add I2S core

2025-04-19 23:22:16 +03:00 · 2015-06-22 15:47:22 +03:00 · 2015-06-22 15:47:22 +03:00 · 3a525e47cf
commit 3a525e47cf
parent ca8ebdbb97
3 changed files with 534 additions and 3 deletions
--- a/cores/esp8266/core_esp8266_i2s.c
+++ b/cores/esp8266/core_esp8266_i2s.c
@ -0,0 +1,223 @@
+/* 
+  si2c.c - Software I2C library for esp8266
+  
+  Code taken and reworked from espessif's I2S example
+  
+  Copyright (c) 2015 Hristo Gochkov. All rights reserved.
+  This file is part of the esp8266 core for Arduino environment.
+ 
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+#include "Arduino.h"
+#include "osapi.h"
+#include "ets_sys.h"
+
+#include "i2s_reg.h"
+#include "i2s.h"
+
+extern void ets_wdt_enable(void);
+extern void ets_wdt_disable(void);
+
+#define SLC_BUF_CNT (8) //Number of buffers in the I2S circular buffer
+#define SLC_BUF_LEN (64) //Length of one buffer, in 32-bit words.
+
+//We use a queue to keep track of the DMA buffers that are empty. The ISR will push buffers to the back of the queue,
+//the mp3 decode will pull them from the front and fill them. For ease, the queue will contain *pointers* to the DMA
+//buffers, not the data itself. The queue depth is one smaller than the amount of buffers we have, because there's
+//always a buffer that is being used by the DMA subsystem *right now* and we don't want to be able to write to that
+//simultaneously.
+
+struct slc_queue_item {
+  uint32  blocksize:12;
+  uint32  datalen:12;
+  uint32  unused:5;
+  uint32  sub_sof:1;
+  uint32  eof:1;
+  uint32  owner:1;
+  uint32  buf_ptr;
+  uint32  next_link_ptr;
+};
+
+static uint32_t i2s_slc_queue[SLC_BUF_CNT-1];
+static uint8_t i2s_slc_queue_len;
+static uint32_t *i2s_slc_buf_pntr[SLC_BUF_CNT]; //Pointer to the I2S DMA buffer data
+static struct slc_queue_item i2s_slc_items[SLC_BUF_CNT]; //I2S DMA buffer descriptors
+
+uint32_t ICACHE_FLASH_ATTR i2s_slc_queue_next_item(){ //pop the top off the queue
+  uint8_t i;
+  uint32_t item = i2s_slc_queue[0];
+  i2s_slc_queue_len--;
+  for(i=0;i<i2s_slc_queue_len;i++)
+    i2s_slc_queue[i] = i2s_slc_queue[i+1];
+  return item;
+}
+
+//This routine is called as soon as the DMA routine has something to tell us. All we
+//handle here is the RX_EOF_INT status, which indicate the DMA has sent a buffer whose
+//descriptor has the 'EOF' field set to 1.
+void ICACHE_FLASH_ATTR i2s_slc_isr(void) {
+  uint32_t slc_intr_status = SLCIS;
+  SLCIC = 0xFFFFFFFF;
+  if (slc_intr_status & SLCIRXEOF) {
+    ETS_SLC_INTR_DISABLE();
+    struct slc_queue_item *finished_item = (struct slc_queue_item*)SLCRXEDA;
+
+    if (i2s_slc_queue_len >= SLC_BUF_CNT-1) { //All buffers are empty. This means we have an underflow
+      i2s_slc_queue_next_item(); //free space for finished_item
+    }
+    i2s_slc_queue[i2s_slc_queue_len++] = finished_item->buf_ptr;
+    ETS_SLC_INTR_ENABLE();
+  }
+}
+
+void ICACHE_FLASH_ATTR i2s_slc_begin(){
+  i2s_slc_queue_len = 0;
+  int x, y;
+  
