ESP8266 Community Forum

- Wed Jan 06, 2016 7:55 pm #38096 Disassemble phy_adc_read_fast() https://github.com/pvvx/esp8266web/blob ... ead_fast.c

void phy_adc_read_fast(uint16 *adc_addr, uint16 adc_num, uint8 adc_clk_div)
uint16 *adc_addr: ADC sample output address
uint16 adc_num: ADC sample count, range [1, 65535]
uint8 adc_clk_div: ADC sample collection clock range[2, 23]

Example(Continue to collect 100 ADC samples):
uint16 adc_out[100];
phy_adc_read_fast(&adc_out[0], 100, 8);

Code: Select allextern uint8 tout_dis_txpwr_track;
void phy_adc_read_fast(uint16 *adc_addr, uint16 adc_num, uint8 adc_clk_div)
{
   tout_dis_txpwr_track = 1;
   if(adc_clk_div < 2) adc_clk_div = 2;
   uint32 save_20 = SAR_BASE[20];
   uint32 save_21 = SAR_BASE[21];
   uint32 save_22 = SAR_BASE[22];
   SAR_BASE[20] = (SAR_BASE[20] & 0xFFFF00FF) | ((adc_clk_div & 0xFF) << 8);
   SAR_BASE[21] = (SAR_BASE[21] & 0xFF000000) | (adc_clk_div * 5 + ((adc_clk_div - 1) << 16) + ((adc_clk_div - 1) << 8) - 1);
   SAR_BASE[22] = (SAR_BASE[22] & 0xFF000000) | (adc_clk_div * 11 + ((adc_clk_div * 3 - 1) << 8) + ((adc_clk_div * 10 - 1) << 16) - 1);
   SAR_BASE[20] &= 0xFFFFFFE3;
   rom_i2c_writeReg_Mask(108,2,0,5,5,1);
   SAR_BASE[23] |= 1 << 21;
   while((SAR_BASE[20] >> 24) & 0x07);   // while(READ_PERI_REG(0x60000D50)&(0x7<<24)); // wait r_state == 0
   while(adc_num--) {
      SAR_BASE[20] &= 0xFFFFFFE3;
      SAR_BASE[20] |= 1 << 1;
      ets_delay_us(1);
      while((SAR_BASE[20] >> 24) & 0x07);   // while(READ_PERI_REG(0x60000D50)&(0x7<<24)); // wait r_state == 0

      uint32 x = ~(SAR_BASE[32]);
      uint32 z = x & 0x7FF;
      x &= 0xFF;
      z &= 0xF00;
      x -= 21;
      if((signed int) x > 0) {
         x = (x * 279) >> 8;
         if(x > 0xff) x = 0xff;
         z += x;
      }
      z++;
      z >>= 1;
      if(chip6_phy_init_ctrl[108] == 0xff) z = 0xFFFF;
      *adc_addr++ = z;
   }
   rom_i2c_writeReg_Mask(108,2,0,5,5,0);
   SAR_BASE[20] = save_20;
   SAR_BASE[21] = save_21;
   SAR_BASE[22] = save_22;
   while((SAR_BASE[20] >> 24) & 0x07);   // while(READ_PERI_REG(0x60000D50)&(0x7<<24)); // wait r_state == 0
   SAR_BASE[23] &= ~(1 << 21);
   SAR_BASE[24] &= ~1;
   SAR_BASE[24] |= 1;
   tout_dis_txpwr_track = 0;
}

Max sample rate ADC ESP8266 ~ = 3 000 000 / adc_clk_div

- Thu Jan 07, 2016 4:44 pm #38163 @pvvx you are an esp8266 hero. I wish I could read all the Russian comments in your code repos though.