↓
↓
7F
0
1
1
1
1
1
1
1
128
↓
↓
↓
↓
↓
↓
↓
↓
↓
↓
FE
1
1
1
1
1
1
1
0
255
FF
1
1
1
1
1
1
1
1
256
If W/S is set to 1, selecting two-screen display, the number of lines must be even and L/F must,
therefore, be an odd number.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2-1-13 AP
Define the horizontal address range of the virtual screen. APL is the least significant byte of the
address.
Figure 6-7: AP Parameters
Table-8: Horizontal Address Range
Hex code
[AP] addresses
per line
APH
APL
0
0
0
0
0
0
0
0
1
1
↓
↓
↓
↓
↓
0
0
5
0
80
↓
↓
↓
↓
↓
F
F
F
E
216– 2
F
F
F
F
216– 1
Display area
C/R
Display memory limit
AP
Figure 6-8: AP and C/R Relationship
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-2-2 SLEEP IN
Place the system in standby mode. This command has no parameter bytes. At least one blank
frame after receiving this command, the RA8835A halts all internal operations, including the
oscillator, and enters the sleep state.
Blank data is sent to the X-drivers, and the Y-drivers have their bias supplies turned off by the
YDIS signal. Using the YDIS signal to disable the Y-drivers guards against any spurious displays.
The internal registers of the RA8835A series maintain their values during the sleep state. The
display memory control pins maintain their logic levels to ensure that the display memory is not
corrupted. The RA8835A series can be removed from the sleep state by sending the SYSTEM
SET command with only the P1 parameter. The DISP ON command should be sent next to enable
the display.
Figure 6-9: SLEEP IN Instruction
1. The YDIS signal goes LOW between one and two frames after the SLEEP IN command is
received. Since YDIS forces all display driver outputs to go to the deselected output voltage,
YDIS can be used as a power-down signal for the LCD unit. This can be done by having YDIS
turn off the relatively high power LCD drive supplies at the same time as it blanks the display.
2. Since all internal clocks in the RA8835A series are halted while in the sleep state, a DC voltage
will be applied to the LCD panel if the LCD drive supplies remain on. If reliability is a prime
consideration, turn off the LCD drive supplies before issuing the SLEEP IN command.
3. Note that, although the bus lines become high impedance in the sleep state, pull-up or pulldown resistors on the bus will force these lines to a known state.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3 Display Control Commands
6-3-1 DISP ON/OFF
Turn the whole display on or off. The single-byte parameter enables and disables the cursor and
layered screens, and sets the cursor and screen flash rates. The cursor can be set to flash over
one character or over a whole line.
MSB
LSB
C
0
1
0
1
1
0
0
D
P1
FP5
FP4
FP3
FP2
FP1
FP0
FC1
FC0
Figure 6-10: DISP ON/OFF Parameters
6-3-1-1 D
Turn the display ON or OFF. The D bit takes precedence over the FP bits in the parameter.
D = 0: Display OFF
D = 1: Display ON
6-3-1-2 FC
Enables/disables the cursor and sets the flash rate. The cursor flashes with a 70% duty cycle
(ON/OFF).
Table-9: Cursor Flash Rate Selection
FC1
FC0
Cursor display
0
0
OFF (blank)
0
1
No flashing
Flash at fFR/32 Hz
1
0
(approx. 2 Hz)
ON
Flash at fFR/64 Hz
1
1
(approx. 1 Hz)
Note: As the MWRITE command always enables the cursor, the cursor position can be checked
even when performing consecutive writes to display memory while the cursor is flashing.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3-1-3 FP
Each pair of bits in FP sets the attributes of one screen block, as follows. The display attributes are
as follows:
Table-10: Screen Block Attribute Selection
FP1
FP0
First screen block (SAD1)
Second screen block
FP3
FP2
(SAD2, SAD4). See note.
FP5
FP4
Third screen block (SAD3)
0
0
OFF (blank)
0
1
No flashing
Flash at fFR/32 Hz
1
0
ON
(approx. 2 Hz)
Flash at fFR/4 Hz
1
1
(approx. 16 Hz)
Note: If SAD4 is enabled by setting W/S to 1, FP3 and FP2 control both SAD2 and SAD4. The
attributes of SAD2 and SAD4 cannot be set independently.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3-2 SCROLL
6-3-2-1 C
Set the scroll start address and the number of lines per scroll block. Parameters P1 to P10 can be
omitted if not required. The parameters must be entered sequentially as shown in Figure 6-11.
M SB
LSB
C
0
1
0
0
0
1
0
0
P1
A7
A6
A5
A4
A3
A2
A1
A0
(SAD 1L)
P2
A15
A14
A13
A12
A11
A10
A9
A8
(SAD 1H )
P3
L7
L6
L5
L4
L3
L2
L1
L0
(SL1)
P4
A7
A6
A5
A4
A3
A2
A1
A0
(SAD 2L)
P5
A15
A14
A13
A12
A11
A10
A9
A8
(SAD 2H )
P6
L7
L6
L5
L4
L3
L2
L1
L0
P7
A7
A6
A5
A4
A3
A2
A1
A0
(SAD 3L)
P8
A15
A14
A13
A12
A11
A10
A9
A8
(SAD 3H )
P9
A7
A6
A5
A4
A3
A2
A1
A0
(SAD 4L)
P10
A15
A14
A13
A12
A11
A10
A9
A8
(SAD 4H )
(SL2)
Figure 6-11: SCROLL Instruction Parameters
Note: Set parameters P9 and P10 only if both two-screen drive (W/S = 1) and two-layer
configuration are selected. SAD4 is the fourth screen block display start address.
HEX
00
01
↓
7F
↓
FE
FF
L7
0
0
↓
0
↓
1
1
RAiO TECHNOLOGY INC.
Table-11: Screen Block Start Address Selection
SL1, SL2
[SL] screen lines
L6
L5
L4
L3
L2
L1
L0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
1
2
↓
↓
↓
↓
↓
↓
↓
↓
1
1
1
1
1
1
1
128
↓
↓
↓
↓
↓
↓
↓
↓
1
1
1
1
1
1
0
255
1
1
1
1
1
1
1
256
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3-2-2 SL1, SL2
SL1 and SL2 set the number of lines per scrolling screen. The number of lines is SL1 or SL2 plus
one. The relationship between SAD, SL and the display mode is described below.
W/S
Table-12: Text Display Mode
Screen
First Layer
Second Layer
First screen block
SAD1
SAD2
Second screen block
SL1
SL2
SAD3 (see note 1)
Third screen block (partitioned screen)
Set both SL1 and SL2 to L/F + 1 if not
using a partitioned screen.
Screen configuration example:
SAD2
0
SL2
SAD1
Graphics display page 2
SL1
Character display page 1
SAD3
Character display page 3
Layer 2
Layer 1
SAD1
SL1
SAD3
Lower screen
(See note 2)
Set both SL1 and SL2 to ((L/F) / 2 + 1)
Screen configuration example:
Upper screen
SAD2
SL2
SAD4
(See note 2)
SAD2
1
SAD1
SL1
Graphics display page 2
Character display page 1
SAD3
Graphics display page 4
Character display page 3
(SAD4)
Layer 1
Layer 2
Notes:
1. SAD3 has the same value as either SAD1 or SAD2, whichever has the least number of
lines (set by SL1 and SL2).
2. Since the parameters corresponding to SL3 and SL4 are fixed by L/F, they do not have to
be set in this mode.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-13: Graphics Display Mode
Screen
First Layer
Second Layer
SAD1
SAD2
Two-layer composition
SL1
SL2
SAD3 (see note 3)
Upper screen
Set both SL1 and SL2 to L/F + 1
if not using a partitioned screen
Screen configuration example:
W/S
Third Layer
—
—
SAD2
SL2
0
SAD1
Graphics display page 2
SL1
Character display page 1
SAD3
Character display page 3
Layer 1
Layer 2
SAD1
SAD2
SL1 = L/F + 1
SL1 = L/F + 1
Screen configuration example:
Three-layer configuration
SAD3
—
SAD3
Graphics display page 3
SAD2
SAD1
SL2
0
Graphics display page 2
SL1
Graphics display page 1
Layer 1
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-13: Graphics Display Mode (continued)
Screen
First Layer
Second Layer
SAD1
SAD2
Upper screen
SL1
SL2
SAD3
SAD4
Lower screen
(See note 2)
(See note 2)
Screen configuration example (See note 3):
W/S
Third Layer
—
—
SAD2
1
SAD1
SL1
Graphics display page 2
Graphics display page 1
SAD3
Graphics display page 4
Graphics display page 3
Layer 1
Layer 2
Notes:
1. SAD3 has the same value as either SAD1 or SAD2; whichever has the least number of
lines (set by SL1 and SL2).
2. Since the parameters corresponding to SL3 and SL4 are fixed by L/F, they do not have to
be set.
3. If, and only if, W/S = 1, the differences between SL1 and (L/F + 1) / 2, and between SL2
and (L/F + 1) / 2, are blanked.
Upper Panel
SL1
L
Lower Panel
Graphics
L/2
Figure 6-12: Two-panel Display Height
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3-3 CSRFORM
Set the cursor size and shape. Although the cursor is normally only used in text displays, it may
also be used in graphics displays when displaying special characters.
MSB
LSB
C
0
1
0
1
P1
0
0
0
0
P2
CM
0
0
0
1
1
0
1
X3
X2
X1
X0
Y3
CRY
Y1
Y2
Y0
CRX
Figure 6-13: CSRFORM Parameter Bytes
6-3-3-1 CRX
Set the horizontal size of the cursor from the character origin. CRX is equal to the cursor size less
one. CRX must be less than or equal to FX.
Table-14: Horizontal Cursor Size Selection
[CRX] cursor
CRX
width
HEX X3 X2 X1 X0
(pixels)
0
0
0
0
0
1
1
0
0
0
1
2
↓
↓ ↓ ↓ ↓
↓
4
0
1
0
0
9
↓
↓ ↓ ↓ ↓
↓
E
1
1
1
0
15
F
1
1
1
1
16
6-3-3-2 CRY
Set the location of an underscored cursor in lines, from the character origin. When using a block
cursor, CRY sets the vertical size of the cursor from the character origin. CRY is equal to the
number of lines less one.
