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webgiorgio
Joined: 02 Oct 2009
Posts: 123
Location: Denmark
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| PIN_A7 at 5V but reading zero |
 Posted: Sat Jun 10, 2017 1:50 am |
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Saturday morning headaches:
I have 3 pushbuttons connected to A7, A6 and C0 with 10 kohm pull-up resisotrs.
The program should show on the LCD screen which button is pressed.
The problem is that the LCD shows the text "up" also when the button "up" is not pressed.
PIN_A7 (button "up") is at 5V as I measured with a multimeter on the pin, but the uC sees it low. What is wrong in my program?
Compiler: 5.034 PCWH
PIC16F1788 datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/40001675C.pdf
| Code: | #include <16f1788.h>
#fuses NOWDT,NOPROTECT,NOBROWNOUT,NOLVP // configura fuses
//#device ICD = TRUE
#use delay(clock=8M)
#use i2c(Master, sda=PIN_C4, scl=PIN_C3)
#include <i2c_Flex_LCD.h>
void main()
{
setup_oscillator(OSC_8MHZ);
lcd_init();
delay_ms(20);
lcd_clear();
printf(LCD_PUTC,"\1 * test * ");
delay_ms(1000);
while(TRUE)
{
lcd_clear();
delay_ms(20);
if(!input(PIN_A7)) printf(LCD_PUTC,"\1 up"); //<-problem!
if(!input(PIN_A6)) printf(LCD_PUTC,"\2 down");
if(!input(PIN_C0)) printf(LCD_PUTC,"\3 ok");
delay_ms(200);
}
}
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Earlier I was using the internal pull-ups, but the uC was having strange behaviour when I was gettign my fingers close to the uC or close to the pushbuttons and their PCB tracks. Then I installed the 3x10k and solved that.
I am using the internal oscillator. |
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webgiorgio
Joined: 02 Oct 2009
Posts: 123
Location: Denmark
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| Posted: Sat Jun 10, 2017 3:31 am |
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I've found the answer! 
| Quote: | | It makes the crystal oscillator pins into normal i/o pins. This should fix RA6 and RA7. |
From https://ccsinfo.com/forum/viewtopic.php?t=51228&start=0
Well, where can I learn what each fuse exacly does?
| Code: | //////// Fuses: LP,XT,HS,RC,INTRC_IO,ECL,ECM,ECH,NOWDT,WDT_SW,WDT_NOSL,WDT
//////// Fuses: PUT,NOPUT,NOMCLR,MCLR,PROTECT,NOPROTECT,CPD,NOCPD,NOBROWNOUT
//////// Fuses: BROWNOUT_SW,BROWNOUT_NOSL,BROWNOUT,CLKOUT,NOCLKOUT,NOIESO
//////// Fuses: IESO,NOFCMEN,FCMEN,WRT,WRT_1000,WRT_200,NOWRT,VCAP,NOVCAP
//////// Fuses: PLL_SW,PLL,NOSTVREN,STVREN,BORV25,BORV19,LPBOR,NOLPBOR,DEBUG
//////// Fuses: NODEBUG,NOLVP,LVP |
Last edited by webgiorgio on Sat Jun 10, 2017 10:42 am; edited 1 time in total |
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temtronic
Joined: 01 Jul 2010
Posts: 9245
Location: Greensville,Ontario
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| Posted: Sat Jun 10, 2017 4:46 am |
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The best place to read about the fuses is the PIC datasheet.
Yes, I know almost 500 pages of dull, dreary reading BUT reading is knowledge !!
Fuses are 'blown' to setup the basic hardware configuration of the PIC. About a 1/4 of them control the 'clock' of your PIC, so reading the 'clock' chapter is crucial in 'getting it right'. At the end of each chapter, there's a table of PIC registers used and the bits used for that 'peripheral' or section of the PIC.
The other place to look is the CCS compiler's 'device header'. It will list the 'options' available for that PIC.
All PICs 'share' a LOT of common technology, so once you understand one, the rest are easy( well, easier.....) |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19546
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| Posted: Sat Jun 10, 2017 7:12 am |
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Other important place is 'fuses.txt' with the compiler.
This gives the CCS names, and tells you what they actually correspond to. |
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webgiorgio
Joined: 02 Oct 2009
Posts: 123
Location: Denmark
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| Posted: Mon Jun 12, 2017 2:18 am |
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In fact a problem I always have is "translate" what I read in the data-sheet (configuration bits...) into CCS C syntax which I find in the 'device header'. That fuses.txt file helps
Thanks! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19546
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| Posted: Mon Jun 12, 2017 6:25 am |
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Yes. Sometimes it is indispensable for this.  |
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