| /*************************************************************************** |
| * __________ __ ___. |
| * Open \______ \ ____ ____ | | _\_ |__ _______ ___ |
| * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / |
| * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < |
| * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ |
| * \/ \/ \/ \/ \/ |
| * $Id:$ |
| * |
| * Copyright (C) 2010 Marcin Bukat |
| * |
| * This program 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 2 |
| * of the License, or (at your option) any later version. |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| * KIND, either express or implied. |
| * |
| ****************************************************************************/ |
| |
| #include "config.h" |
| #include "cpu.h" |
| #include "system.h" |
| #include "kernel.h" |
| #include "thread.h" |
| #include "adc.h" |
| |
| volatile unsigned short adc_data[NUM_ADC_CHANNELS] IBSS_ATTR; |
| |
| /* Reading takes 4096 adclk ticks |
| * 1) tick task is created that enables ADC interrupt |
| * 2) On interrupt single channel is readed and |
| * ADC is prepared for next channel |
| * 3) When all 4 channels are scanned ADC interrupt is disabled |
| */ |
| |
| void ADC(void) __attribute__ ((interrupt_handler,section(".icode"))); |
| void ADC(void) |
| { |
| static unsigned char channel IBSS_ATTR; |
| /* read current value */ |
| adc_data[(channel&0x03)] = ADVALUE; |
| |
| /* switch channel |
| * |
| * set source remark |
| * ADCONFIG is 16bit wide so we have to shift data by 16bits left |
| * thats why we shift <<24 instead of <<8 |
| */ |
| |
| channel++; |
| |
| and_l(~(0x03<<24),&ADCONFIG); |
| or_l( (((channel&0x03) << 8 )|(1<<7))<<16, &ADCONFIG); |
| |
| if ( (channel & 0x03) == 0 ) |
| /* disable ADC interrupt */ |
| and_l((~(1<<6))<<16,&ADCONFIG); |
| } |
| |
| unsigned short adc_scan(int channel) |
| { |
| /* maybe we can drop &0x03 part */ |
| return adc_data[(channel&0x03)]; |
| } |
| |
| void adc_tick(void) |
| { |
| /* enable ADC interrupt */ |
| or_l( ((1<<6))<<16, &ADCONFIG); |
| } |
| |
| void adc_init(void) |
| { |
| /* GPIO38 GPIO39 */ |
| and_l(~((1<<6)|(1<<7)), &GPIO1_FUNCTION); |
| |
| /* ADOUT_SEL = 01 |
| * SOURCE SELECT = 000 |
| * CLEAR INTERRUPT FLAG |
| * ENABLE INTERRUPT = 0 |
| * ADOUT_DRIVE = 00 |
| * ADCLK_SEL = 011 (busclk/8) |
| */ |
| |
| ADCONFIG = (1<<10)|(1<<8)|(1<<7)|0x03; |
| |
| /* ADC interrupt level 4.0 */ |
| or_l((4<<28), &INTPRI8); |
| |
| /* create tick task which enables ADC interrupt */ |
| tick_add_task(adc_tick); |
| } |