HiI'm trying TIM1 as an up-counter, and want to vary the duty cycle on my
custom board where GPIO C7 (TIM1Ch2) - initialized as a push pull o/p, and
connected to an LED to ground - is the pin I have to use for this.
I'm Looking for a good source to understand the set up sequences and values,
since I am going bit banging.
The SPL example does not mention anything about changing the values of the
option bytes, but I see that in my STM8S003F3P6 chip(20 pin tssop) I need to
set the AFR0 bit of OPT2 (as well as NOPT2) to use the TIM1Ch2 alternate
function. My master clock is HSI at 16MHz.
Am I on the right track?
If not, please give some pointers to where I can get the whole info on setting
up TIM1. The O/P remains at 0V, though the code where the duty cycle is
supposed to vary is running, and the duty cycle variable varies. I use an led
blinking at different rates to tell me where the code is running, and an LCD to
display the contents of the variables, since I have not been able to get the
hang of debugging SDCC generated code with ST-Link V2
Your help is appreciated.
I've tried to use the SPL code (the example SPL code) as much as possible,
modified for my card, and since I'm using SDCC, I removed the enums statements,
and instead defined the values wherever needed.
This is the code I use to initialize TIM1:
#define P6_OPT2 0x4803#define P6_NOPT2 0x4804#define P6_AFR0 0x01
period=maxduty;
duty=period/2;
TIM1_DeInit(); TIM1_TimeBaseInit(100, TIM1_COUNTERMODE_UP, period, 0);
TIM1_OC2Init(TIM1_OCMODE_PWM2, TIM1_OUTPUTSTATE_ENABLE,
TIM1_OUTPUTNSTATE_DISABLE, duty, TIM1_OCPOLARITY_HIGH, TIM1_OCNPOLARITY_LOW,
TIM1_OCIDLESTATE_RESET, TIM1_OCNIDLESTATE_SET);
/* TIM1 counter enable */ TIM1_Cmd(ENABLE);
/* TIM1 Main Output Enable */ TIM1_CtrlPWMOutputs(ENABLE); _SFR_(P6_OPT2) |=
P6_AFR0; _SFR_(P6_NOPT2) &= ~P6_AFR0;
if(!runup) { duty+=10; LEDSpeed=3; //blink red LED fast in
interrupt SLCD_Position(1,0); SLCD_PrChar('U'); } else { duty-=10; LEDSpeed=2;
//blink red LED slow in interrupt SLCD_Position(1,0); SLCD_PrChar('D');
} PC_ODR ^= (1 << LO_PIN); //Set LED ON //toggle green LED
if(duty>= period) { duty=period; runup=1; } if(duty<=0) { duty=0; runup=0; }
SLCD_Position(1,8); SLCD_PrHexInt(duty); TIM2_CCR2H = duty >>8; TIM2_CCR2L =
duty;
Thanks and Warm Regards
Shiv
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