| 1 | /* |
| 2 | This file is part of Smoothie (http://smoothieware.org/). The motion control part is heavily based on Grbl (https://github.com/simen/grbl). |
| 3 | Smoothie is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. |
| 4 | Smoothie is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. |
| 5 | You should have received a copy of the GNU General Public License along with Smoothie. If not, see <http://www.gnu.org/licenses/>. |
| 6 | */ |
| 7 | |
| 8 | #include "Adc.h" |
| 9 | #include "libs/nuts_bolts.h" |
| 10 | #include "libs/Kernel.h" |
| 11 | #include "libs/Pin.h" |
| 12 | #include "libs/ADC/adc.h" |
| 13 | #include "libs/Pin.h" |
| 14 | #include "libs/Median.h" |
| 15 | |
| 16 | #include <cstring> |
| 17 | #include <algorithm> |
| 18 | |
| 19 | #include "mbed.h" |
| 20 | |
| 21 | // This is an interface to the mbed.org ADC library you can find in libs/ADC/adc.h |
| 22 | // TODO : Having the same name is confusing, should change that |
| 23 | |
| 24 | Adc *Adc::instance; |
| 25 | |
| 26 | static void sample_isr(int chan, uint32_t value) |
| 27 | { |
| 28 | Adc::instance->new_sample(chan, value); |
| 29 | } |
| 30 | |
| 31 | Adc::Adc() |
| 32 | { |
| 33 | instance = this; |
| 34 | // ADC sample rate need to be fast enough to be able to read the enabled channels within the thermistor poll time |
| 35 | // even though ther maybe 32 samples we only need one new one within the polling time |
| 36 | const uint32_t sample_rate= 1000; // 1KHz sample rate |
| 37 | this->adc = new mbed::ADC(sample_rate, 8); |
| 38 | this->adc->append(sample_isr); |
| 39 | } |
| 40 | |
| 41 | /* |
| 42 | LPC176x ADC channels and pins |
| 43 | |
| 44 | Adc Channel Port Pin Pin Functions Associated PINSEL Register |
| 45 | AD0 P0.23 0-GPIO, 1-AD0[0], 2-I2SRX_CLK, 3-CAP3[0] 14,15 bits of PINSEL1 |
| 46 | AD1 P0.24 0-GPIO, 1-AD0[1], 2-I2SRX_WS, 3-CAP3[1] 16,17 bits of PINSEL1 |
| 47 | AD2 P0.25 0-GPIO, 1-AD0[2], 2-I2SRX_SDA, 3-TXD3 18,19 bits of PINSEL1 |
| 48 | AD3 P0.26 0-GPIO, 1-AD0[3], 2-AOUT, 3-RXD3 20,21 bits of PINSEL1 |
| 49 | AD4 P1.30 0-GPIO, 1-VBUS, 2- , 3-AD0[4] 28,29 bits of PINSEL3 |
| 50 | AD5 P1.31 0-GPIO, 1-SCK1, 2- , 3-AD0[5] 30,31 bits of PINSEL3 |
| 51 | AD6 P0.3 0-GPIO, 1-RXD0, 2-AD0[6], 3- 6,7 bits of PINSEL0 |
| 52 | AD7 P0.2 0-GPIO, 1-TXD0, 2-AD0[7], 3- 4,5 bits of PINSEL0 |
| 53 | */ |
| 54 | |
| 55 | // Enables ADC on a given pin |
| 56 | void Adc::enable_pin(Pin *pin) |
| 57 | { |
| 58 | PinName pin_name = this->_pin_to_pinname(pin); |
| 59 | int channel = adc->_pin_to_channel(pin_name); |
| 60 | memset(sample_buffers[channel], 0, sizeof(sample_buffers[0])); |
| 61 | |
| 62 | this->adc->burst(1); |
| 63 | this->adc->setup(pin_name, 1); |
| 64 | this->adc->interrupt_state(pin_name, 1); |
| 65 | } |
| 66 | |
| 67 | // Keeps the last 8 values for each channel |
| 68 | // This is called in an ISR, so sample_buffers needs to be accessed atomically |
| 69 | void Adc::new_sample(int chan, uint32_t value) |
| 70 | { |
| 71 | // Shuffle down and add new value to the end |
| 72 | if(chan < num_channels) { |
