MC144032B6WCB-SPTLY Midas, MC144032B6WCB-SPTLY Datasheet - Page 8

• Manufacturer Part Number: MC144032B6WCB-SPTLY
• Description: LCD, 144X32, STN, Y/GN B/L, CHINESE; Backlighting Colour: Yellow Green; LCD Display Type: STN; Pixel Size (H x W): 0....
• Manufacturer: Midas

Busy Flag (BF)
Internal operation is in progress when BF="I", ST7920 is in busy state. No new instruction will
be accepted until BF="0". MPU must check BF to determine whether the internal operation is
finished and new instruction can be sent.
Addr e ss c ounte r (AC)
Ad d ress coun te r( AC )is us ed for ad dress po in ter o f DD R AM/C GR AM/IR AM/GD R AM.
(AC ) ca n b e se t b y i ns tru cti on an d a fte r da ta re ad o r w ri te to the m emo ries (AC ) wi ll
i n crease o r d ecre ase b y 1 a cco rdi ng to the se tti ng i n "en try mo de se t". Wh en
R S="0 " an d R W= "1 " a nd E="1 " the va lu e o f ( AC ) wil l o u tp u t to D B6 ~D B0 .
16x16 character generation ROM (CGROM) and 8x16 half height ROM ( HCGROM )
ST7920 provides character generation ROM supporting 8192 16 x 16 character fonts and 126 8 x 16
alphanumeric characters. It is easy to support multi languages application such as Chinese and English.
Two consecutive bytes are used to specify one 16x16 character or two 8x16 half-height characters.
Character codes are written into DDRAM and the corresponding fonts are mapped from CGROM or
HCGROM to the display drivers.
Character generation RAM (CGRAM)
ST7920 provides RAM to support user-defined fonts. Four sets of 16x16 bit map area are available. These
user-defined fonts are displayed the same ways as CGROM fonts through writing character cod data to
DDRAM
6. Function Description
Fun ction Descrip tion：
Sys tem i n terfa ce
ST7920 suppo rts 3 kin ds o f b us in te rface to MPU . 8 b its paralle l, 4 bi ts pa ral lel and
clo ck s ynchro ni ze d serial in terface . Pa rall el i n terfa ce is selected b y PSB="I" a nd se rial
in terfa ce b y PSB="0". 8 b it / 4 bi t i nterfa ce is selecte d b y fun ction s et ins tru ction DL
bi t.
Two 8 b it re gisters (da ta regis te r DR , instru ction reg iste r IR ) a re used in ST79 20 's
w ri te and read op era tion . Da ta Re giste r (D R) can access DD R AM/C GR AM/GDR AM
an d IR AM's da ta th roug h the add ress po in ter impl emented b yAdd ress C oun te r (AC).
Ins tru ction Regis ter (IR) s to res th e instru ction b y MPU to ST7920 .
4 modes of read/write operation specified by RS and RW：
L
L
H
H
RS
L
H
L
H
RW
MPU write instruction to instruction register (IR)
MPU read busy flag (BF) and address counter (AC)
MPU write data to data register (DR)
MPU read data from data register (DR)
description