I have problems with TPMC0V in 9S08QG8:

1)If I do the following: 

Hi,

first: when posting code, please translate comment or whatever in english: not all the people here speak spanish.

This: 

TPMC0V & = 0x0000; 

what it should do? It's not better to simply write: TPMC0V = 0; ?

are you sure that this:

0x001C * b_two - 0x5455B

gives you what you really want? 0x5a55B is more than 16bit.

Try to put a variable in the middle:

temp = 0x001C * ....

TPMC0V = temp;

and check with the debugger what is temp.

Btw if you do something like this:

TPMC0V = 0;

TPMC0V = 12;

the compiler will delete the first instruction because is useless.

I'm not sure I've answered your questions because I'm not sure I understood what the questions are. 

Bye Jack 

Jack: 
1) thanks for the utmost account. 
2) the idea is to drive a led by PWM. The datos isgoin a MCU for a program terminal V1.9. It controls the duty cycle byTPMC0V.The problem is when I clear TPMC0V, P.E. TPMC0V=0 orTPMC0V&=0X0000,this register not clear, but if I do the following:

while(TPMC0V!=0)

 {

  TPMC0V=0;

 }

this register clear????

How do I know?

For example: if I write in  thefile MCUinit.c of my program PWM4.mcp:

TPMC0V=0x0000; /**/

TPMC0V=0x001C * b_two - 0x5455B;/*TPMC0V takes values from linearequation

 */

and then write streams in the program terminal V1.9: e1e1e5e5e9e9 (loadbuffer) and then ll followed by "enter" (read buffer and loadedTPMC0V), the LED is turned on in low light, then again ll and "enter"increases the intensity, ll and enter again and the light is at maximumbrightness. In contrast, if charge  9e9e5e5e1e1 and pressed successively ll and"enter", the light intensity does not decrease .

However if write:

while(TPMC0V!=0)

 {

  TPMC0V=0;

 }

TPMC0V=0x001C * b_two - 0x5455B;

Works well

I suspect the problem may be the mechanism of loadcoherentización waiting two byte in a buffer before loading on TPMC0V.

3)I send PWM4.mcp for your scrutinizing.

Any suggestion I well welcome

Thank you

Danielito 

PWM4.zip

First of all what's your compiler version? In IDE Alt+F7 -> Compiler for HC08 -> About

Try disassembling both sequences (one with while() and another with &=0) and maybe post relevant asm lines and compiler options here. In both cases I get the same:

5f       [1]             CLRX  
8c       [1]             CLRH  
3500     [5]             STHX  _TPMC0V

Options : -Cs08 -D__NO_FLOAT__ -Ms -WmsgSd1106

Compiler: Codewarrior IDE versión 5.9.0version 2404 (1993-2007)

Compilerfor HC08:

-Cs08-D__NO_FLOAT__ -Ms

Disasssemble:

withTPMC0V&=0X0000;

00aa5f       [1]             CLRX 

00ab8c       [1]             CLRH 

00ac3500     [5]             STHX  _TPMC0V

With  While()

00ac5f       [1]             CLRX 

00ad8c       [1]             CLRH 

00ae3500     [5]             STHX  _TPMC0V

00b0          LB0:   

00b0 5500     [4]             LDHX  _TPMC0V

See thereply a Jag

Thank you.

I see a line more related to load  TPMC0V, therefore not appear assame way.Morover, in the case of setence While() should be expected to enforcethe condition that TPMC0V to clear before exitin the loop. At least is what Iunderstood by now.

Thank you