diff options
Diffstat (limited to 'tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c')
| -rw-r--r-- | tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c new file mode 100644 index 0000000000..8a17f4be48 --- /dev/null +++ b/tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/hal/TARGET_NXP/TARGET_LPC15XX/pwmout_api.c @@ -0,0 +1,170 @@ +/* mbed Microcontroller Library + * Copyright (c) 2006-2013 ARM Limited + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +#include "mbed_assert.h" +#include "pwmout_api.h" +#include "cmsis.h" +#include "pinmap.h" +#include "mbed_error.h" + +static LPC_SCT0_Type *SCTs[4] = { + (LPC_SCT0_Type*)LPC_SCT0, + (LPC_SCT0_Type*)LPC_SCT1, + (LPC_SCT0_Type*)LPC_SCT2, + (LPC_SCT0_Type*)LPC_SCT3, +}; + +// bit flags for used SCTs +static unsigned char sct_used = 0; +static int get_available_sct(void) { + int i; + for (i=0; i<4; i++) { + if ((sct_used & (1 << i)) == 0) + return i; + } + return -1; +} + +void pwmout_init(pwmout_t* obj, PinName pin) { + MBED_ASSERT(pin != (uint32_t)NC); + + int sct_n = get_available_sct(); + if (sct_n == -1) { + error("No available SCT"); + } + + sct_used |= (1 << sct_n); + obj->pwm = SCTs[sct_n]; + obj->pwm_ch = sct_n; + + LPC_SCT0_Type* pwm = obj->pwm; + + // Enable the SCT clock + LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << (obj->pwm_ch + 2)); + + // Clear peripheral reset the SCT: + LPC_SYSCON->PRESETCTRL1 |= (1 << (obj->pwm_ch + 2)); + LPC_SYSCON->PRESETCTRL1 &= ~(1 << (obj->pwm_ch + 2)); + + switch(obj->pwm_ch) { + case 0: + // SCT0_OUT0 + LPC_SWM->PINASSIGN[7] &= ~0x0000FF00; + LPC_SWM->PINASSIGN[7] |= (pin << 8); + break; + case 1: + // SCT1_OUT0 + LPC_SWM->PINASSIGN[8] &= ~0x000000FF; + LPC_SWM->PINASSIGN[8] |= (pin); + break; + case 2: + // SCT2_OUT0 + LPC_SWM->PINASSIGN[8] &= ~0xFF000000; + LPC_SWM->PINASSIGN[8] |= (pin << 24); + break; + case 3: + // SCT3_OUT0 + LPC_SWM->PINASSIGN[9] &= ~0x00FF0000; + LPC_SWM->PINASSIGN[9] |= (pin << 16); + break; + default: + break; + } + + // Unified 32-bit counter, autolimit + pwm->CONFIG |= ((0x3 << 17) | 0x01); + + // halt and clear the counter + pwm->CTRL |= (1 << 2) | (1 << 3); + + // System Clock -> us_ticker (1)MHz + pwm->CTRL &= ~(0x7F << 5); + pwm->CTRL |= (((SystemCoreClock/1000000 - 1) & 0x7F) << 5); + + // Match reload register + pwm->MATCHREL0 = 20000; // 20ms + pwm->MATCHREL1 = (pwm->MATCHREL0 / 4); // 50% duty + + pwm->OUT0_SET = (1 << 0); // event 0 + pwm->OUT0_CLR = (1 << 1); // event 1 + + pwm->EV0_CTRL = (1 << 12); + pwm->EV0_STATE = 0xFFFFFFFF; + pwm->EV1_CTRL = (1 << 12) | (1 << 0); + pwm->EV1_STATE = 0xFFFFFFFF; + + // unhalt the counter: + // - clearing bit 2 of the CTRL register + pwm->CTRL &= ~(1 << 2); + + // default to 20ms: standard for servos, and fine for e.g. brightness control + pwmout_period_ms(obj, 20); + pwmout_write (obj, 0); +} + +void pwmout_free(pwmout_t* obj) { + // Disable the SCT clock + LPC_SYSCON->SYSAHBCLKCTRL1 &= ~(1 << (obj->pwm_ch + 2)); + sct_used &= ~(1 << obj->pwm_ch); +} + +void pwmout_write(pwmout_t* obj, float value) { + LPC_SCT0_Type* pwm = obj->pwm; + if (value < 0.0f) { + value = 0.0; + } else if (value > 1.0f) { + value = 1.0; + } + uint32_t t_on = (uint32_t)((float)(pwm->MATCHREL0) * value); + pwm->MATCHREL1 = t_on; +} + +float pwmout_read(pwmout_t* obj) { + uint32_t t_off = obj->pwm->MATCHREL0; + uint32_t t_on = obj->pwm->MATCHREL1; + float v = (float)t_on/(float)t_off; + return (v > 1.0f) ? (1.0f) : (v); +} + +void pwmout_period(pwmout_t* obj, float seconds) { + pwmout_period_us(obj, seconds * 1000000.0f); +} + +void pwmout_period_ms(pwmout_t* obj, int ms) { + pwmout_period_us(obj, ms * 1000); +} + +// Set the PWM period, keeping the duty cycle the same. +void pwmout_period_us(pwmout_t* obj, int us) { + LPC_SCT0_Type* pwm = obj->pwm; + uint32_t t_off = pwm->MATCHREL0; + uint32_t t_on = pwm->MATCHREL1; + float v = (float)t_on/(float)t_off; + pwm->MATCHREL0 = (uint32_t)us; + pwm->MATCHREL1 = (uint32_t)((float)us * (float)v); +} + +void pwmout_pulsewidth(pwmout_t* obj, float seconds) { + pwmout_pulsewidth_us(obj, seconds * 1000000.0f); +} + +void pwmout_pulsewidth_ms(pwmout_t* obj, int ms) { + pwmout_pulsewidth_us(obj, ms * 1000); +} + +void pwmout_pulsewidth_us(pwmout_t* obj, int us) { + obj->pwm->MATCHREL1 = (uint32_t)us; +} + |