Table-15: Cursor Height Selection
[CRY] cursor
CRY
height
HEX Y3 Y2 Y1 Y0
(lines)
0
0
0
0
0
Illegal
1
0
0
0
1
2
↓
↓
↓
↓
↓
↓
8
1
0
0
0
9
↓
↓
↓
↓
↓
↓
E
1
1
1
0
15
F
1
1
1
1
16
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Character start point
0
1
2
3
4
5
6
7
8
9
01 2 3 4 5 6‧‧‧
‧
CRX = 5 dots
CRY = 9 dots
CM = 0
Figure 6-14: Cursor Size and Position
6-3-3-3 CM
Set the cursor shape. Always set CM to 1 when in graphics mode.
CM = 0: Underscore cursor
CM = 1: Block cursor
6-3-4 CSRDIR
Set the direction of automatic cursor increment. The cursor can move left or right one character,
or up or down by the number of bytes specified by the address pitch, AP. When reading from and
writing to display memory, this automatic cursor increment controls the display memory address
increment on each read or write.
MSB
C
LSB
0
1
0
0
1
1
CD1
CD2
Figure 6-15: CSRDIR Parameters
10
01
-AP
-1
1
00
+AP
11
Figure 6-16: Cursor Direction
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-16: Cursor Shift Direction
C
CD1
CD0
Shift direction
4CH
0
0
Right
4DH
0
1
Left
4EH
1
0
Up
4FH
1
1
Down
Note: Since the cursor moves in address units even if FX ≥ 9 , the cursor address increment must
be preset for movement in character units. See Section 7-11.
6-3-5 OVLAY
Selects layered screen composition and screen text/ graphics mode.
MSB
LSB
C
0
1
0
1
1
0
1
1
P1
0
0
0
OV
DM2
DM1
MX1
MX0
Figure 6-17: OVLAY Parameters
6-3-5-1 MX0, MX1
MX0 and MX1 set the layered screen composition method, which can be either OR, AND,
Exclusive-OR or Priority- OR. Since the screen composition is organized in layers and not by
screen blocks, when using a layer divided into two screen blocks, different composition methods
cannot be specified for the individual screen blocks. The Priority-OR mode is the same as the OR
mode unless flashing of individual screens is used.
MX1
MX0
0
0
0
1
1
0
1
1
Table-17: Composition Method Selection
Functio
Composition Method
Applications
n
L1 ∪ L2
Underlining, rules, mixed text
OR
∪ L3
and graphics
(L1 ♁
Inverted characters, flashing
Exclusive-OR
L2) ∪ L3
regions, underlining
(L1 ∩
AND
L2) ∪ L3
Simple animation, threedimensional appearance
L1 > L2
Priority-OR
> L3
Notes:
L1: First layer (text or graphics). If text is selected, layer L3 cannot be used.
L2: Second layer (graphics only)
L3: Third layer (graphics only)
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Layer 1
Layer 2
Layer 3
Visible display
1
ABCDE
ABCDE
OR
2
ABCDE
ABCDE
Exclusive OR
3
ABCDE
CDE
4
ABCDE
ABCDE
AND
Prioritized OR
Figure 6-18: Combined Layer Display
Notes:
L1: Not flashing
L2: Flashing at 1 Hz
L3: Flashing at 2 Hz
6-3-5-2 DM1, DM2
DM1 and DM2 specify the display mode of screen blocks 1 and 3, respectively.
DM1/2 = 0: Text mode
DM1/2 = 1: Graphics mode
Note 1: Screen blocks 2 and 4 can only display graphics.
Note 2: DM1 and DM2 must be the same, regardless of the setting of W/S.
6-3-5-3 OV
Specifies two- or three-layer composition in graphics mode.
OV = 0: Two-layer composition
OV = 1: Three-layer composition
Set OV to 0 for mixed text and graphics mode.
6-3-6 CGRAM ADR
Specifies the CG RAM start address.
LSB
MSB
C
0
1
0
1
1
1
0
0
P1
A7
A6
A5
A4
A3
A2
A1
A0
SAGL
P2
A15
A14
A13
A12
A11
A10
A9
A8
SAGH
Figure 6-19: CGRAM ADR Parameters
Note: See Section 7-14 for information on the SAG parameters.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-3-7 HDOT SCR
While the SCROLL command only allows scrolling by characters, HDOT SCR allows the screen to
be scrolled horizontally by pixels. HDOT SCR cannot be used on individual layers.
MSB
LSB
C
0
1
0
1
1
0
1
0
P1
0
0
0
0
0
D2
D1
D0
Figure 6-20: HDOT SCR Parameters
6-3-7-1 D0 to D2
Specifies the number of pixels to scroll. The C/R parameter has to be set to one more than the
number of horizontal characters before using HDOT SCR. Smooth scrolling can be simulated if the
controlling microprocessor repeatedly issues the HDOT SCR command to the RA8835A series.
See Section 7-13 for more information on scrolling the display.
HEX
00
01
02
↓
06
07
Table-18: Scroll Step Selection
Number of pixels to
P1
scroll
D2 D1 D0
0
0
0
0
0
0
1
1
0
1
0
2
↓
↓
↓
↓
1
1
0
6
1
1
1
7
A
B
A
Z
Z
X
B
A
Y
B
X
Display width
M=0
N=0
Y
X
Y
N
M/N is the number of bits(dots) that parameter 1 (P1) is
incremented/decremented by.
Figure 6-21 Horizontal Scrolling
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-4 Drawing Control Commands
6-4-1 CSRW
The 16-bit cursor address register contains the display memory address of the data at the cursor
position as shown in Figure 6-22. Note that the microprocessor cannot directly access the display
memory. The MREAD and MWRITE commands use the address in this register.
LSB
MSB
C
0
1
0
0
0
1
1
0
P1
A7
A6
A5
A4
A3
A2
A1
A0
(CSRL)
P2
A15
A14
A13
A12
A11
A10
A9
A8
(CSRH)
Figure 6-22: CSRW Parameters
The cursor address register can only be modified by the CSRW command, and by the automatic
increment after an MREAD or MWRITE command. It is not affected by display scrolling. If a new
address is not set, display memory accesses will be from the last set address or the address after
previous automatic increments.
6-4-2 CSRR
Read from the cursor address register. After issuing the command, the data read address is read
twice, for the low byte and then the high byte of the register.
MSB
LSB
C
0
1
0
0
0
1
1
1
P1
A7
A6
A5
A4
A3
A2
A1
A0
(CSRL)
P2
A15
A14
A13
A12
A11
A10
A9
A8
(CSRH)
Figure 6-23: CSRR Parameters
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RA8835A
Version 1.3
Dot Matrix LCD Controller
6-5 Memory Control Commands
6-5-1 MWRITE
The microprocessor may write a sequence of data bytes to display memory by issuing the MREAD
command and then writing the bytes to the RA8835A series. There is no need for further MWRITE
commands or for the microprocessor to update the cursor address register after each byte as the
cursor address is automatically incremented by the amount set with CSRDIR, in preparation for the
next data write.
LSB
MSB
C
0
1
0
0
0
0
1
0
P1
P2
Pn
N>1
Figure 6-24: MWRITE Parameters
Note: P1, P2, ..., Pn: display data.
6-5-2 MREAD
Put the RA8835A series into the data output state. Each time the microprocessor reads the buffer,
the cursor address is incremented by the amount set by CSRDIR and the next data byte fetched
from memory, so a sequence of data bytes may be read without further MREAD commands or by
updating the cursor address register. If the cursor is displayed, the read data will be from two
positions ahead of the cursor.
LSB
MSB
C
0
1
0
0
0
0
1
1
P1
P2
Pn
N>1
Figure 6-25: MREAD Parameters
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7. Functions Description
7-1 MCU Bus Interface
SEL1, SEL2, A0, RD , WR and CS are used as control signals for the microprocessor data bus. A0 is
normally connected to the lowest bit of the system address bus. SEL1 and SEL2 change the operation
of the RD and WR pins to enable interfacing to either an 8080 or 6800 family bus, and should have a
pull-up or pull-down resistor. With microprocessors using an 8080 family interface, the RA8835A series
is normally mapped into the I/O address space.
7-1-1 8080 Series
Table-19: 8080 Series Interface Signals
A0
0
RD
0
WR
1
1
0
1
0
1
1
1
0
0
Function
Status flag read
Display data and cursor address
read
Display data and parameter write
Command write
7-1-2 6800 Series
Table-20A: 6800 Series Interface Signals
0
R/
W
1
1
1
1
0
1
0
0
1
1
A0
E
Function
1
Status flag read
Display data and cursor address
read
Display data and parameter write
Command write
7-2 MCU Synchronization
The RA8835A series interface operates at full bus speed, completing the execution of each command
within the cycle time, tCYC. The controlling microprocessor’s performance is thus not hampered by
polling or handshaking when accessing the RA8835A series.
Display flicker may occur if there is more than one consecutive access that cannot be ignored within a
frame. The microprocessor can minimize this either by performing these accesses intermittently, or by
continuously checking the status flag (D6) and waiting for it to become HIGH.
7-2-1 Display Status Indication Output
When CS , A0 and RD are LOW, D6 functions as the display status indication output. It is HIGH
during the TV-mode vertical retrace period or the LCD-mode horizontal retrace period, and LOW,
during the period the controller is writing to the display. By monitoring D6 and writing to the data
memory only during retrace periods, the display can be updated without causing screen flicker.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-2-2 Internal Register Access
The SYSTEM SET and SLEEP IN commands can be used to perform input/output to the RA8835A
series independently of the system clock frequency. These are the only commands that can be
used while the RA8835A series is in sleep mode.
7-2-3 Display Memory Access
The RA8835A series supports a form of pipelined processing, in which the microprocessor
synchronizes its processing to the RA8835A series timing. When writing, the microprocessor first
issues the MWRITE command. It then repeatedly writes display data to the RA8835A series using
the system bus timing. This ensures that the microprocessor is not slowed down even if the display
memory access times are slower than the system bus access times. See Figure 7-1A.
tCYC
WR
Command write
Microprocessor
Data write
Data write
D0 to D7
VR/ W
VRW
VD0 to VD7
Figure 7-1A: Display Memory Write Cycle
When reading, the microprocessor first issues the MREAD command, which causes the RA8835A
series to load the first read data into its output buffer. The microprocessor then reads data from the
RA8835A series using the system bus timing. With each read, the RA8835A series reads the next
data item from the display memory ready for the next read access. See Figure 7-1B.