+  for (x=0; x<SLC_BUF_CNT; x++) {
+    i2s_slc_buf_pntr[x] = malloc(SLC_BUF_LEN*4);
+    for (y=0; y<SLC_BUF_LEN; y++) i2s_slc_buf_pntr[x][y] = 0;
+
+    i2s_slc_items[x].unused = 0;
+    i2s_slc_items[x].owner = 1;
+    i2s_slc_items[x].eof = 1;
+    i2s_slc_items[x].sub_sof = 0;
+    i2s_slc_items[x].datalen = SLC_BUF_LEN*4;
+    i2s_slc_items[x].blocksize = SLC_BUF_LEN*4;
+    i2s_slc_items[x].buf_ptr = (uint32_t)&i2s_slc_buf_pntr[x][0];
+    i2s_slc_items[x].next_link_ptr = (int)((x<(SLC_BUF_CNT-1))?(&i2s_slc_items[x+1]):(&i2s_slc_items[0]));
+  }
+
+  ETS_SLC_INTR_DISABLE();
+  SLCC0 |= SLCRXLR | SLCTXLR;
+  SLCC0 &= ~(SLCRXLR | SLCTXLR);
+  SLCIC = 0xFFFFFFFF;
+
+  //Configure DMA
+  SLCC0 &= ~(SLCMM << SLCM); //clear DMA MODE
+  SLCC0 |= (1 << SLCM); //set DMA MODE to 1
+  SLCRXDC |= SLCBINR | SLCBTNR; //enable INFOR_NO_REPLACE and TOKEN_NO_REPLACE
+  SLCRXDC &= ~(SLCBRXFE | SLCBRXEM | SLCBRXFM); //disable RX_FILL, RX_EOF_MODE and RX_FILL_MODE
+
+  //Feed DMA the 1st buffer desc addr
+  //To send data to the I2S subsystem, counter-intuitively we use the RXLINK part, not the TXLINK as you might
+  //expect. The TXLINK part still needs a valid DMA descriptor, even if it's unused: the DMA engine will throw
+  //an error at us otherwise. Just feed it any random descriptor.
+  SLCTXL &= ~(SLCTXLAM << SLCTXLA); // clear TX descriptor address
+  SLCTXL |= (uint32)&i2s_slc_items[1] << SLCTXLA; //set TX descriptor address. any random desc is OK, we don't use TX but it needs to be valid
+  SLCRXL &= ~(SLCRXLAM << SLCRXLA); // clear RX descriptor address
+  SLCRXL |= (uint32)&i2s_slc_items[0] << SLCRXLA; //set RX descriptor address
+
+  ETS_SLC_INTR_ATTACH(i2s_slc_isr, NULL);
+  SLCIE = SLCIRXEOF; //Enable only for RX EOF interrupt
+
+  ETS_SLC_INTR_ENABLE();
+
+  //Start transmission
+  SLCTXL |= SLCTXLS;
+  SLCRXL |= SLCRXLS;
+}
+
+void ICACHE_FLASH_ATTR i2s_slc_end(){
+  ETS_SLC_INTR_DISABLE();
+  SLCIC = 0xFFFFFFFF;
+  SLCIE = 0;
+  SLCTXL &= ~(SLCTXLAM << SLCTXLA); // clear TX descriptor address
+  SLCRXL &= ~(SLCRXLAM << SLCRXLA); // clear RX descriptor address
+}
+
+//This routine pushes a single, 32-bit sample to the I2S buffers. Call this at (on average) 
+//at least the current sample rate. You can also call it quicker: it will suspend the calling
+//thread if the buffer is full and resume when there's room again.
+
+static uint32_t *i2s_curr_slc_buf=NULL;
+static int i2s_curr_slc_buf_pos=0;
+bool ICACHE_FLASH_ATTR i2s_write_sample(uint32_t sample) {
+  if (i2s_curr_slc_buf_pos==SLC_BUF_LEN || i2s_curr_slc_buf==NULL) {
+    if(i2s_slc_queue_len == 0){
+      while(1){
+        if(i2s_slc_queue_len > 0){
+          break;
+        } else {
+          ets_wdt_disable();
+          ets_wdt_enable();
+        }
+      }
+    }
+    ETS_SLC_INTR_DISABLE();
+    i2s_curr_slc_buf = (uint32_t *)i2s_slc_queue_next_item();
+    ETS_SLC_INTR_ENABLE();
+    i2s_curr_slc_buf_pos=0;
+  }
+  i2s_curr_slc_buf[i2s_curr_slc_buf_pos++]=sample;
