added prescaler for 16 bit pwm in LPC1347 target
Fork of mbed-dev by
Diff: targets/hal/TARGET_Maxim/TARGET_MAX32600/pwmout_api.c
- Revision:
- 0:9b334a45a8ff
- Child:
- 144:ef7eb2e8f9f7
diff -r 000000000000 -r 9b334a45a8ff targets/hal/TARGET_Maxim/TARGET_MAX32600/pwmout_api.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/hal/TARGET_Maxim/TARGET_MAX32600/pwmout_api.c Thu Oct 01 15:25:22 2015 +0300 @@ -0,0 +1,213 @@ +/******************************************************************************* + * Copyright (C) 2015 Maxim Integrated Products, Inc., All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL MAXIM INTEGRATED BE LIABLE FOR ANY CLAIM, DAMAGES + * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + * + * Except as contained in this notice, the name of Maxim Integrated + * Products, Inc. shall not be used except as stated in the Maxim Integrated + * Products, Inc. Branding Policy. + * + * The mere transfer of this software does not imply any licenses + * of trade secrets, proprietary technology, copyrights, patents, + * trademarks, maskwork rights, or any other form of intellectual + * property whatsoever. Maxim Integrated Products, Inc. retains all + * ownership rights. + ******************************************************************************* + */ + +#include "mbed_assert.h" +#include "cmsis.h" +#include "pwmout_api.h" +#include "pinmap.h" +#include "ioman_regs.h" +#include "clkman_regs.h" +#include "PeripheralPins.h" + +//****************************************************************************** +void pwmout_init(pwmout_t* obj, PinName pin) +{ + // Make sure the pin is free for GPIO use + unsigned int port = (unsigned int)pin >> PORT_SHIFT; + unsigned int port_pin = (unsigned int)pin & ~(0xFFFFFFFF << PORT_SHIFT); + MBED_ASSERT(MXC_GPIO->free[port] & (0x1 << port_pin)); + + int i = 0; + PinMap pwm = PinMap_PWM[0]; + + // Check if there is a pulse train already active on this port + int pin_func = (MXC_GPIO->func_sel[port] & (0xF << (port_pin*4))) >> (port_pin*4); + MBED_ASSERT((pin_func < 1) || (pin_func > 3)); + + // Search through PinMap_PWM to find the pin + while(pwm.pin != pin) { + pwm = PinMap_PWM[++i]; + } + + // Find a free PT instance on this pin + while(pwm.pin == pin) { + + // Check to see if this PT instance is free + if((((mxc_pt_regs_t*)pwm.peripheral)->rate_length & + MXC_F_PT_RATE_LENGTH_MODE)) { + break; + } + + pwm = PinMap_PWM[++i]; + + // Raise an assertion if we can not allocate another PT instance. + MBED_ASSERT(pwm.pin == pin); + } + + // Enable the clock + MXC_CLKMAN->clk_ctrl_2_pt = MXC_E_CLKMAN_CLK_SCALE_ENABLED; + + // Set the obj pointer to the propper PWM instance + obj->pwm = (mxc_pt_regs_t*)pwm.peripheral; + + // Initialize object period and pulse width + obj->period = -1; + obj->pulse_width = -1; + + // Disable the output + obj->pwm->train = 0x0; + obj->pwm->rate_length = 0x0; + + // Configure the pin + pin_mode(pin, (PinMode)PullNone); + pin_function(pin, pwm.function); + + // default to 20ms: standard for servos, and fine for e.g. brightness control + pwmout_period_us(obj, 20000); + pwmout_write (obj, 0); + + // Set the drive mode to normal + MXC_SET_FIELD(&MXC_GPIO->out_mode[port], (0x7 << (port_pin*4)), (MXC_V_GPIO_OUT_MODE_NORMAL_DRIVE << (port_pin*4))); + + // Enable the global pwm + MXC_PTG->ctrl = MXC_F_PT_CTRL_ENABLE_ALL; +} + +//****************************************************************************** +void pwmout_free(pwmout_t* obj) +{ + // Set the registers to the reset value + obj->pwm->train = 0; + obj->pwm->rate_length = 0x08000000; +} + +//****************************************************************************** +static void pwmout_update(pwmout_t* obj) +{ + // Calculate and set the divider ratio + int div = (obj->period * (SystemCoreClock/1000000))/32; + if (div < 2){ + div = 2; + } + MXC_SET_FIELD(&obj->pwm->rate_length, MXC_F_PT_RATE_LENGTH_RATE_CONTROL, div); + + // Change the duty cycle to adjust the pulse width + obj->pwm->train = (0xFFFFFFFF << (32-((32*obj->pulse_width)/obj->period))); +} + + +//****************************************************************************** +void pwmout_write(pwmout_t* obj, float percent) +{ + // Saturate percent if outside of range + if(percent < 0.0) { + percent = 0.0; + } else if(percent > 1.0) { + percent = 1.0; + } + + // Resize the pulse width to set the duty cycle + pwmout_pulsewidth_us(obj, (int)(percent*obj->period)); +} + +//****************************************************************************** +float pwmout_read(pwmout_t* obj) +{ + // Check for when pulsewidth or period equals 0 + if((obj->pulse_width == 0) || (obj->period == 0)){ + return 0; + } + + // Return the duty cycle + return ((float)obj->pulse_width / (float)obj->period); +} + +//****************************************************************************** +void pwmout_period(pwmout_t* obj, float seconds) +{ + pwmout_period_us(obj, (int)(seconds * 1000000.0)); +} + +//****************************************************************************** +void pwmout_period_ms(pwmout_t* obj, int ms) +{ + pwmout_period_us(obj, ms*1000); +} + +//****************************************************************************** +void pwmout_period_us(pwmout_t* obj, int us) +{ + // Check the range of the period + MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32))); + + // Set pulse width to half the period if uninitialized + if(obj->pulse_width == -1){ + obj->pulse_width = us/2; + } + + // Save the period + obj->period = us; + + // Update the registers + pwmout_update(obj); +} + +//****************************************************************************** +void pwmout_pulsewidth(pwmout_t* obj, float seconds) +{ + pwmout_pulsewidth_us(obj, (int)(seconds * 1000000.0)); +} + +//****************************************************************************** +void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) +{ + pwmout_pulsewidth_us(obj, ms*1000); +} + +//****************************************************************************** +void pwmout_pulsewidth_us(pwmout_t* obj, int us) +{ + // Check the range of the pulsewidth + MBED_ASSERT((us >= 0) && (us <= (int)(SystemCoreClock/32))); + + // Initialize period to double the pulsewidth if uninitialized + if(obj->period == -1){ + obj->period = 2*us; + } + + // Save the pulsewidth + obj->pulse_width = us; + + // Update the register + pwmout_update(obj); +}