Chapter 10 Glass Bliss

1
Chapter 10 Glass Bliss

• Using the Parallel Master Port to communicate
  with Alphanumeric LCD displays

2
Alphanumeric LCD Modules
3
HD44780 Instruction Set
Instruction Code Description /
Execution time RS R/W DB7 DB6 DB5 DB4 DB3 DB2 D
B1 DB0 Clear display 0 0 0 0 0 0 0 0 0 1 Clears
display and returns cursor to the
home position (address 0). 1.64mS Curs
or home 0 0 0 0 0 0 0 0 1 Returns cursor to
home position (address 0). Also
returns display being shifted to the original
position. DDRAM contents remains
unchanged. 1.64mS Entry mode
set 0 0 0 0 0 0 0 1 I/D S Sets cursor move
direction (I/D), specifies to shift
the display (S). These operations
are performed during data
read/write. 40uS Display On/Off
0 0 0 0 0 0 1 D C B Sets On/Off of all display
(D), cursor On/Off (C) and blink of
cursor position character (B). 40uS
Cursor/display shift 0 0 0 0 0 1 S/C R/L Sets
cursor-move or display-shift (S/C), shift
direction (R/L). DDRAM contents
remains unchanged. 40uS Function
set 0 0 0 0 1 DL N F Sets interface data
length (DL), number of display line
(N) and character font(F). 40uS Set CGRAM
addr 0 0 0 1 CGRAM address Sets the CGRAM
address. CGRAM data is sent and
received after this setting. 40uS Set DDRAM
addr 0 0 1 DDRAM address Sets the DDRAM
address. DDRAM data is sent and
received after this setting. 40uS Read busy-flag
and address ctr 0 1 BF CGRAM / DDRAM
address Reads Busy-flag (BF) indicating
internal operation is being
performed and reads CGRAM or DDRAM
address counter contents (depending
on previous instruction). 0uS Write
to CGRAM 1 0 write data Writes data to
CGRAM or DDRAM. 40uS (or DDRAM) Read CGRAM
1 1 read data Reads data from CGRAM or
DDRAM. 40uS (or DDRAM)
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HD44780 Instruction Set (cont.)
Bit name Setting / Status I/D 0 Decrement
cursor position 1 Increment cursor
position S 0 No display shift 1 Display
shift D 0 Display off 1 Display on C 0
Cursor off 1 Cursor on B 0 Cursor blink
off 1 Cursor blink on S/C 0 Move cursor 1
Shift display R/L 0 Shift left 1 Shift
right DL 0 4-bit interface 1 8-bit
interface N 0 1/8 or 1/11 Duty (1 line) 1
1/16 Duty (2 lines) F 0 5x7 dots 1 5x10
dots BF 0 Can accept instruction 1
Internal operation in progress
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Character Generator Table
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Parallel Master Port
7
PMCON
PMCON Register 20-1 (DS61143)
8
LCD Initialization
define LCDDATA 1 // RS 1 access
data register define LCDCMD 0 // RS
0 access command register define PMDATA
PMDIN1 // PMP data buffer void LCDinit(
void) // PMP initialization PMCON
0x83BF // Enable the PMP, long waits
PMMODE 0x3FF // Master Mode 1
PMPEN 0x0001 // PMA0 enabled  
PMADDR LCDCMD // command register
(ADDR 0) PMDATA 0x38 // set
8-bit interface, 2 lines, 5x7 TMR1 0
while( TMR1lt8) // 8 x 6us 48us PMDATA
0x0c // ON, no cursor, no blink
TMR1 0 while( TMR1lt8) // 8 x 6us 48us
PMDATA 0x01 // clear display
TMR1 0 while( TMR1lt300) // 300 x 6us 1.8ms
PMDATA 0x06 // increment
cursor, no shift TMR1 0 while( TMR1lt300)
// 300 x 6us 1.8ms // LCDinit
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Reading the LCD
char readLCD( int addr) int dummy
while( PMMODEbits.BUSY) // wait for PMP to be
available PMADDR addr //
select the command address dummy PMDATA
// init read cycle, dummy read
while( PMMODEbits.BUSY) // wait for PMP to be
available return( PMDATA) // read
the status register // readLCD define
