'
' Example program for using MAX7219 8x 7-segment LED display modules
'
option explicit
option default integer
'
const CS=24 'latch pin for display
'
' MAX7219 Registers
const decode=&H09
const intens=&H0A
const scanlim=&H0B
const shutdwn =&H0C
const digtest=&H0F
' MAX7219 Data Constants
const Set_Off = 0
const Set_On = 1
const No_Digits = 7 ' Scan limit for digits 0 to 3 = 4
const Dec_Digits = 15 ' decode digits 0 to 3 according to "code B"
const Init_Inten = 8 ' 0 (=1/32 PWM on time) to 15 (=31/32 PWM on time)
const DigBlank = 15 '"Code B" value to black a digit
const DecimPnt = 128 ' Add this value to a digit value/code when we want the decimal point illuminated
const Decimal = 10
const Hexadec = 16
' Array of segment codes for numbers and letter approximations
data &H7E, &H30, &H6D, &H79, &H33, &H5B, &H5F, &H70, &H7F, &H7B, &H77, &H1F, &H4E, &H3D, &H4F, &H47, &H5E, &H37
data &H30, &H3C, &H2F, &H0E, &H55, &H15, &H1D, &H67, &H73, &H05, &H5B, &H0F, &H3E, &H1C, &H5C, &H49, &H3B, &H6D
'
INIT:
dim ch(36),i
for i= 0 to 35
read ch(i)
next i
initmax7219
Main:
display("Hello OK") 'test uppercase conversion
pause 3000
display("...HELLO") 'test leading fullstops
pause 3000
display("Hello world, Hello world, Hello world, Hello world") 'test too long string
pause 3000
display(str$(65536,8)) 'Test simple numebr output
pause 3000
display(str$(14.88,6,2)) 'test float output
pause 3000
display(hex$(1234567890,8)) 'test hex output
pause 3000
display("1.2.3.4.5.6.7.8.") 'test max valid string length
end
'
sub initmax7219
setpin cs, dout
pin(cs)=0
SPI OPEN 1000000,3,16
sendcommand(decode,0) 'we want straight access to the elements of the LEDs
sendcommand(intens,Init_Inten)
sendcommand(scanlim,No_Digits)
sendcommand(Shutdwn, Set_on)
sendcommand(DigTest, Set_Off)
clearMAX7219
end sub
'
sub sendcommand(register, command)
local i = SPI((register<<8)+command)
pulse CS,0.005
end sub
'
sub display(textin$)
local text$
text$=ucase$(textin$)
local i,j,k=0,buff(16)
for i=0 to 7
buff(i)=0
endif
for i=1 to len(text$)
j=asc(mid$(text$,i,1))
if j=32 then
buff(k)=0
else
if j=46 then 'handle the special case of fullstops/decimal points
if k<>0 then
if (buff(k-1) and 128)=0 then
k=k-1
buff(k)=buff(k) or 128 'set the decimal point on the previous character
else
buff(k)=128
endif
else
buff(k)=128
endif
else
j=j-48 'convert ascii
if j>9 then j=j-7
if j>=0 and j<=35 then
buff(k)=ch(j)
else
buff(k)=0
endif
endif
endif
k=k+1
if k>=10 then exit for
next i
for i=1 to 8
sendcommand(i,buff(8-i))
next i
end sub
'
sub clearMAX7219
for i=1 to 8
sendcommand(i,0) 'blank the display
next i
end sub
'