nRF51_Vdd.cpp

00001 /*
00002  * mbed library program
00003  *  Read nRF51822 VDD volatage and return 100 to 0% charging level
00004  *      https://www.nordicsemi.com/eng/Products/Bluetooth-Smart-Bluetooth-low-energy/nRF51822
00005  *
00006  * Copyright (c) 2016,'18 Kenji Arai / JH1PJL
00007  *  http://www.page.sannet.ne.jp/kenjia/index.html
00008  *  https://os.mbed.com/users/kenjiArai/
00009  *      Created:    January   23rd, 2016
00010  *      Revised:    April     14th, 2018
00011  *
00012  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
00013  * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
00014  * AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
00015  * DAMAGES OR OTHER  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00016  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00017  */
00018 
00019 #include "nRF51_Vdd.h"
00020 #include "nrf_delay.h"
00021 
00022 nRF51_Vdd::nRF51_Vdd(float vdd100percent, float vddzeropercent, uint8_t adc_use){
00023     v100p = vdd100percent;
00024     v0p = vddzeropercent;
00025     use_adc_for_others = adc_use;
00026 }
00027 
00028 nRF51_Vdd::nRF51_Vdd(float vdd100percent, float vddzeropercent){
00029     v100p = vdd100percent;
00030     v0p = vddzeropercent;
00031     use_adc_for_others = USE_ADC;
00032 }
00033 
00034 nRF51_Vdd::nRF51_Vdd(void){
00035     v100p = 3.3f;
00036     v0p = 1.8f;
00037     use_adc_for_others = USE_ADC;
00038 }
00039 
00040 float nRF51_Vdd::read_real_value(void){
00041     NRF_ADC->POWER       = 1;
00042     nrf_delay_us(5);
00043     NRF_ADC->EVENTS_END  = 0;
00044     NRF_ADC->TASKS_STOP  = 1;
00045     reg0 = NRF_ADC->ENABLE;     // save register value
00046     reg1 = NRF_ADC->CONFIG;     // save register value
00047     reg2 = NRF_ADC->RESULT;     // save register value
00048     NRF_ADC->ENABLE = ADC_ENABLE_ENABLE_Enabled;
00049     NRF_ADC->CONFIG = (ADC_CONFIG_RES_10bit << ADC_CONFIG_RES_Pos) |
00050                       (ADC_CONFIG_INPSEL_SupplyOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) |
00051                       (ADC_CONFIG_REFSEL_VBG << ADC_CONFIG_REFSEL_Pos) |
00052                       (ADC_CONFIG_PSEL_Disabled << ADC_CONFIG_PSEL_Pos) |
00053                       (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);
00054     NRF_ADC->EVENTS_END  = 0;
00055     NRF_ADC->TASKS_START = 1;
00056     while (!NRF_ADC->EVENTS_END) {;}
00057     wrk = NRF_ADC->RESULT;          // 10 bit result
00058     NRF_ADC->EVENTS_END  = 0;
00059     NRF_ADC->TASKS_STOP = 1;
00060     if (use_adc_for_others == USE_ADC){
00061         NRF_ADC->ENABLE = reg0;     // recover register value
00062         NRF_ADC->CONFIG = reg1;     // recover register value
00063         NRF_ADC->RESULT = reg2;     // recover register value
00064         NRF_ADC->EVENTS_END  = 0;
00065     } else {
00066         NRF_ADC->CONFIG      = 0x18;
00067         NRF_ADC->EVENTS_END  = 1;
00068         NRF_ADC->TASKS_STOP  = 1;
00069         NRF_ADC->ENABLE      = 0;
00070         nrf_delay_us(5);
00071         NRF_ADC->POWER       = 0;
00072         nrf_delay_us(5);
00073     }
00074     return ((float)wrk / 1024.0f * 1.2f * 3.0f);            
00075 }
00076 
00077 uint8_t nRF51_Vdd::read(void){
00078     wrk_vdd = read_real_value();
00079     if (wrk_vdd <= v0p){
00080         return 0;
00081     } else if (wrk_vdd >= v100p){
00082         return 100;
00083     }
00084     wrk_vdd = (wrk_vdd - v0p) / (v100p - v0p);
00085     return (uint8_t)(wrk_vdd * 100); 
00086 }