Digital touch Screen Combination lock

[richard]

5 dec = 5 hex = bin 101 , numbers are just numbers
all digital computers to date are binary devices and that's all they can cope with
programs like pbp C mpasm ...... allow humans to specify numbers in any form we are comfortable with

generally we have conventions to remove number base confusion
eg 5 = $5 = 0x05 =%00000101 = 0b00000101= %101 =$05 = %000000000000000101 . the chip only ever sees the binary version

[astanapane]

What i mean is if that numbers corresponds to 8 LATx for example for portA

For example if we write

LATA = 5

is that number correspond to binary 8 bit LATA.x , so that number 5 will write only to %00000101 which is the LATA.0 and LATA.2

Can we write a number then to only one LATA.x

for example can we write

LATA.0 = 5

What that number will represent for the LATA.0

based on the schematic logic gates receive only 0s or 1s. So LATA.x could only get 0s or 1s. Is that right?

[richard]

LATA = 5
replaces the entire contents of lata latch with 5

LATA.0 = 5

is a syntax error a bit can only be 0 or 1

lata.0 is bit 0 of the lata latch

[richard]

lesson 4 bit manipulation need 8 leds attached to porta:0-7

These four routines [below] march a single lit led across the eight pins of porta from a0 to a7 when inserted in the shell provided.
try each, which is the best do you think
one of them could have "issues" @ 64mhz. which one? and why?


can you reverse the direction of the march for each one ?
can you light up the leds and march a single unlit led across the eight pins of porta from a0 to a7 ?

i.
PORTA.0=1
WHILE PORTA
PAUSE 200
PORTA=PORTA<<1
WEND
ii.
PORTA.0=1
WHILE PORTA
PAUSE 200
PORTA=PORTA*2
WEND


iii.
PORTA.0=1
PAUSE 200
PORTA.0=0
PORTA.1=1
PAUSE 200
PORTA.1=0
PORTA.2=1
PAUSE 200
PORTA.2=0
PORTA.3=1
PAUSE 200
PORTA.3=0
PORTA.4=1
PAUSE 200
PORTA.4=0
PORTA.5=1
PAUSE 200
PORTA.5=0
PORTA.6=1
PAUSE 200
PORTA.6=0
PORTA.7=1
PAUSE 200
PORTA.7=0

iv.
PORTA=1
PAUSE 200
PORTA=2
PAUSE 200
PORTA=4
PAUSE 200
PORTA=8
PAUSE 200
PORTA=16
PAUSE 200
PORTA=32
PAUSE 200
PORTA=64
PAUSE 200
PORTA=128
PAUSE 200
PORTA=0

#CONFIG  CONFIG  FOSC=INTIO67, PLLCFG=OFF, PRICLKEN=OFF, FCMEN=OFF, IESO=OFF
  CONFIG  PWRTEN=OFF, BOREN=SBORDIS, BORV=190, WDTEN=ON, WDTPS=32768
  CONFIG  CCP2MX=PORTC1, PBADEN=OFF, CCP3MX=PORTB5, HFOFST=ON, T3CMX=PORTC0
  CONFIG  P2BMX=PORTB5, MCLRE=EXTMCLR, STVREN=ON, LVP=OFF, XINST=OFF, DEBUG=OFF
  CONFIG  CP0=OFF, CP1=OFF, CP2=OFF, CP3=OFF, CPB=OFF, CPD=OFF, WRT0=OFF
  CONFIG  WRT1=OFF, WRT2=OFF, WRT3=OFF, WRTC=OFF, WRTB=OFF, WRTD=OFF, EBTR0=OFF
  CONFIG  EBTR1=OFF, EBTR2=OFF, EBTR3=OFF, EBTRB=OFF
#ENDCONFIG


define  OSC 64 
OSCCON    = $70   ; 64Mhz
OSCTUNE.6 =   1     ; Enable 4x PLL




TRISA  = NOT 17 
ansela = ~ $FF




LOOPY:
    
  ;insert code here


    PAUSE 3000
GOTO LOOPY

[astanapane]

im still in lesson 1.



i need to completely understand it with the use of the port schmeatic.

[richard]

make lesson 1 loop like this and try with and without the nop

loopy:
lata=2
pause 10
porta.1 = 0
;@ nop
porta.0 = 1




pause 1000
 
goto loopy

the secret is that leds when forward biased charge up , when you set them low the charge can hold the pin high long enough
to trigger a rmw event on a fast chip. the nop allows enough time for the charge to dissipate {62 nano seconds}

[astanapane]

one by one,

i'm doing some test. Really i have my own way to catch up and understand things.

first of all for lata we can only write up to 255 as it is 8 bit.

I'm still figuring out step by step the diagram.