Figure 7-1B: Display Memory Read Cycle
Note: A possible problem with the display memory read cycle is that the system bus access time,
tACC, does not depend on the display memory access time, tACV. The microprocessor may
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RA8835A
Version 1.3
Dot Matrix LCD Controller
only make repeated reads if the read loop time exceeds the RA8835A series cycle time, tCYC.
If it does not, NOP instructions may be inserted in the program loop. tACC, tACV and tCYC limits
are given in Section 10-2.
7-3 MCU Interface Examples
7-3-1 Z80 to RA8835A Interface
IORQ
A0
A1
to
A15
Z80
A0
Decoder
D0
to
D7
CS
D0
to
D7
RD
RD
WR
WR
RESET
RA8835
SEL1
SEL2
RES
RESET
Figure 7-2A: Z80 to RA8835A Interface
7-3-2 6802 to RA8835A Interface
VMA
A0
A0
A1
to
A15
6802
Decoder
CS
D0
to
D7
D0
to
D7
E
RD
R/W
WR
RESET
RA8835
RES
VDD
SEL1
SEL2
RESET
Figure 7-2B: 6802 to RA8835A Interface
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-4 Static RAM
The figure below shows the interface between an 8Kx8 static RAM and the RA8835A series. Note that
bus buffers are required if the bus is heavily loaded.
Note
VA0 to VA12
A0 to A12
HC138
VA13 toVA15
A-C
CS1
Y
VDD
RA8835
CE2
WRD
OE
VWR
WR
2764-pin
Compatible
memory
I/O1 to I/O8
VD0 to VD7
Figure 7-3: Static RAM Interface
Note: If the bus loading is too much, use a bus buffer.
7-5 Supply Current during Display Memory Access
The 24 address and data lines of the RA8835A series cycle at one-third of the oscillator frequency, fOSC.
The charge and discharge current on these pins, IVOP, is given by the equation below. When IVOP
exceeds IOPR, it can be estimated by:
IVOP ∝ C V f
Where C is the capacitance of the display memory bus, V is the operating voltage, and f is the
operating frequency. If VOPR = 5.0V, f = 1.0 MHz, and the display memory bus capacitance is 1.0 pF
per line:
IVOP ≤ 120 mA / MHz x pF
To reduce current flow during display memory accesses, it is important to use low-power memory, and
to minimize both the number of devices and the parasitic capacitance.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-6 Oscillator Circuit
The RA8835A series incorporates an oscillator circuit. A stable oscillator can be constructed simply by
connecting an AT-cut crystal and two capacitors to XG and XD, as shown in the figure below. If the
oscillator frequency is increased, CD and CG should be decreased proportionally. Note that the circuit
board lines to XG and XD must be as short as possible to prevent wiring capacitance from changing
the oscillator frequency or increasing the power consumption.
Figure 7-4: Crystal Oscillator
7-7 Status Flag
The RA8835A series has a single bit status flag.
D6: X line standby
Figure 7-5: Status Flag
The D6 status flag is HIGH for the tC/R period, and go Low at tTC/R - tC/R period where the RA8835A
series is not reading the display memory. The microprocessor may use this period to update display
memory without affecting the display, however it is recommended that the display be turned off when
refreshing the whole display.
LP
tTC/R
tm
tC/R
XSCL
Figure 7-6: C/R to TC/R Time Difference
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RA8835A
Version 1.3
Dot Matrix LCD Controller
CS
A0
RD
0
0
0
D6(flag)
0: Period of retrace lines
1: Period of display
Figure 7-7: Flowchart for Busy Flag Checking
• Precaution on the write timing to VRAM
The allowable writing duration is since “5 x 9 x tOSC” has elapsed (tOSC = 1/fOSC: a cycle of the oscillation
frequency) from the positive going edge of LP up to {(TCR) – (C/R) – 7} x 9 x tOSC.
Currently employed D6 status flag reading method does not identify the timing when the read D6 =
Low took place. Thus, negative going edge of LP should be used as the interrupt signal when
implementing the writing in above timing. If you try to access the display memory in other timing than
the above, flickering of the display screen will result.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-8 Reset
VDD
10*tc reset
pulse
0.7VDD
RES
0.3VDD
Figure 7-8: Reset Timing
The RA8835A series requires a reset pulse at least 10*tc long after power-on in order to re-initialize its
internal state. If the oscillator frequency is 10Mhz, then the Reset pulse is at least 1µs. For maximum
reliability, it is not recommended to apply a DC voltage to the LCD panel while the RA8835A series is
reset. Turn off the LCD power supplies for at least one frame period after the start of the reset pulse.
The RA8835A series cannot receive commands while it is reset. Commands to initialize the internal
registers should be issued soon after a reset. During reset, the LCD drive signals XD, LP and FR are
halted. A delay of 3 ms (minimum) is required following the rising edges of both RES and VDD to
allow for system stabilization.
7-9 Character Configuration
The origin of each character bitmap is in the top left corner as shown in Figure 7-9. Adjacent bits in
each byte are horizontally adjacent in the corresponding character image. Although the size of the
bitmap is fixed by the character generator, the actual displayed size of the character field can be varied
in both dimensions.
Character start point
FX
Character
height
FY
Space
Character Space
width
data
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
R15
D7
0 1
1 0
1 0
1 0
1 1
1 0
1 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
1
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
to
1 0
0 1
0 1
0 1
1 1
0 1
0 1
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0 0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
D0
0
0
0
0
0
0
0
0
0
0
0
0 Space
0 data
0
0
0
Space
data
Figure 7-9: Example of Character Display ([FX] ≤ 8) and Generator Bitmap
If the area outside the character bitmap contains only zeros, the displayed character size can easily be
increased by increasing FX and FY, as the zeros ensure that the extra space between displayed
characters is blank. The displayed character width can be set to any value up to 16 even if each
horizontal row of the bitmap is two bytes wide.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Horizontal
non-display
area
FX
Character
Hight
FY
16 dots
Space
8 dots
8 dots
Character
width
Space
data
Figure 7-10: Character Width Greater Than One Byte Wide ([FX]=9)
Note: The RA8835A series does not automatically insert spaces between characters. If the displayed
character size is 8 pixels or less and the space between character origins is nine pixels or
more, the bitmap must use two bytes per row, even though the character image requires only
one.
7-10 Screen Configuration
7-10-1 Screen Configuration
Character
memory area
A/P
C/R
0000H
0800H
07FFH
Graphics
memory area
Display
memory
window
47FFH
(0,YM)
(XM,YM)
(X,Y)
Y
(0,0)
(XM,0)
X
Figure 7-11: Virtual and Physical Screen Relationship
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RA8835A
Version 1.3
Dot Matrix LCD Controller
The basic screen configuration of the RA8835A series is as a single text screen or as overlapping
text and graphics screens. The graphics screen uses eight times as much display memory as the
text screen. Figure 7-11 shows the relationship between the virtual screens and the physical
screen.
7-10-2 Display Address Scanning
The RA8835A series scans the display memory in the same way as a raster scan CRT screen.
Each row is scanned from left to right until the address range equals C/R. Rows are scanned
from top to bottom.
In graphics mode, at the start of each line, the address counter is set to the address at the start of
the previous line plus the address pitch, AP.
1
‧
‧
8
9
‧
‧
16
17
‧
‧
SAD
SAD+AP
SAD+1
SAD+2
SAD+C/R
SAD+AP
+1
SAD+AP
+2
SAD+AP
+C/R
SAD+2AP
24
‧
‧
‧
C/R
WS=0,FX=8,FY=8
Figure 7-12: Character Position Parameters
Note: One byte of display memory corresponds to one character.
1
SAD
2
SAD+AP
3
SAD+2AP
SAD+1
SAD+2
SAD+C/R
SAD+AP
+1
SAD+AP
+2
SAD+AP
+C/R
SAD
SAD+1
SAD+2
Line 1
AP
SAD+C/R
‧
‧
‧
‧
‧
‧
SAD+AP
SAD+AP+1
Line 2
AP
SAD+AP+C/R
SAD+2AP
C/R
Line 3
WS=0,FX=8
Figure 7-13: Character Parameters vs. Memory
Note: One bit of display memory corresponds to one pixel.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
In text mode, the address counter is set to the same start address, and the same character data
is read, for each row in the character bitmap. However, a new row of the character generator
output is used each time. Once all the rows in the character bitmap have been displayed, the
address counter is set to the start address plus AP and the next line of text is displayed.
1
‧
‧
8
9
‧
‧
16
17
‧
‧
SAD+C/R
SAD
SAD+1
SAD1+2
SAD1+AP
SAD1+AP SAD1+AP
+1
+2
SAD1+AP
+C/R
SAD1+2AP
24
‧
‧
‧
(L/F)/2=β
β+1
SAD3+2
‧ SAD3+1
‧
β+8
β+9
‧ SAD3+AP SAD3+AP SAD3+AP
+1
+2
‧
β+1
β+1
6
7
‧ SAD3+2AP
‧
β+2
4
β+2
5
‧
‧
‧
SAD3+C/R
SAD3+AP
+C/R
(L/F)
C/R
WS=1,FX=8,FY=8
Figure 7-14: Two-panel Display Address Indexing
Note: In two-panel drive, the RA8835A series reads line 1 and line b + 1 as one cycle. The upper
and lower panels are thus read alternately, one line at a time.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-10-3 Display Scan Timing
Figure 7-15 shows the basic timing of the RA8835A series. One display memory read cycle takes
nine periods of the system clock, ψ0 (fOSC ). This cycle repeats (C/R + 1) times per display line.
When reading, the display memory pauses at the end of each line for (TC/R - C/R) display
memory read cycles, though the LCD drive signals are still generated. TC/R may be set to any
value within the constraints imposed by C/R, fOSC , fFR , and the size of the LCD panel, and it may
be used to fine tune the frame frequency. The microprocessor may also use this pause to access
the display memory data.
