PIC Microcontroller 12F675

[nirmala h]

Can anybody explain the configuration bits of a PIC Microcontroller (PIC 12F675)?
Ex: BODEN, WDT, MCLRE etc.. what does it mean & how to set/reset all these ?

 

[g_shyam1682]

Hi friend

For configuration bits of PIC12F675,

Go to Page no.54(Section 9) of PIC12F675 Datasheet.

BODEN: Brown-out Detect Enable bit(4)
1 = BOD enabled
0 = BOD disabled

WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled

MCLRE: GP3/MCLR Pin Function Select bit(5)
1 = GP3/MCLR pin function is MCLR
0 = GP3/MCLR pin function is digital I/O, MCLR internally tied to VDD

Hope this is help you
Shyam

 

[nirmala h]

Hi,

Thank you for the information...

I have read this...

If you could explain what is the significance of each & every bits then it will be very helpful...

 

[PaulHolland]

BODEN: Brown-out Detect Enable bit(4)
1 = BOD enabled
0 = BOD disabled
This Bit is switching on a special circuit that will put your microcontroller PIC12F675 in reset state when the voltage is below a level. This is very usefull for battery power applications !.


WDTE: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled
Watchdog is a circuit that is timing and if you do not reset this timer in software it will reset the PIC. This is usefull for software that can potentially hang in a loop waiting for an event that will never will come.


MCLRE: GP3/MCLR Pin Function Select bit(5)
1 = GP3/MCLR pin function is MCLR
0 = GP3/MCLR pin function is digital I/O, MCLR internally tied to VDD
GP3 pin can be configure as RESET INPUT OR as normal Input only pin. I always use GP3 as input pin since external reset is most of the time not needed.

 

[nirmala h]

Hi PaulHolland,

I would able to set the configuration bits now...

Thank you very much...

 

[don diego]

...
GP3 pin can be configure as RESET INPUT OR as normal Input only pin. I always use GP3 as input pin since external reset is most of the time not needed.

Hi PaulHolland,

Could you please share with your experience about using MCLR as an input pin? I would like to use it in PIC10F222 and I would be thankful for any tips. I'm using ICD2 clone to program and I'm wondering if there could be a problem with programming after external RESET disable. Are you using some delay at the beginning of your programs to allow enter in programming mode?

Thanks in advance,
don diego

 

[cubanflyer]

Hi

You need to look at the configuration word to set this as an input, The datasheet states that this change call only be done during programming, and not when the program is executing.

This is the doc they refer to in the datasheet https://ww1.microchip.com/downloads/en/DeviceDoc/41266C.pdf

 

[g_shyam1682]

Hi Friend

I would like to use it in PIC10F222 and I would be thankful for any tips. I'm using ICD2 clone to program and I'm wondering if there could be a problem with programming after external RESET disable.

if you are use ICD2 Clone for programming purpose,
you can't use GP3/MCLR Pin as input pin.
Because this pin is use as MCLR in ICSP programming.
and after programming done, you can't change function of this pin.

so if you want to use this pin as GP3,
you must used another Programmer like MPLAB PM3 Device Programmer.

Hope this is help you
Shyam

 

[PaulHolland]

Hi PaulHolland,

Could you please share with your experience about using MCLR as an input pin? I would like to use it in PIC10F222 and I would be thankful for any tips. I'm using ICD2 clone to program and I'm wondering if there could be a problem with programming after external RESET disable. Are you using some delay at the beginning of your programs to allow enter in programming mode?

Thanks in advance,
don diego

Hi Don,

You simply set the config word to use GP3 as input pin and on your hardware side you need to put a resistor of 10K -- 33K in between you logic that is driving your GP3 pin. Now you connect th GP3 pin in the normal way to you programmer, ICD2, Clone's or ICD3 / RealICE and you simply program the device. You will get a warning #0033 which you should ignore. I develop this way already for years and in production we do run 50.000 units/year this way.
No matter what others are telling its simply working. The only thing that is not possible is in circuit debugging but if you take the same chip in the microchip line with more pins this is even possible. No software modifications are needed. If your programmer is using the normal high voltage programming mode it works, only programming with low voltage does not work but all icd2 and clone's are using high voltage programming.

regards, PaulHolland

 

[don diego]

Thanks for answer Paul. I have checked reprogramming with different MCLR configuration and there was no problem

 

[PaulHolland]

Keep in mind that GP3 does not have a pull-up resistor inside and no latch-up diode to Vcc so ALWAYS make sure the voltage on this pin is not more than vcc otherwise the pic will go into programming mode

 

[don diego]

Keep in mind that GP3 does not have a pull-up resistor inside and no latch-up diode to Vcc so ALWAYS make sure the voltage on this pin is not more than vcc otherwise the pic will go into programming mode

Good point about this voltage. I didn't know that. I have external pull-up resistor and in my project GP3 is used only to read a state of switch, which is shorting to ground.

 

[Kandeepan]

Hi, Could any one help me to program to flash two LEDs alternatively.I'm using PIC12F675. 90 Flashes per minute. using CCS compiler.Thank you in advance.