ApplicationNote
InterfacingtoaGraphicsModulewithaToshiba
T6963CController
Introduction:
TheToshibaT6963CLCDcontrollerisoneofthemostpopularcontrollersforuseinsmallgraphics
displays.ForthisreasonitisusedinanumberofLCDmodulesfrom128x128to 240x128 pixels.
Thisclassofmoduleismostcommonlyusedtodisplayamixtureoftextand graphics in samall
devicesandinstruments.Itisusuallyinterfaceddirectlywithanembedded8-bit microprocessor.
Thisapplicationnotedescribestheuseofthiscontrollerwithanumberof graphics modules.
Theexampleusedhereisbasedonan8-bitIntelI8051microcontroller but applies to almost any
micro-controller.
FunctionalDescription:
TheT6963Cusesasimple8-bitdatabustotransferallinstructionsanddatatoandfromthe
display.Afterpowerisappliedahardwareresetisissued.Thecontrollermustthenbeinitialized
withaseriesofcommandstosetupthevariousmodesandoptionsavailabletotheuser.Once
initializedthedisplayisreadytoacceptthedatatobedisplayed.Thisdatacanbeintheformof
bit-mappedgraphicaldataortextdatainpseudoASCIIformat.Theinternalcharactergeneratoris
biasedat-20h.whichmeanstheusermustsubtract20hfromtheASCIIcodebeforesendingitto
thedisplay.
Inthebit-mappedmodeeachbyteofdatarepresents8pixelsonthedisplay.SeeFigure#1.Text
datacanbewritteninpseudoASCIIformatandwillbedisplayedasa5x7dotcharacter.The
graphicalandtextdataarewrittentoseparate,userassigned,areas,orpages,inthedisplayRAM
withinthedisplaymodule.Theusercanthenchooseoneofthreewaystomixthetextand
graphicspagesonthedisplayorthetextorgraphicspagecanbedisplayedalone.
D0
ST
1BYTE
D1
D3 D4 D5
D2
TH
17BYTE
Figure#1Memorymapofa128x128display
D7 D0 D1
D6
ND
2BYTE
Schematic:
The80C51microprocessorisconnectedtotheLCDcontrollerchipviaparallelI/Oportsinthis
example.Itcouldalsobeconnectedtotheprocessor'sdatabusandbemappedintothe
processor'sdatamemoryarea.Seefigure2.
Page1
ApplicationNote
1N4148
33pF
16.00mHz
33pF
+5v
+
10k
1uF
X1
X2
RST
80C51
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P3.0
P3.1
P3.2
P3.3
240x64LCDDISPLAY
D0
D1
D2
D3
D4
D5
D6
D7
WR
RD
CE
CD
RESET
+5v
V
FS
V
FG
DD
V
L
SS
-15V
Figure2Schematicdiagram
20K
Software:
Thesampleprogramhereiswrittenin8051assemblylanguageandisdesignedtoworkwiththe
hardwareshowninFigure2.Itisbasedona240x64displaybutisapplicabletoanyLCD with the
T6963Ccontroller.
Theprogramfirstresetsthedisplay.Thisresetmustlastaminimumof2µS.Itthensendsaseriesof
commandbytesandparameterstotheLCDcontrollertoinitializeit.TheT6963Crequiresthatthe
parameters,ifany,aresentinthedatamodeandmustprecedethecommandbyte,whichissentin
thecommandmode.
Thecontrollerisinitializedwiththegraphicspageat0000-077fh.Thisis1920byteswhichwill
accommodateafullscreenofdata.Notextisdisplayedinthisexamplebutthecontrolleris
initializedfortextoperationtoillustratetheprocess.Thetextpagestartsimmediatelyfollowingthe
graphicspageatlocation0780h.
TheFS(FontSelect)lineissettoazerointhisexamplewhichwillplacethe5x7pixelcharacterina
8x8pixelfield.Thiswillproduce30charactersperlinewith8linesperdisplay().Thetotal
numberofcharacters possibleinthismodeis240.
AoneontheFSlinewillproducean6x8pixel
240
8
=30
fieldforeachcharacter.
Afterinitializationthecontrollerissetintheautowritemodeandthedisplayisfilledwithabit-
mappedgraphic.
Thecodeexampleisnotwrittentobeefficientbuttobeassimpleaspossible.
tofollow
Page2
ApplicationNote
SoftwareFlowchart:
MAINPROGRAMLOOP
START:
INITIALIZE
T6963C
DISPLAY
BITMAP
END
WRITEA
COMMANDBYTE
WRITEC:
WRITEA
DATABYTE
WRITED:
SENDABLOCKOFDATA
TOTHEDISPLAY
MSGD:
GETBYTE
FROMTABLE
CALL
WRITED
INC.TABLE
POINTER
STATUSCHECK
STATUS:
RETURN
COMMAND
PARAMETERS
SETCOUNTER
FROMTABLE
YES
SENDA
WITH
MSGC:
TO2
GETBYTE
END
BYTE?
NO
CALL
WRITED
STATUS
OK?
YES
SETC/DTO1 SETC/DTO0
DATATOP1
WRLOW
WRHIGH
RETURN
NO
STATUS
OK?
YES
NO
SETC/DTO1
RDLOW
READBYTE
RDHIGH
STATUS
OK?
YES
RETURN
NO
INC.TABLE
POINTER
DECREMENT
COUNTER
CNT=
0?
YES
GETCOMM.