￠
0
T0
T1
T2
Display read cycle interal
VCE
Character read interal
Graphics read interal
Graphics generator
read interal
VA
Figure 7-15: Display Memory Basic Read Cycle
Display period
Divider frequency
period
TC/R
C/R
Frame
period
Line 1
0
R
2
0
R
3
0
R
‧
‧
‧
‧
(L/F)
0
R
LP
Figure 7-16: Relationship Between TC/R and C/R
Note: The divider adjustment interval (R) applies to both the upper and lower screens even if
W/S = 1. In this case, LP is active only at the end of the lower screen’s display interval.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-11 Cursor Control
7-11-1 Cursor Register Function
The RA8835A series cursor address register functions as both the displayed cursor position
address register and the display memory access address register. When accessing display
memory outside the actual screen memory, the address register must be saved before accessing
the memory and restored after memory access is complete.
Figure 7-17: Cursor Addressing
Note that the cursor may disappear from the display if the cursor address remains outside the
displayed screen memory for more than a few hundred milliseconds.
7-11-2 Cursor Movement
On each memory access, the cursor address register changes by the amount previously
specified with CSRDIR, automatically moving the cursor to the desired location.
7-11-3 Cursor Display Layers
Although the RA8835A series can display up to three layers, the cursor is displayed in only one of
these layers: Two-layer configuration: First layer (L1) Three-layer configuration: Third layer (L3)
The cursor will not be displayed if it is moved outside the memory for its layer. Layers may be
swapped or the cursor layer moved within the display memory if it is necessary to display the
cursor on a layer other than the present cursor layer.
Although the cursor is normally displayed for character data, the RA8835A series may also
display a dummy cursor for graphical characters. This is only possible if the graphics screen is
displayed, the text screen is turned off and the microprocessor generates the cursor control
address.
Figure 7-18: Cursor Display Layers
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Consider the example of displaying Chinese characters on a graphics screen. To write the
display data, the cursor address is set to the second screen block, but the cursor is not displayed.
To display the cursor, the cursor address is set to an address within the blank text screen block.
Since the automatic cursor increment is in address units, not character units, the controlling
microprocessor must set the cursor address register when moving the cursor over the graphical
characters.
Figure 7-19: Cursor Movement
If no text screen is displayed, only a bar cursor can be displayed at the cursor address.
If the first layer is a mixed text and graphics screen and the cursor shape is set to a block cursor,
the RA8835A series automatically decides which cursor shape to display. On the text screen it
displays a block cursor, and on the graphics screen, a bar cursor.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-12 Memory to Display Relationship
The RA8835A series supports virtual screens that are larger than the physical size of the LCD panel
address range, C/R. A layer of the RA8835A series can be considered as a window in the larger
virtual screen held in display memory. This window can be divided into two blocks, with each block
able to display a different portion of the virtual screen.
This enables, for example, one block to dynamically scroll through a data area while the other acts as
a status message display area. See Figure 7-20 and 7-21.
AP
C/R
SAD1
W/S=0
Character page1
SAD1
Character page3
SAD3
SAD3
Display page 1
W/S=1
Graphics page 1
Graphics page 3
Graphics page 2
Layer 1
SAD2
Graphics page 2
SAD4
Display page 2
Layer 1
Graphics page 2
Graphics page 4
C/R
Layer 2
Layer 2
CG RAM
SAD1
C/R
Character page1
SAD1
Display page1
SAD3
Display page3
C/R
SAD3
Graphics page 3
Layer 1
C/R
SAD2
SAD2
Display page2
Graphics page 2
Layer 2
C/R
SAD3
Character page3
C/R
SAD3
SAD2
SAD2
Graphics page 2
Display page3
C/R
Display page2
SAD1
SAD1
Display page1
Graphics page 1
Layer 1
Layer 2 Layer 3
Figure 7-20: Display Layers and Memory
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Figure 7-21: Display Windows and Memory
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Figure 7-22: Memory Map and Magnified Characters
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-13 Scrolling
The controlling microprocessor can set the RA8835A series scrolling modes by overwriting the scroll
address registers SAD1 to SAD4, and by directly setting the scrolling mode and scrolling rate.
7-13-1 On-page Scrolling
The normal method of scrolling within a page is to move the whole display up one line and erase
the bottom line. Since the RA8835A series does not automatically erase the bottom line, it must
be erased with blanking data when changing the scroll address register.
Figure 7-23: On-page Scrolling
7-13-2 Inter-page Scrolling
Scrolling between pages and page switching can be performed only if the display memory
capacity is greater than one screen.
Figure 7-24: Inter-page Scrolling
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-13-3 Horizontal Scrolling
The display can be scrolled horizontally in one-character units, regardless of the display memory
capacity.
Figure 7-25: Horizontal Wraparound Scrolling
7-13-4 Bi-directional Scrolling
Bi-directional scrolling can be performed only if the display memory is larger than the physical
screen both horizontally and vertically. Although scrolling is normally done in single-character
units, the HDOT SCR command can be used to scroll horizontally in pixel units. The Single-pixel
scrolling of both horizontally and vertically can be performed by using the SCROLL and HDOT
SCR commands. See Section 8-4.
Figure 7-26: Bi-directional Scrolling
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-13-5 Scroll Units
Table-20B: Scroll Units
Mode
Vertical
Horizontal
Pixels or
Text
Characters
characters
Graphics
Pixels
Pixels
Note that in a divided screen, each block cannot be independently scrolled horizontally in pixel
units.
7-14 CG Characteristics
7-14-1 Internal Character Generator
The internal character generator is recommended for minimum system configurations containing
a RA8835A series, display RAM, LCD panel, single-chip microprocessor and power supply. Since
the internal character generator uses a CMOS mask ROM, it is also recommended for low-power
applications.
• 5 x 7-pixel font (See Section 8-7.)
• 160 JIS standard characters
• Can be mixed with character generator RAM (maximum of 64 CG RAM characters)
• Can be automatically spaced out up to 8 x 16 pixels
7-14-2 External Character Generator ROM
The external CG ROM can be used when fonts other than those in the internal ROM are needed.
Data is stored in the external ROM in the same format used in the internal ROM. (See Section 716)
• Up to 8 x 8-pixel characters (M2 = 0) or 8 x 16-pixel characters (M2 = 1)
• Up to 256 characters (192 if used together with the internal ROM)
• Mapped into the display memory address space at F000H to F7FFH (M2 = 0) or F000H to
FFFFH (M2 = 1)
• Characters can be up to 8 x 16-pixels; however, excess bits must be set to zero.
7-14-3 Character Generator RAM
The user can freely use the character generator RAM for storing graphics characters. The
character generator RAM can be mapped by the microprocessor anywhere in display memory,
allowing effective use of unused address space.
• Up to 8 x 8-pixel characters (M2 = 0) or 8 x 16 characters (M2 = 1)
• Up to 256 characters if mapped at F000H to FFFFH (64 if used together with character
generator ROM)
• Can be mapped anywhere in display memory address space if used with the character
generator ROM
• Mapped into the display memory address space at F000H to F7FFH if not used with the
character generator ROM (more than 64 characters are in the CG RAM). Set SAG0 to
F000H and M1 to zero when defining characters number 193 upwards.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-15 CG Memory Allocation
Since the RA8835A series uses 8-bit character codes, it can handle no more than 256 characters at a
time. However, if a wider range of characters is required, character generator memory can be bankswitched using the CGRAM ADR command.
Figure 7-27: Internal and External Character Mapping
Note that there can be no more than 64 characters per bank.
Table-21: Character Mapping
Item
Parameter
Internal/external character generator
M0
selection
1 to 8 pixels
M2 = 0
Character field
9 to 16 pixels
M2 = 1
height
Greater than 16 pixels
Graphics mode (8 bits ´1 line)
Internal CG ROM/RAM select
Automatic
External CG ROM/RAM select
CG RAM bit 6 correction
M1
CG RAM data storage address
External CG
ROM
Address
192 characters or less
More than 192
characters
RAiO TECHNOLOGY INC.
Specified with CG RAM ADR
command
Remarks
Determined by the character
code
Can be moved anywhere in
the display memory address
space
Other than the area of Figure
7-2A
Set SAG to F000H and overly
SAG and the CG ROM table
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-16 Setting Character Generator Address
The CG RAM addresses in the VRAM address space are not mapped directly from the address in the
SAG register. The data to be displayed is at a CG RAM address calculated from SAG + character
code + ROW select address. This mapping is shown in Table-22A and –22B.
SAG
Character code
+ROW select
address
CG RAM address
Table-22A: Character Fonts, Number of Lines ≤ 8 (M2 = 0, M1 = 0)
A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3
A2
A1
A0
0
0
0
0
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R2
R1
R0
VA8
VA7
VA6
VA5
VA4
VA3
VA2
VA1
VA0
VA15 VA14 VA13 VA12 VA11 VA10 VA9
Table-22B: Character Fonts, 9 ≤ Number of Lines ≤ 16 (M2 = 1, M1 = 0)
A15 A14 A13 A12 A11 A10 A9 A8 A7 A6 A5 A4 A3 A2
SAG
Character code
+ROW select
address
CG RAM address
A1
A0
0
0
0
0
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
R3
R2
R1
R0
VA15 VA14 VA13 VA12 VA11 VA10 VA9 VA8 VA7 VA6 VA5 VA4 VA3 VA2 VA1 VA0
Figure 7-28: Row Select Address
Note: Lines = 1: lines in the character bitmap ≤ 8
Lines = 2: lines in the character bitmap ≤ 9
7-16-1 M1 = 1
The RA8835A series automatically converts all bits set in bit 6 of character code for CG RAM 2 to
zero. Because of this, the CG RAM data areas become contiguous in display memory.
When writing data to CG RAM:
• Calculate the address as for M1 = 0.
• Change bit 6 of the character code from “1” to “0”.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-16-2 CG RAM Addressing Example
• Define a pattern for the “A” in Figure 7-9.
• The CG RAM table start address is 4800H.
• The character code for the defined pattern is 80H (the first character code in the CG RAM
area).
As the character code table in Figure 7-29 shows, codes 80H to 9FH and E0H to FFH are
allocated to the CG RAM and can be used as desired. 80H is thus the first code for CG RAM. As
characters cannot be used if only using graphics mode, there is no need to set the CG RAM data.