| 73 | memmove(&sample_buffers[chan][0], &sample_buffers[chan][1], sizeof(sample_buffers[0]) - sizeof(sample_buffers[0][0])); |
| 74 | sample_buffers[chan][num_samples - 1] = (value >> 4) & 0xFFF; // the 12 bit ADC reading |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | //#define USE_MEDIAN_FILTER |
| 79 | // Read the filtered value ( burst mode ) on a given pin |
| 80 | unsigned int Adc::read(Pin *pin) |
| 81 | { |
| 82 | PinName p = this->_pin_to_pinname(pin); |
| 83 | int channel = adc->_pin_to_channel(p); |
| 84 | |
| 85 | uint16_t median_buffer[num_samples]; |
| 86 | // needs atomic access TODO maybe be able to use std::atomic here or some lockless mutex |
| 87 | __disable_irq(); |
| 88 | memcpy(median_buffer, sample_buffers[channel], sizeof(median_buffer)); |
| 89 | __enable_irq(); |
| 90 | |
| 91 | #ifdef USE_MEDIAN_FILTER |
| 92 | // returns the median value of the last 8 samples |
| 93 | return median_buffer[quick_median(median_buffer, num_samples)]; |
| 94 | |
| 95 | #elif defined(OVERSAMPLE) |
| 96 | // Oversample to get 2 extra bits of resolution |
| 97 | // weed out top and bottom worst values then oversample the rest |
| 98 | // put into a 4 element moving average and return the average of the last 4 oversampled readings |
| 99 | static uint16_t ave_buf[num_channels][4] = { {0} }; |
| 100 | std::sort(median_buffer, median_buffer + num_samples); |
| 101 | uint32_t sum = 0; |
| 102 | for (int i = num_samples / 4; i < (num_samples - (num_samples / 4)); ++i) { |
| 103 | sum += median_buffer[i]; |
| 104 | } |
| 105 | // this slows down the rate of change a little bit |
| 106 | ave_buf[channel][3]= ave_buf[channel][2]; |
| 107 | ave_buf[channel][2]= ave_buf[channel][1]; |
| 108 | ave_buf[channel][1]= ave_buf[channel][0]; |
| 109 | ave_buf[channel][0]= sum >> OVERSAMPLE; |
| 110 | return roundf((ave_buf[channel][0]+ave_buf[channel][1]+ave_buf[channel][2]+ave_buf[channel][3])/4.0F); |
| 111 | |
| 112 | #else |
| 113 | // sort the 8 readings and return the average of the middle 4 |
| 114 | std::sort(median_buffer, median_buffer + num_samples); |
| 115 | int sum = 0; |
| 116 | for (int i = num_samples / 4; i < (num_samples - (num_samples / 4)); ++i) { |
| 117 | sum += median_buffer[i]; |
| 118 | } |
| 119 | return sum / (num_samples / 2); |
| 120 | |
| 121 | #endif |
| 122 | } |
| 123 | |
| 124 | // Convert a smoothie Pin into a mBed Pin |
| 125 | PinName Adc::_pin_to_pinname(Pin *pin) |
| 126 | { |
| 127 | if( pin->port == LPC_GPIO0 && pin->pin == 23 ) { |
| 128 | return p15; |
| 129 | } else if( pin->port == LPC_GPIO0 && pin->pin == 24 ) { |
| 130 | return p16; |
| 131 | } else if( pin->port == LPC_GPIO0 && pin->pin == 25 ) { |
| 132 | return p17; |
| 133 | } else if( pin->port == LPC_GPIO0 && pin->pin == 26 ) { |
| 134 | return p18; |
| 135 | } else if( pin->port == LPC_GPIO1 && pin->pin == 30 ) { |
| 136 | return p19; |
| 137 | } else if( pin->port == LPC_GPIO1 && pin->pin == 31 ) { |
| 138 | return p20; |
| 139 | } else { |
| 140 | //TODO: Error |
| 141 | return NC; |
| 142 | } |
| 143 | } |
| 144 | |