FROMTABLE
CALL
WRITEC
NO
Page3
ApplicationNote
Initialization:
BeforetheLCDcontrollercanacceptordisplaydataortextitmustbeinitialized.Thisisusually
doneimmediatelyafterthesystemispoweredup.Thefollowingchartliststheinitialization
commandsandtheparametersthataccompanythemalongwithabriefexplanationofthefunction
ofeach.Whereaparameterisdifferentforadisplaythatdiffersinresolutionfromthe240x64
example,thealternatevaluesarealsolisted.
Initializationbytes:
COMMAND CODE PARAMETERS* FUNCTION
TEXTHOMEADDRESS 40h 80h,07h
1eh,00h
(240x128,240x64)
TEXTAREA
41h
14h,00h
(160x128)
10h,00h
(128x128)
STARTOFTHETEXTSTORAGEAREAINDISPLAYRAM
0780h
LINELENGTHINCHARACTERS=30=1ehFORAN
8BITCHARACTERCELL(FS=0).(28hFORFS=1)
LINELENGTHINCHARACTERS=20=14hFORAN
8BITCHARACTERCELL(FS=0).(1ahFORFS=1)
LINELENGTHINCHARACTERS=16=10hFORAN
8BITCHARACTERCELL(FS=0).(15hFORFS=1)
240
8
160
8
128
8
GRAPHICHOMEADDRESS 42h 00h,00h
1eh,00h
(240x128,240x64)
GRAPHICAREA
43h
14h,00h
(160x128)
10h,00h
(128x128)
MODESET
ADDRESSPOINTERSET
DISPLAYMODESET
*ADDRESSESAREFORMATTEDAS[LSB,MSB]
81h
24h
98h
00h,00h
Displayedimage:
STARTOFTHEGRAPHICSSTORAGEAREAINDISPLAY
RAM0000h
LINELENGTHINPIXELS=30=1eh
LINELENGTHINPIXELS=20=14h
LINELENGTHINPIXELS=16=10h
240
8
160
8
128
8
"EXOR"TEXTMODE
LOCATIONOFNEXTDATAWRITE(ORREAD)
INTHISCASETHEBEGINNINGOFTHEGRAPHICSAREA
TEXTOFF,GRAPHICSON
Page4
ApplicationNote
Software:
$mod51
;**************************************************
;**
;*T6963ApplicationNoteV1.0*
;**
;**************************************************
;Theprocessorclockspeedis16MHz.
;Cycletimeis.750mS.
;Demosoftwaretodisplayabit-mapped
;graphicona240x64graphicsdisplay
;withaT6963CLCDcontroller.
org000h
ljmpstart;programstart
org100h
start:
;InitializetheT6963C
clrp3.3;hardwarereset
nop
nop
setbp3.3
movdptr,#msgi1;initializationbytes
lcallmsgc
;Startofregularprogram
;MSGDsendsthedatapointedtoby
;theDPTRtothegraphicsmodule.
msgd:
msgd1:
;WRITECsendsthebyteinR1toa
;graphicsmoduleasacommand.
writec:
writec1:
;WRITEDsendsthebyteinR1tothe
;graphicsmoduleasdata.
incdptr
djnzr0,msgc2
clra
movca,@a+dptr;getcommand
movr1,a
lcallwritec;sendcommand
sjmpmsgc;nextcommand
clra
movca,@a+dptr;getbyte
cjnea,#0a1h,msgd1;done?
ret
movr1,a
lcallwrited;senddata
incdptr
sjmpmsgd
lcallstatus;displayready?
setbp3.2;c/d=1
movp1,r1;getdata
clrp3.0;strobeit
setbp3.0
ret
;Displaygraphic
movdptr,#msgi2;setautomode
lcallmsgc
movdptr,#msg1;displaygraphic
lcallmsgd
sjmp$
;*************************************************
;SUBROUTINES
;MSGCsendsthedatapointedtoby
;theDPTRtothegraphicsmodule
;asaseriesofcommandswith
;twoparameterseach.
msgc:
movr0,#2;#ofdatabytes
msgc2:
clra
movca,@a+dptr;getbyte
cjnea,#0a1h,msgc3;done?
ret
msgc3:movr1,a
lcallwrited;sendit
writed:
lcallstatus;displayready?
clrp3.0;c/d=0
sjmpwritec1
;STATUSchecktoseethatthegraphic
;displayisready.Itwon'treturn
;untilitis.
status:
setbp3.2;c/d=1
movp1,#0ffh;P1toinput
movr3,#0bh;statusbitsmask
stat1:
clrp3.1;readit
mova,p1
setbp3.1
anla,r3;statusOK?
clrc
subba,r3
jnzstat1
ret
Page5
ApplicationNote
;************************************************
;TABLESANDDATA
;Initializationbytesfor240x64
msgi1:
db80h,07h,40h;texthomeaddress
db1eh,00,41h;textarea
db00,00,42h;graphichomeaddress
db1eh,00,43h;graphicarea
db00,00,81h;modeset
db00,00,24h;addresspointerset
db00,00,98h;displaymodeset
db0a1h
msgi2:
;240x64Bitmapgraphicdata
;Onlythefirst8bytesareshownhere
;Therealgraphicconsistsof1920bytes
;ofbinarydata.
msg1:
db00,00,0b0h;automode
db0a1h
db00h,00h,00h,00h,00h,00h,00h,00h
db0a1h
end
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