Table-23: Character Data Example
CGRAM AD
5CH
Reverse the CG RAM address calculation to calculate SAG
P1
00H
P2
40H
CSRDIR
4CH
CSRW
46H
P1
00H
P2
48H
MWRITE
42H
P
70H
Write ROW 0 data
P2
88H
Write ROW 1 data
P3
88H
Write ROW 2 data
P4
88H
Write ROW 3 data
P5
F8H
Write ROW 4 data
P6
88H
Write ROW 5 data
P7
88H
Write ROW 6 data
P8
00H
Write ROW 7 data
P8
00H
Write ROW 8 data
↓
↓
P16
00H
RAiO TECHNOLOGY INC.
Set cursor shift direction to right
CG RAM start address is 4800H
↓
Write ROW 15 data
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RA8835A
Version 1.3
Dot Matrix LCD Controller
7-17 Character Codes
The following figure shows the character codes and the codes allocated to CG RAM. The CG RAM if
not using the internal ROM can use all codes.
Upper 4bites
Lower 4bites
0
1
2
3
4
5
6
7
0
@
P
｀
p
1
!
1
A
Q
a
q
2
“
2
B
R
b
r
3
#
3
C
S
c
s
4
$
4
D
T
d
t
5
&
5
E
U
e
u
6
%
6
F
V
f
v
7
'
7
G
W
g
w
8
(
8
H
X
h
x
)
9
I
Y
i
y
A
*
:
J
Z
j
z
B
+
;
K
[
k
{
C
,
<
L
¥
l
¦
D
.
=
M
]
m
}
E
-
>
N
^
n
→
F
/
?
O
_
o
←
0
9
8
9
CG RAM 1
A
B
C
D
E
F
CG RAM2
M1=0
M1=1
Figure 7-29: On-chip Character Codes
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8. Application Notes
8-1 Initialization Parameters
The parameters for the initialization commands must be determined first. Square brackets around a
parameter name indicate the number represented by the parameter, rather than the value written to the
parameter register. For example, [FX] = FX + 1.
8-1-1 System Set Instruction and Parameters
◎ FX
The horizontal character field size is determined from the horizontal display size in pixels [VD] and the
number of characters per line [VC].
[VD]
≤ [FX]
[VC]
◎ C/R
C/R can be determined from VC and FX.
[C/R] = RND(
[FX]
) × [VC]
8
Where RND(x) denotes ´ rounded up to the next highest integer. [C/R] is the number of bytes per line,
not the number of characters.
◎ TC/R
TC/R must satisfy the condition [TC/R] ≥ [C/R] + 4 .
◎ fOSC and fFR
Once TC/R has been set, the frame frequency, fFR, and lines per frame [L/F] will also have been set.
The lower limit on the oscillator frequency fOSC is given by:
fOSC ≥ ([TC/R] + 1) × 9 × ([L/F] + 1) × fFR
◎ If no standard crystal close to the calculated value of fOSC exists, a higher frequency crystal can be
used and the value of TC/R revised using the above equation.
◎ Symptoms of an incorrect TC/R setting are listed below. If any of these appears, check the value of
TC/R and modify it if necessary.
• Vertical scanning halts and a high-contrast horizontal line appears.
• All pixels are on or off.
• The LP output signal is absent or corrupted.
• The display is unstable.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-24: RAiO LCD Unit Example Parameters
Product name
and resolution
(X ´Y)
256 x 64
512 x 64
256 x 128
512 x 128
[FX]
[FX] = 6 pixels:
256 / 6 = 42
remainder 4 = 4
blank pixels
[FX] = 6 pixels:
512 / 6 = 85
remainder 2 = 2
blank pixels
[FX] = 8 pixels:
256 / 8 = 32
remainder 0 = no
blank pixels
[FX] = 10 pixels:
512 / 10 = 51
remainder 2 = 2
blank pixels
[FY]
8 or 16, depending
on the screen
8 or 16, depending
on the screen
8 or 16, depending
on the screen
8 or 16, depending
on the screen
[C/R]
[C/R] = 42 = 2AH
bytes:
C/R = 29H. When
using HDOT SCR,
[C/R] = 43 bytes
[C/R] = 85 = 55H
bytes:
C/R = 54H. When
using HDOT SCR,
[C/R] = 86 bytes
[C/R] = 32 = 20H
bytes:
C/R = 19H. When
using HDOT SCR,
[C/R] = 33 bytes
[C/R] = 102 = 66H
bytes:
C/R = 65H. When
using HDOT SCR,
[C/R] = 103 bytes
TC/R
fOSC (MHz)
See Note 2.
2DH
1.85
58H
3.59
22H
2.90
69H
8.55
Notes:
1. The remainder pixels on the right-hand side of the display are automatically blanked by the
RA8835A. There is no need to zero the display memory corresponding to these pixels.
2. Assuming a frame frequency of 60 Hz.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-1-2 Initialization Example
The initialization example shown in Figure 8-1 is for a RA8835A series with an 8-bit
microprocessor interface bus and a display unit (320 x 240 pixels).
Figure 8-1: Initialization Procedure
Note: Set the cursor address to the start of each screen’s layer memory, and use MWRITE to fill
the memory with space characters, 20H (text screen only) or 00H (graphics screen only).
Determining which memory to clear is explained in Section 8-1-3.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
No.
1
2
3
4
Table-25: Initialization Procedure
Command
Operation
Power-up
Supply
SYSTEM SET
C = 40H
P1 = 30H
M0: Internal CG ROM
M1: CG RAM is 32 characters maximum
M2: 8 lines per character
W/S: Two-panel drive
IV: No top-line compensation
P2 = 87H
FX: Horizontal character size = 8 pixels
WF: Two-frame AC drive
P3 = 07H
FY: Vertical character size = 8 pixels
P4 = 27H
C/R: 39 display addresses per line
P5 = 2FH
TC/R: Total address range per line = 47
fOSC = 8.0 MHz, fFR = 70 Hz
P6 = EFH
L/F: 239 display lines
AP: Virtual screen horizontal size is 40
P7 = 28H
addresses
P8 = 00H
SCROLL
C = 44H
P1 = 00H
First screen block start address
P2 = 00H
Set to 0000H
P3 = F0H
Display lines in first screen block = 240
P4 = 80H
Second screen block start address
P5 = 25H
Set to 1000H
P6 = F0H
Display lines in second screen block = 240
P7 = 00H
Third screen block start address
P8 = 4BH
Set to 4B00H
P9 = 00H
Fourth screen block start address
P10 = 00H
Set to 0000H
Display memory
5
HDOT SCR
C = 5AH
P1 = 00H
(SAD1) 0000H
1st display memory page
(SAD2) 2580H
2nd display memory page
(SAD3) 4B00H
3rd display memory page
(SAD4) 0000H
4th display memory page
Set horizontal pixel shift to zero
(continued)
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RA8835A
Version 1.3
Dot Matrix LCD Controller
No.
6
7
8
9
Table-25: Initialization Procedure (continued)
Command
Operation
OVLAY
C = 5BH
P1 = 01H
MX 1, MX 0: Inverse video superposition
DM 1: First screen block is text mode
DM 2: Third screen block is text mode
DISP ON/OFF
C = 58H
D: Display OFF
P1 = 56H
FC1, FC0: Flash cursor at 2 Hz
FP1, FP0: First screen block ON
FP3, FP2: Second and fourth screen blocks
ON
FP5, FP4: Third screen block ON
Fill first screen layer memory with 20H (space
Clear data in first layer
character)
Fill second screen layer memory with 00H
Clear data in second layer
(blank data)
Display
Character code in every position
1st layer
Black code in every position
2nd layer
10
11
CSRW
C = 46H
P1 = 00H
P2 = 00H
CSR FORM
C = 5DH
P1 = 04H
P2 = 86H
12
DISP ON/OFF
C = 59H
Set cursor to start of first screen block
CRX: Horizontal cursor size = 5 pixels
CRY: Vertical cursor size = 7 pixels
CM: Block cursor
Display ON
Display
13
CSR DIR
C = 4CH
Set cursor shift direction to right
(continued)
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RA8835A
Version 1.3
Dot Matrix LCD Controller
No.
14
15
16
17
18
19
Table-25: Initialization Procedure (continued)
Command
Operation
MWRITE
C = 42H
P1 = 20H
‘‘
P2 = 52H
‘R’
P3 = 41H
‘A’
P4 = 49H
‘I’
P5 = 4FH
‘O’
CSRW
C = 46H
P1 = 00H
P2 = 10H
CSR DIR
C = 4FH
MWRITE
C = 42H
P1 = FFH
↓
P9 = FFH
CSRW
C = 46H
P1 = 01H
P2 = 10H
MWRITE
C = 42H
P1 = FFH
Set cursor to start of second screen block
Set cursor shift direction to down
Fill a square to the left of the ‘E’
Set cursor address to 1001H
Fill in the second screen block in the second
column of line 1
↓
P9 = FFH
(continued)
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Table-25: Initialization Procedure (continued)
Command
Operation
Repeat operations 18 and 19 to fill in the
CSRW
background under ‘RAIO’
No.
20
↓
29
MWRITE
30
CSRW
31
C = 46H
P1 = 00H
P2 = 01H
CSR DIR
C = 4CH
MWRITE
C = 42H
32
Set cursor to line three of the first screen block
Set cursor shift direction to right
Inverse display
P1 = 44H
RAIO
‘D’
Dot matrix LCD
P2 = 6FH
P3 = 74H
P4 = 20H
P5 = 4DH
P6 = 61H
P7 = 74H
P8 = 72H
P9 = 69H
P10 = 78H
P11 = 20H
P12 = 4CH
P13 = 43H
P14 = 44H
RAiO TECHNOLOGY INC.
‘o’
‘t’
‘’
‘M’
‘a’
‘t’
‘r’
‘i’
‘x’
‘’
‘L’
‘C’
‘D’
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-1-3 Display Mode Setting Example 1: combining text and graphics
◎ Conditions
„
320 x 200 pixels, single-panel drive (1/200 duty cycle)
„
First layer: text display
„
Second layer: graphics display
„
8 x 8-pixel character font
„
CG RAM not required
◎ Display Memory Allocation
„
First layer (text): 320/8 = 40 characters per line, 200/8 = 25 lines. Required memory
size = 40 x 25 = 1000 bytes.
