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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| 18F26K22 (I2C + PWM) = Conflict |
 Posted: Thu Oct 19, 2017 8:48 am |
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Hello,
I want to use I2C and PWM at same time, but this is not working.
I have two slaves on i2c bus, an lcd driver (brightness is controlled by PWM) and a ds3231 rtc. So, if use only PWM to control brightness it works all fine. If I use only ds3231 it works well. But, if join brightness control (PWM) and rtc code, rtc hangs on " communication_status = ds3231_read_configuration();"
When testing all together, if duty cycle is at 0%, all works. If I set duty cycle to 50%, then rtc hangs on the read configuration.
Someone understands this? I need help... thanks.
I'm using PCH Compiler 5.070
| Code: | #include <18F26K22.h>
#device adc=10
#FUSES INTRC_IO // INTRC_IO Internal RC Osc, no CLKOUT
#FUSES NOFCMEN //Fail-safe clock monitor disabled
#FUSES NOIESO //Internal External Switch Over mode disabled
#FUSES NOPUT //No Power Up Timer
#FUSES NOBROWNOUT //No brownout reset
#FUSES NOWDT //No Watch Dog Timer
#FUSES NOPBADEN //PORTB pins are configured as digital I/O on RESET
#FUSES NOMCLR //Master Clear pin NOT enabled
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOXINST //Extended set extension and Indexed Addressing mode disabled (Legacy mode)
#FUSES NODEBUG //No Debug mode for ICD
#FUSES CCP2C1
#use delay(clock = 16000000)
#use rs232(stream = rede, FORCE_SW, baud = 9600, BITS = 8, PARITY = N, STOP = 1, xmit = PIN_C6, rcv = PIN_C7)
#use TIMER(TIMER=1, TICK=1ms, BITS=16, NOISR)
#use I2C(Master, I2C2, slow) // Its using the second slot of i2c
#include "ds3231_v1.3.c"
// variables
unsigned int32 current_tick;
unsigned int32 previous_tick_button;
unsigned int32 previous_tick_menu_exit;
// functions
unsigned int16 tick_difference(unsigned int16 current, unsigned int16 previous) {
return (current - previous);
}
void main(void) {
int h, min, s, dw, dm, m, y, communication_status;
float temperature;
unsigned int16 pwm_value = 0;
// The PWM as 10bits of resolution when midle number is "255"
setup_timer_2(T2_DIV_BY_4, 255, 1); // 16000000/((255+1)*4*4) = 3906 hz
setup_ccp1(CCP_PWM);
setup_ccp2(CCP_PWM);
//
// Set Brightness - set values from 0 - 1024
// MIN: 1023 - 0%
// MID: 512 - 50%
// MAX: 0 - 100%
// Its Inverted
pwm_value = 1023; // use a variable type long int16, to avoid use constante number like "512L"
set_pwm1_duty(pwm_value); //
pwm_value = 1023;
set_pwm2_duty(pwm_value); //
delay_ms(100);
communication_status = ds3231_read_configuration();
if (communication_status) {
fprintf(rede, "\n\r1 - error when communicate with ds3231.");
// ###################
// send ERROR to display
}
current_tick = previous_tick_menu_exit = get_ticks();
while (1) {
current_tick = get_ticks();
if (tick_difference(current_tick, previous_tick_menu_exit) > 1000) {
previous_tick_menu_exit = current_tick; // reset to interval
// Reading ds3231 temperature
ds3218_read_temperature(temperature);
fprintf(rede, "\n\n\rtempRTC: %.2f", temperature);
// Get time
ds3231_read_time(h, min, s);
fprintf(rede, "\n\r%02u:%02u:%02u", h, min, s);
}
}
} |
| Code: | int ds3231_read_configuration() {
int _status;
delay_us(bus_free_time);
i2c_start();
_status = i2c_write(_ds3231_wadd);
_status |= i2c_write(_ds3231_control_reg);
i2c_start();
_status |= i2c_write(_ds3231_radd);
_ds3231_shadow_ctrlreg = i2c_read(_ack);
_en32khz_shadow = i2c_read(_nack);
i2c_stop();
_en32khz_shadow &= 0x08;
_ds3231_shadow_ctrlreg &= 0xDF; // leave thee CONV bis as zero wich is its normal state
return(_status);
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19540
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| Posted: Thu Oct 19, 2017 9:33 am |
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| CCP1 and CCP2 on this are ECCP's, which means they have pulse steering, so OR in CCP_PULSE_STEERING_A with your PWM setup, which should force the outputs to the PxA pins only. |
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jjacob
Joined: 08 Mar 2008
Posts: 54
Location: PORTUGAL (PORTO)
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| Posted: Thu Oct 19, 2017 9:41 am |
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Dear Ttelmah,
Thanks for your help... It solved my problem. 
| Code: |
// The PWM as 10bits of resolution when midle number is "255"
setup_timer_2(T2_DIV_BY_4, 255, 1); // 16000000/((255+1)*4*4) = 3906 hz
setup_ccp1(CCP_PWM | CCP_PULSE_STEERING_A);
setup_ccp2(CCP_PWM | CCP_PULSE_STEERING_A);
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