busyLCD() readLCD( LCDCMD) 0x80 define
addrLCD() readLCD( LCDCMD) 0x7F define
getLCD() readLCD( LCDDATA)
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Writing to the LCD
void writeLCD( int addr, char c) while(
busyLCD()) while( PMMODEbits.BUSY) //
wait for PMP to be available PMADDR addr
PMDATA c // writeLCD define busyLCD()
readLCD( LCDCMD) 0x80 define addrLCD()
readLCD( LCDCMD) 0x7F define getLCD()
readLCD( LCDDATA)
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Extending the Include Search Path
12
LCD Control Using the peripheral library
void initLCD( void) // PMP initialization
mPMPOpen( PMP_ON PMP_READ_WRITE_EN 3,
PMP_DATA_BUS_8 PMP_MODE_MASTER1
PMP_WAIT_BEG_4 PMP_WAIT_MID_15
PMP_WAIT_END_4, 0x0001,
// only PMA0 enabled
PMP_INT_OFF) // no interrupts used
// wait for gt30ms Delayms( 30)
//initiate the HD44780 display 8-bit init
sequence PMPSetAddress( LCDCMD) //
select command register PMPMasterWrite(
0x38) // 8-bit int, 2 lines, 5x7
Delayms( 1) // gt 48 us
PMPMasterWrite( 0x0c) // ON, no cursor, no
blink Delayms( 1) // gt 48 us
PMPMasterWrite( 0x01) // clear
display Delayms( 2) // gt
1.6ms PMPMasterWrite( 0x06) //
increment cursor, no shift Delayms( 2)
// gt 1.6ms // initLCD
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LCD Control Using the peripheral library
char readLCD( int addr) PMPSetAddress(
addr) // select register
mPMPMasterReadByte() // initiate read
sequence return mPMPMasterReadByte()// read
actual data // readLCD     void writeLCD( int
addr, char c) while( busyLCD())
PMPSetAddress( addr) // select register
PMPMasterWrite( c) // initiate write
sequence // writeLCD
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putsLCD()
void putsLCD( char s) char c
while( s) switch (s)
case '\n' // point to second
line setLCDC( 0x40)
break case '\r' // home, point
to first line setLCDC( 0)
break case '\t' // advance
next tab (8) positions c
addrLCD() while( c 7)
putLCD( ' ')
c if ( c gt 15) //
if necessary move to second line
setLCDC( 0x40) break
default // print character
putLCD( s) break
//switch s //while
//putsLCD
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Advanced LCD Control
define setLCDG( a) writeLCD( LCDCMD, (a 0x3F)
0x40)
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Progress Bar
void newBarTip( int i, int width) char bar
int pos // save cursor position
while( busyLCD()) pos addrLCD()   //
generate a new character at position i // set
the data pointer to the LCD CGRAM buffer
setLCDG( i8) // as a horizontal bar
(0-4)x thick moving left to right // 7 pixel
tall if ( width gt 4) width 0
else width 4 - width
for( bar0xff width gt 0 width--)
barltlt1 // bar gtgt 1 if right to
left   // fill each row (8) with the same
pattern putLCD( bar) putLCD( bar)
putLCD( bar) putLCD( bar) putLCD(
bar) putLCD( bar) putLCD( bar)
putLCD( bar) // restore
cursor position setLCDC( pos) //
newBarTip  
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Progress Bar (cont.)
void drawProgressBar( int index, int imax, int
size) // index is the current progress value
// imax is the maximum value // size is
the number of character positions available
int i // scale the input values in the
available space int width index (size5)
/ imax // generate a character to
represent the tip newBarTip( TIP, width 5)
// user defined character 0   // draw a
bar of solid blocks for ( iwidth/5 igt0
i--) putLCD( BRICK) // filled
block character   // draw the tip of the bar
putLCD( TIP) // use character
0 // drawProgressBar