„
Second layer (graphics): 320/8 = 40 characters per line, 200/1 = 200 lines. Required
memory size = 40 x 200 = 8000 bytes.
Figure 8-2: Character Over Graphics Layers
◎ Register Setup Procedure
SYSTEM SET
TC/R calculation
C = 40H
P1 = 30H
fOSC = 6 MHz
P2 = 87H
fFR = 70 Hz
P3 = 07H
P4 = 27H
(1/6) x 9 x [TC/R] x 200 = 1/70
P5 = 2FH
[TC/R] = 48, so TC/R = 2FH
P6 = C7H
P7 = 28H
P8 = 00H
SCROLL
C = 44H
P1 = 00H
P2 = 00H
P3 = C8H
P4 = E8H
P5 = 03H
P6 = C8H
P7 = XH
P8 = XH
P9 = XH
P10 = XH
CSR FORM
C = 5DH
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RA8835A
Version 1.3
Dot Matrix LCD Controller
P1 = 04H
P2 = 86H
HDOT SCR
C = 5AH
P1 = 00H
OVLAY
C = 5BH
P1 = 00H
DISP ON/OFF
C = 59H
P1 = 16H
X = Don’t care
8-1-4 Display Mode Setting Example 2: combining graphics and graphics
◎ Conditions
„
320x200 pixels, single-panel drive (1/ 200 duty cycle)
„
First layer: graphics display
„
Second layer: graphics display
◎ Display Memory Allocation
„
First layer (graphics): 320/8 = 40 characters per line, 200/1 = 200 lines. Required
memory size = 40x200 = 8000 bytes.
„
Second layer (graphics): 320/8 = 40 characters per line, 200/1 = 200 lines. Required
memory size = 8000 bytes.
1F40H
2nd graphics layer
(8000 bytes)
0000H
1st graphics layer
(8000 bytes)
3E7FH
1F3FH
Figure 8-3: Two Layer Graphics
◎ Register Setup Procedure
SYSTEM SET
TC/R calculation
C = 40H
P1 = 30H
fOSC = 6 MHz
P2 = 87H
fFR = 70 Hz
P3 = 07H
P4 = 27H
(1/6) x 9 x [TC/R] x 200 = 1/70
P5 = 2FH
[TC/R] = 48, so TC/R = 2FH
P6 = C7H
P7 = 28H
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RA8835A
Version 1.3
Dot Matrix LCD Controller
P8 = 00H
SCROLL
C = 44H
P1 = 00H
P2 = 00H
P3 = C8H
P4 = 40H
P5 = 1FH
P6 = C8H
P7 = XH
P8 = XH
P9 = XH
P10 = XH
CSR FORM
C = 5DH
P1 = 07H
P2 = 87H
HDOT SCR
C = 5AH
P1 = 00H
OVLAY
C = 5BH
P1 = 0CH
DISP ON/OFF
C = 59H
P1 = 16H
X = Don’t care
8-1-5 Display Mode Setting Example 3: combining three graphics layers
◎ Conditions
„
320x200 pixels, single-panel drive (1/200 duty cycle)
„
First layer: graphics display
„
Second layer: graphics display
„
Third layer: graphics display
◎ Display Memory Allocation
„
All layers (graphics): 320/8 = 40 characters per line, 200/1 = 200 lines. Required
memory size = 40x200 = 8000 bytes.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
3E80H
3rd graphics layer
(8000 bytes)
1F40H
2nd graphics layer
(8000 bytes)
5DBFH
0000H
1st graphics layer
(8000 bytes)
3E7FH
1F3FH
Figure 8-4: Three Layer Graphics
◎ Register Setup Procedure
SYSTEM
SET TC/R calculation
C = 40H
P1 = 30H
fOSC = 6 MHz
P2 = 87H
fFR = 70 Hz
P3 = 07H
P4 = 27H
(1/6) x 9 x [TC/R] x 200 = 1/70
P5 = 2FH
[TC/R] = 48, so TC/R = 2FH
P6 = C7H
P7 = 28H
P8 = 00H
SCROLL
C = 44H
P1 = 00H
P2 = 00H
P3 = C8H
P4 = 40H
P5 = 1FH
P6 = C8H
P7 = 80H
P8 = 3EH
P9 = XH
P10 = XH
CSR FORM
C = 5DH
P1 = 07H
P2 = 87H
HDOT SCR
C = 5AH
P1 = 00H
OVLAY
C = 5BH
P1 = 1CH
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RA8835A
Version 1.3
Dot Matrix LCD Controller
DISP ON/OFF
C = 59H
P1 = 16H
X = Don’t care
8-2 System Overview
Figure 8-5 shows the RA8835A series in a typical system. The microprocessor issues instructions to
the RA8835A series, and the RA8835A series drives the LCD panel and may have up to 64KB of
display memory. Since all of the LCD control circuits are integrated onto the RA8835A series, few
external components are required to construct a complete medium- resolution liquid crystal display.
RA8835A
RA8835
Character
generator
Microprocessor
Display
Address
control
Driver
control
Display memory
Address bus
Exter character
Generator memory
Display memory
Display memory
data bus
LCD unit
Drive bus
Mainmemory
X drive
Y drive
Data bus
Address bus
Control bus
X drive
X drive
LCD panel
Figure 8-5: System Block Diagram
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-3 System Interconnection
10MHz crystal
A0
A0
Micro processor
A1
To
A7
XG
CS
Decoder
XD
VA13
To
VA15
VCE
HC138
Y7
A Y6
B
to
C Y0
CS 7
CS 6
to
CS 0
VRD
VA0
RA8835A
RA8835
IORQ
To
VA 12
D0
to
D7
RD
RD
WR
WR
RESET
A0 to A 12 WE
(RAM 2) CS 1
CS 2
D0 to D 7 OE
D0 to D 7 OE
A0 to A 11
(CGROM )
OE
CE
D0 to D 7
VD0
To
VD7
XECL
XSCL
LP
WF
YDIS
YD
YSCL
RESET
RESET
XD0
To
XD3
A0 to A 12 WE
(RAM 1) CS 1
CS 2
LAT
DI
LCD
INH
FR
YSCL
POFF
E0
V3
FR
EI
E0
FR
EI
E0
LP
XSCL
ECL
D0
to
D3
FR
EI
V2
LP
XSCL
ECL
D0
to
D3
V REG
V1
LP
XSCL
ECL
D0
to
D3
Power
Supply
converter
V4
V5
LCD UNIT
Figure 8-6: System Interconnection Diagram
The RA8835A series layered screens and flexible scrolling facilities support a range of display
functions and reduces the load on the controlling microprocessor when displaying underlining,
inverse display, text overlaid on graphics or simple animation.
These facilities are supported by the RA8835A series ability to divide display memory into up to
four different areas.
◎ Character code table
„
Contains character codes for text display
„
Each character requires 8 bits
„
Table mapping can be changed by using the scroll start function
◎ Graphics data table
„
Contains graphics bitmaps
„
Word length is 8 bits
„
Table mapping can be changed
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RA8835A
Version 1.3
Dot Matrix LCD Controller
◎ CG RAM table
„
Character generator memory can be modified by the external microprocessor
„
Character sizes up to 8x16-pixels (16 bytes per character)
„
Maximum of 64 characters
„
Table mapping can be changed
◎ CG ROM table
„
Used when the internal character generator is not adequate
„
Can be used in conjunction with the internal character generator and external
character generator RAM
„
Character sizes up to 8x16-pixels (16 bytes per character)
„
Maximum of 256 characters
„
Fixed mapping at F000H to FFFFH
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-4 Smooth Horizontal Scrolling
Figure 8-7 illustrates smooth display scrolling to the left. When scrolling left, the screen is effectively
moving to the right, over the larger virtual screen. Instead of changing the display start address SAD
and shifting the display by eight pixels, smooth scrolling is achieved by repeatedly changing the pixelshift parameter of the HDOT SCR command. When the display has been scrolled seven pixels, the
HDOT SCR pixel-shift parameter is reset to zero and SAD incremented by one. Repeating this
operation at a suitable rate gives the appearance of smooth scrolling.
To scroll the display to the right, the reverse procedure is followed. When the edge of the virtual screen
is reached, the microprocessor must take appropriate steps so that the display is not corrupted. The
scroll must be stopped or the display modified.
Note that the HDOT SCR command cannot be used to scroll individual layers.
HDOT SCR
parameter
SAD
SAD+1
SAD+2
P1=00H
Magnified
AP
P1=01H
SAD=SAD
Display
P1=02H
C/R
P1=03H
Virtual screen
P1=07H
P1=00H
SAD=SAD+1
Not visible
Visible
Figure: 8-7 HDOT SCR Example
Note: The response time of LCD panels changes considerably at low temperatures. Smooth scrolling
under these conditions may make the display difficult to read.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-5 Layered Display Attributes
RA8835A series incorporates a number of functions for enhanced displays using monochrome LCD
panels. It allows the display of inverse characters, half-intensity menu pads and flashing of selected
screen areas. These functions are controlled by the OVLAY and DISP ON/OFF commands.
A number of means can be used to achieve these effects, depending on the display configuration.
These are listed below. Note, however, that not all of these can be used in the one layer at the same
time.
Attribute
MX1
MX0
0
1
Reverse
1
0
1
0
1
0
1
0
0
0
1
0
0
1
1
1
Half-tone
Local flashing
Ruled line
Combined layer
display
1st layer display
IV
RAIO
IV
RAIO
ME
Yes,No
ME
Yes, No
BL
Error
BL
RL
LINE
LINE
RL
2ndt layer display
Error
LINE
LINE
Figure 8-8: Layer Synthesis
8-5-1 Inverse Display
The first layer is text, the second layer is graphics.
1. CSRW, CSDIR, MWRITE
Write is into the graphics screen at the area to be inverted.
2. OVLAY: MX0 = 1, MX1 = 0
Set the combination of the two layers to Exclusive-OR.
3. DISP ON/OFF: FP0 = FP1 = 1, FP1 = FP3 = 0.
Turn on layers 1 and 2.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-5-2 Half-tone Display
The FP parameter can be used to generate half-intensity display by flashing the display at 17 Hz.
Note that this mode of operation may cause flicker problems with certain LCD panels.
SAD1
Half-tone
SAD2
AB
AB
+
1st layer
2nd layer
Combined layer display
Figure 8-9: Half-tone Character and Graphics
8-5-2-1 Menu pad display
1. OVLAY: P1 = 00H
2. DISP ON/OFF: P1 = 34H
8-5-2-2 Graph display
To present two overlaid graphs on the screen, configure the display as for the menu bar display
and put one graph on each screen layer. The difference in contrast between the half- and fullintensity displays will make it easy to distinguish between the two graphs and help create an
attractive display.
1. OVLAY: P1 = 00H
2. DISP ON/OFF: P1 = 34H
8-5-3 Flashing Area
8-5-3-1 Small area
To flash selected characters, the MPU can alternately write the characters as character codes and
blank characters at intervals of 0.5 to 1.0 seconds.
8-5-3-1 Large area
Divide layer 1 and layer 2 into two screen blocks each, layer 2 being divided into the area to be
flashed and the remainder of the screen. Flash the layer 2 screen block at 2 Hz for the area to be
flashed and combine the layers using the OR function.
ABC
ABC
XYZ
XYZ
Figure 8-10: Localized Flashing
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-6 16 x 16-dot Graphic Display
8-6-1 Command Usage
This example shows how to display 16 x 16-pixel characters. The command sequence is as
follows:
CSRW
Set the cursor address.
CSRDIR Set the cursor auto-increment direction.
MWRITE Write to the display memory.
8-6-2 Kanji Character Display
The program for writing large characters operates as follows:
1. The microprocessor reads the character data from its ROM.
2. The microprocessor sets the display address and writes to the VRAM. The flowchart is
shown in Figure 8-13.
A0 = 0
0H
1H
2H
3H
4H
5H
6H
7H
8H
9H
AH
BH
CH
DH
EH
FH
A0 = 1
O8 O7 O6 O5 O4 O3 O2 O1 O8 O7 O6 O5 O4 O3 O2 O1
(2)
(1)
(4)
(3)
(6)
(5)
(8)
(7)
(10)
(9)
(12)
(11)
(14)
(13)
(16)
(15)
(18)
(17)
(20)
(19)
(22)
(21)
(24)
(23)
(26)
(25)
(28)
(27)
(30)
(29)
(32)
(31)
1st column
(n) shows the CG ROM
data readout order
2nd column
(6)
(4)
(2)
(19)
(17)
(15)
(13)
(11)
(9)
(7)
(5)
(3)
(1)
Data held in the microprocessor memory
2nd column
memory area
(4)
(2)
1st column
memory area
(3)
(1)
Data written into the RA8835 display memory
Figure 8-11: Graphics Address Indexing
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Figure 8-12: Graphics Bit Map
Figure 8-13: 16 x16-dot Display Flowchart
Using an external character generator ROM, and 8 x 16 pixel font can be used, allowing a 16 x 16pixel character to be displayed in two segments. The external CG ROM EPROM data format is
described in Section 7-9. This will allow the display of up to 128, 16 x 16-pixel characters. If CG
RAM is also used, 96 fixed characters and 32 bank-switchable characters can also be supported.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
8-7 Internal Character Generator Font
Character code bits 0 to 3
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
2
3
Character code bit 4 to 7
4
5
6
7
A
B
C
D
1
Figure 8-14: On-chip Character Set
Note: The shaded positions indicate characters that have the whole 6 x 8 bitmap blackened.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
9. Package Dimensions
QFP-60 pin
24.8 + 0.25
20.0 + 0.1
18.35 + 0.2
36
54
30
RA8835AP3N
1
29
Index
1.82+ 0.1
5
6
14.0 + 0.1
60
18.8 + 0.25
35
12.35 + 0.2
1.65+ 0.1
55
24
23
15
0.82 + 0.1
0.82 + 0.1
0.15 + 0.05
2.7 + 0.12
1.82 + 0.1
1.0 + 0.1
0.35 + 0.1
0 to 7 °
1.35+0.15
2.4
Figure 9-1: RA8835AP3N (Unit: mm)
T Q F P-60 pin
17.2 + 0.4
14.0 + 0.3
45
31
46
17.2+ 0.4
R A 8835A P 4N
14.0+ 0.3
11.55 + 0.3
30
Index
60
16
0.0 1
1.62 + 0.0 1
2.7+ 0.2
0.15 + 0.05
0.82 +
1.62 + 0.0 1
1
0.8+
15
0.1 5
0.35+ 0.0 5
0 to 7 o
1.6
0.8+ 0.3
Figure 9-2: RA8835AP4N (Unit: mm)
Note: Both of the RA8835AP3N and RA8835AP4N are use “lead-free” package for ROHS compliance.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10. Specifications
10-1 Absolute Maximum Ratings
Parameter
Symbol
Rating
Unit
Supply voltage range
VDD
–0.3 to 7.0
V
Input voltage range
VIN
–0.3 to VDD+ 0.3
V
Power dissipation
PD
300
mW
Operating temperature range
Topg
–20 to 75
°C
Storage temperature range
Tstg
–65 to 150
°C
Tsolder
260
°C
Soldering temperature (10 seconds).
See note 1.
Notes:
1. The humidity resistance of the flat package may be reduced if the package is immersed in solder.
Use a soldering technique that does not heatstress the package.
2. If the power supply has a high impedance, a large voltage differential can occur between the input
and supply voltages. Take appropriate care with the power supply and the layout of the supply lines.
(See Section 10-2)
3. All supply voltages are referenced to VSS = 0V.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-2 DC Characteristic
VDD = 4.5 to 5.5V, VSS = 0V, Ta = –20 to 75℃
Parameter
Symbol
Rating
Condition
Unit
Min.
Typ.
Max.
V
Supply voltage
VDD
4.5
5.0
5.5
V
Register data retention
voltage
VOH
2.0
—
6.0
V
Input leakage current
ILI
VI= VDD. See note 5.
—
0.05
2.0
μA
Output leakage current
ILO
VI= VSS. See note 5.
—
0.10
5.0
μA
Operating supply current
Iopr
See note 4.
—
3.5
8
mA
Quiescent supply current
IQ
Sleep mode,
VOSC1= V( CS )= V( RD )=
VDD
—
0.05
20.0
μA
1.0
—
18.0
MHz
1.0
—
18.0
MHz
0.5
1.0
3.0
MΩ
Oscillator frequency
fOSC
External clock frequency
fCL
Oscillator feedback
resistance
Rf
Measured at crystal,
47.5% duty cycle.
See note 6.
Input
HIGH-level input voltage
VIHC
See note 1, 2
0.5 VDD
—
VDD
V
LOW-level input voltage
VILC
See note 1, 2
VSS
—
0.2 VDD
V
VDD – 0.4
—
—
V
—
—
VSS + 0.4
V
Output
HIGH-level output voltage
VOHC
LOW-level output voltage
VOLC
IOH= 4.0 mA.
See note 1, 2
IOL= -2 mA.
See note 1, 2
Schmitt-trigger
Rising-edge threshold
voltage
Falling-edge threshold
voltage
VT+
See note 3.
0.5 VDD
0.7 VDD
0.8 VDD
V
VT–
See note 3.
0.2 VDD
0.3 VDD
0.5 VDD
V
Notes:
1. CS , RD , WR , A0, SEL1, SEL2 and TEST are inputs. VA0 to VA15, ( VRD ), ( VWR ), ( VCE ), YD,
XD0 to XD3, XSCL, LP, WF, YDIS are outputs.
2. D0 to D7, VD0 to VD7 are Bi-direction.
3. The RES are Schmitt-trigger inputs. The pulse width on RES must be at least 10*tc. Note that
pulses of more than a few seconds will cause DC voltages to be applied to the LCD panel.
4. fOSC = 10 MHz, no load (no display memory), internal character generator, 256x200 pixel display.
The operating supply current can be reduced by approximately 1mA by setting both CLO and the
display OFF.
5. VD0 to VD7 and D0 to D7 have internal feedback circuits so that if the inputs become highimpedance, the input state immediately prior to that is held. Because of the feedback circuit, input
current flow occurs when the inputs are in an intermediate state.
6. Because the oscillator circuit input bias current is in the order of uA, design the printed circuit board
so as to reduce leakage currents.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
VDD = 2.7 to 4.5V, VSS = 0V, Ta = –20 to 75℃
Parameter
Symbol
Rating
Condition
Unit
Min.
Typ.
Max.
V
Supply voltage
Register data retention
voltage
Input leakage current
VDD
2.7
3.3
4.5
V
VOH
2.0
—
6.0
V
ILI
VI = VDD. See note 5.
—
0.05
2.0
μA
Output leakage current
ILO
—
0.10
5.0
μA
Operating supply current
Iopr
VI = VSS. See note 5.
VDD = 3.5 V.
See note 4.
See note 4.
Sleep mode,
VOSC1= V( CS )= V( RD )=
VDD
—
3.5
—
—
—
7.0
—
0.05
20.0
μA
1.0
—
16.0
MHz
1.0
—
16.0
MHz
0.7
—
3.0
MΩ
Quiescent supply current
IQ
mA
Oscillator frequency
fOSC
External clock frequency
Oscillator feedback
resistance
Input
fCL
HIGH-level input voltage
VIHC
See note 1, 2
0.5 VDD
—
VDD
V
LOW-level input voltage
VILC
See note 1, 2
VSS
—
0.2 VDD
V
VDD – 0.4
—
—
V
—
—
VSS + 0.4
V
Rf
Measured at crystal,
47.5% duty cycle.
See note 6.
Output
IOH= 4.0 mA.
See note 1, 2
IOL= -2 mA.
See note 1, 2
HIGH-level output voltage
VOHC
LOW-level output voltage
VOLC
Schmitt-trigger
Rising-edge threshold
voltage
Falling-edge threshold
voltage
VT+
See note 3.
0.5 VDD
0.7 VDD
0.8 VDD
V
VT–
See note 3.
0.2 VDD
0.3 VDD
0.5 VDD
V
Notes
1. CS , RD , WR , A0, SEL1, SEL2 and TEST are inputs. VA0 to VA15, ( VRD ), ( VWR ), ( VCE ), YD,
XD0 to XD3, XSCL, LP, WF, YDIS are outputs.
2. D0 to D7, VD0 to VD7 are Bi-direction pins.
3. The RES are Schmitt-trigger inputs. The pulse width on ( RES ) must be at least 10*tc. Note that
pulses of more than a few seconds will cause DC voltages to be applied to the LCD panel.
4. fOSC = 10 MHz, no load (no display memory), internal character generator, 256x200 pixel display.
The operating supply current can be reduced by approximately 1mA by setting both CLO and the
display OFF.
5. VD0 to VD7 and D0 to D7 have internal feedback circuits so that if the inputs become highimpedance, the input state immediately prior to that is held. Because of the feedback circuit, input
current flow occurs when the inputs are in an intermediate state.
6. Because the oscillator circuit input bias current is in the order of μA, design the printed circuit board
so as to reduce leakage currents.
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3 Timing Diagrams
10-3-1 8080 Family Interface Timing
Ta = –20 to 75°C
Signal
Symbol
A0, CS
tAH8
VDD = 4.5 to 5.5V
Parameter
Address hold time
VDD = 2.7 to 4.5V
Min.
Max.
Min.
Max.
10
—
10
—
Unit
ns
tAW8
Address setup time
0
—
0
—
ns
WR ,
tCYC8
System cycle time
note.
—
note.
—
ns
RD
tCC
Strobe pulse width
120
—
150
—
ns
tDS8
Data setup time
120
—
120
—
ns
tDH8
Data hold time
5
RD access time
Output disable time
—
50
5
—
—
—
80
ns
10
50
10
55
ns
D0 to D7
tACC8
tOH8
Condition
CL =
100pF
ns
Note: For memory control and system control commands:
tCYC8 = 2tC + tCC + tCEA + 75 > tACV + 245
For all other commands:
tCYC8 = 4tC + tCC + 30
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3-2 6800 Family Interface Timing
E
tCYC6
tAW6
tEW
R/W
tAH6
A0, CS
tDH6
tDS6
D0 to D7
(write)
tACC6
tOH6
D0 to D7
(Read)
Ta = –20 to 75°C
Signal
Symbol
A0, CS ,
R/( W )
D0 to D7
E
VDD = 4.5 to 5.5V
Parameter
VDD = 2.7 to 4.5V
Unit
Min.
Max.
Min.
Max.
System cycle time
note.
—
note.
—
ns
tAW6
Address setup time
0
—
10
—
ns
tAH6
Address hold time
0
—
0
—
ns
tDS6
Data setup time
100
—
120
—
ns
tCYC6
tDH6
Data hold time
0
—
0
—
ns
tOH6
Output disable time
10
50
10
75
ns
tACC6
Access time
—
85
—
130
ns
120
—
150
—
ns
tEW
Enable pulse width
Condition
CL = 100
pF
Note: For memory control and system control commands:
tCYC6 = 2tC + tEW + tCEA + 75 > tACV + 245
For all other commands:
tCYC6 = 4tC + tEW + 30
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3-3 Display Memory Read Timing
EXT￠0
tC
tCE
tW
tW
VCE
VA0 to VA15
tCYR
tASC
tAHC
VR / W
tRCH
tCEA
tRCS
tCE3
tOH2
tACV
VD0 to VD7
Ta = –20 to 75℃
Signal
Symbol
EXT Φ0
tC
tW
VCE
tCE
tCYR
VA0 to
VA15
tASC
VDD = 4.5 to 5.5V
Parameter
Clock period
VCE HIGH-level
pulse width
VCE LOW-level
pulse width
Read cycle time
Address setup time
to falling edge of
VDD = 2.7 to 4.5V
Unit
Min.
Max.
Min.
Max.
55.5
—
62.5
—
ns
tC – 50
—
tC – 50
—
ns
2tC – 30
—
2 tC – 30
—
ns
3tC
—
3tC
—
ns
tC – 70
—
tC – 100
—
ns
2 tC – 30
—
2tC – 40
—
ns
Condition
VCE
tAHC
Address hold time
from falling edge of
VCE
tRCS
VRD
tRCH
Read cycle setup
time to falling edge
of VCE
Read cycle hold time
from rising edge of
CL = 100
pF
tC – 45
—
tC – 60
—
ns
0.5tC
—
0.5tC
—
ns
—
—
3tC – 115
2tC – 90
Ns
Ns
VCE
tACV
tCEA
VD0 to
VD7
tOH2
tCE3
RAiO TECHNOLOGY INC.
Address access time
VCE access time
Output data hold
time
VCE to data off
time
83/88
—
—
3tC – 100
2tC – 80
0
—
0
—
ns
0
—
0
—
ns
www.raio.com.tw
RA8835A
Version 1.3
Dot Matrix LCD Controller
10.3-4 Display Memory Write Timing
tC
EXT￠ O
VA0 to VA15
tW
VCE
t CE
t ASC
t CA
t AHC
t AS
t W SC
tW HC
t AH2
VR/W
t DSC
t DH2
t DHC
VD0 to VD7
Ta = –20 to 75℃
Signal
Symbol
EXT Φ0
tC
Clock period
tW
VCE HIGH-level
pulse width
VCE
tCE
tCYW
tAHC
tASC
VA0 to
VA15
tCA
tAS
tAH2
Parameter
VCE LOW-level
pulse width
Write cycle time
Address hold time
from falling edge of
VCE
VDD = 4.5 to 5.5V
Min.
Max.
55.5
—
VDD = 2.7 to 4.5V
Min.
Max.
62.5
—
tC – 50
—
tC – 50
—
ns
2tC – 30
—
2tC – 30
—
ns
3tC
—
3tC
—
ns
2tC – 30
—
2tC – 40
—
ns
tC – 70
—
tC – 110
—
ns
0
—
0
—
ns
0
—
0
—
ns
10
—
10
—
ns
tC – 80
—
tC – 115
—
ns
2tC – 20
—
2tC – 20
—
ns
tC – 85
—
tC – 125
—
ns
2tC – 30
—
2tC – 30
—
ns
5
50
5
50
ns
Address setup time to
falling edge of VCE
Address hold time
from rising edge of
Unit
Condition
ns
VCE
Address setup time to
falling edge of VWR
Address hold time
from rising edge of
CL = 100
pF
VWR
tWSC
VWR
tWHC
VD0 to
VD7
Write setup time to
falling edge of VCE
Write hold time from
tDSC
falling edge of VCE
Data input setup time
to falling edge of
tDHC
Data input hold time
from falling edge of
tDH2
VCE
VCE
Data hold time from
rising edge of VWR
Note: VD0 to VD7 are latching input/outputs. While the bus is high impedance, VD0 to VD7 retain
the write data until the data read from the memory is placed on the bus.
RAiO TECHNOLOGY INC.
84/88
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3-5 Sleep In Command Timing
VCE
WR
(Command input)
SYSTEM SET write
SLEEP IN write
tWRL
tWRD
YDIS
Ta = –20 to 75°C
Signal
Symbol
Parameter
VDD = 4.5 to 5.5V
Min.
Max.
VDD = 2.7 to 4.5V
Min.
Max.
Unit
tWRD
VCE falling-edge
delay time
note 1.
—
note 1.
—
ns
tWRL
YDIS falling-edge
delay time
—
note 2.
—
note 2.
ns
WR
Condition
CL = 100
pF
Notes:
1. tWRD = 18tC + tOSS + 40 (tOSS is the time delay from the sleep state until stable operation)
2. tWRL = 36tC x [TC/R] x [L/F] + 70
RAiO TECHNOLOGY INC.
85/88
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3-6 External Oscillator Signal Timing
tRCL
tFCL
tWH
EXT￠0
tWL
tC
Ta = –20 to 75℃
Signal
Symbol
tRCL
tFCL
EXT Φ0
tWH
tWL
tC
VDD = 4.5 to 5.5V
Min.
Max.
Parameter
External clock rise
time
External clock fall
time
External clock
HIGH-level pulse
width
External clock
LOW-level pulse
width
VDD = 2.7 to 4.5V
Min.
Max.
Unit
—
10
—
10
ns
—
10
—
10
ns
note 1.
note 2.
note 1.
note 2.
ns
note 1.
note 2.
note 1.
note 2.
ns
55.5
—
62.5
—
ns
External clock period
Condition
Notes:
475
< t WH , t WL
1000
525
− t FCL ) ×
> t WH , t WL
1000
1. ( t C − t RCL − t FCL ) ×
2. ( t C − t RCL
RAiO TECHNOLOGY INC.
86/88
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RA8835A
Version 1.3
Dot Matrix LCD Controller
10-3-7 LCD Output Timing
The following characteristics are for a 1/64 duty cycle.
62
Row
LP
63
64
1
2
3
4
60
61 62
63
64
1frame time
YD
WF
WF
1lime time
ROW 64
Row 1
Row 2
LP
XSCL
XD0 to XD3 (14)(15)(16)
(1)
(15)(16)(1)(2)(3)
(15) (16)
(1)
tcx
twx
tr
XSCL
tf
tDS
tDH
tLS
XD0 to XD3
tLD
tWL
LP
tDHY
tDF
WF(B)
YD
RAiO TECHNOLOGY INC.
87/88
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RA8835A
Version 1.3
Dot Matrix LCD Controller
Ta = –20 to 75℃
Signal
Symbol
XSCL
VDD = 2.7 to 4.5V
Min.
Max.
Unit
Rise time
—
30
—
40
ns
Fall time
—
30
—
40
ns
Shift clock cycle time
2tC
—
2tC
—
ns
tC – 20
—
ns
tCX
tC – 20
—
tDH
XSCL clock pulse
width
X data hold time
2tC – 50
—
2tC – 50
—
ns
tDS
X data setup time
2tC – 100
—
2tC – 105
—
ns
tC – 20
—
tC – 20
—
ns
2tC – 10
—
2tC – 10
—
ns
tC – 20
—
ns
tWL
Latch data setup
time
LP pulse width
WF
tDF
LP delay time from
XSCL
Permitted WF delay
YD
tDHY
Y data hold time
tLD
RAiO TECHNOLOGY INC.
Max.
tf
tLS
LP
Min.
tr
tWX
XD0 to
XD3
VDD = 4.5 to 5.5V
Parameter
tC – 20
—
tC – 20
tc+30
tC – 20
tc+30
ns
2tC – 20
—
2tC – 20
—
ns
88/88
Condition
CL =
100 pF
www.raio.com.tw