+  return true;
+}
+
+bool ICACHE_FLASH_ATTR i2s_write_lr(int16_t left, int16_t right){
+  int sample = right & 0xFFFF;
+  sample = sample << 16;
+  sample |= left & 0xFFFF;
+  return i2s_write_sample(sample);
+}
+
+//  END DMA
+// =========
+// START I2S
+
+
+static uint32_t _i2s_sample_rate;
+
+void ICACHE_FLASH_ATTR i2s_set_rate(uint32_t rate){ //Rate in HZ
+  if(rate == _i2s_sample_rate) return;
+  _i2s_sample_rate = rate;
+  uint32_t i2s_clock_div = (I2SBASEFREQ/(_i2s_sample_rate*32)) & I2SCDM;
+  uint8_t i2s_bck_div = (I2SBASEFREQ/(_i2s_sample_rate*i2s_clock_div*2)) & I2SBDM;
+  //os_printf("Rate %u Div %u Bck %u Frq %u\n", _i2s_sample_rate, i2s_clock_div, i2s_bck_div, I2SBASEFREQ/(i2s_clock_div*i2s_bck_div*2));
+
+  //!trans master, !bits mod, rece slave mod, rece msb shift, right first, msb right
+  I2SC &= ~(I2STSM | (I2SBMM << I2SBM) | (I2SBDM << I2SBD) | (I2SCDM << I2SCD));
+  I2SC |= I2SRF | I2SMR | I2SRSM | I2SRMS | ((i2s_bck_div-1) << I2SBD) | ((i2s_clock_div-1) << I2SCD);
+}
+
+void ICACHE_FLASH_ATTR i2s_begin(){
+  _i2s_sample_rate = 0;
+  i2s_slc_begin();
+  
+  pinMode(2, FUNCTION_1); //I2SO_WS (LRCK)
+  pinMode(3, FUNCTION_1); //I2SO_DATA (SDIN)
+  pinMode(15, FUNCTION_1); //I2SO_BCK (SCLK)
+  
+  I2S_CLK_ENABLE();
+  I2SIC = 0x3F;
+  I2SIE = 0;
+  
+  //Reset I2S
+  I2SC &= ~(I2SRST);
+  I2SC |= I2SRST;
+  I2SC &= ~(I2SRST);
+  
+  I2SFC &= ~(I2SDE | (I2STXFMM << I2STXFM) | (I2SRXFMM << I2SRXFM)); //Set RX/TX FIFO_MOD=0 and disable DMA (FIFO only)
+  I2SFC |= I2SDE; //Enable DMA
+  I2SCC &= ~((I2STXCMM << I2STXCM) | (I2SRXCMM << I2SRXCM)); //Set RX/TX CHAN_MOD=0
+  i2s_set_rate(44100);
+  I2SC |= I2STXS; //Start transmission
+}
+
+void ICACHE_FLASH_ATTR i2s_end(){
+  i2s_slc_end();
+  pinMode(2, INPUT);
+  pinMode(3, INPUT);
+  pinMode(15, INPUT);
+}
--- a/cores/esp8266/esp8266_peri.h
+++ b/cores/esp8266/esp8266_peri.h
@ -27,6 +27,11 @@
 #define ESP8266_DREG(addr) *((volatile uint32_t *)(0x3FF00000+(addr)))
 #define ESP8266_CLOCK 80000000UL

+#define i2c_readReg_Mask(block, host_id, reg_add, Msb, Lsb)  rom_i2c_readReg_Mask(block, host_id, reg_add, Msb, Lsb)
+#define i2c_readReg_Mask_def(block, reg_add) i2c_readReg_Mask(block, block##_hostid,  reg_add,  reg_add##_msb,  reg_add##_lsb)
+#define i2c_writeReg_Mask(block, host_id, reg_add, Msb, Lsb, indata)  rom_i2c_writeReg_Mask(block, host_id, reg_add, Msb, Lsb, indata)
+#define i2c_writeReg_Mask_def(block, reg_add, indata) i2c_writeReg_Mask(block, block##_hostid,  reg_add,  reg_add##_msb,  reg_add##_lsb,  indata)
+
 //CPU Register
 #define CPU2X     ESP8266_DREG(0x14) //when bit 0 is set, F_CPU = 160MHz

@ -77,9 +82,6 @@
 #define GPCD   2  //DRIVER 0:normal,1:open drain
 #define GPCS   0  //SOURCE 0:GPIO_DATA,1:SigmaDelta

-extern uint8_t esp8266_gpioToFn[16];
-#define GPF(p) ESP8266_REG(0x800 + esp8266_gpioToFn[(p & 0xF)])
-
 #define GPMUX  ESP8266_REG(0x800)
 //GPIO (0-15) PIN Function Registers
 #define GPF0   ESP8266_REG(0x834)
@ -99,6 +101,9 @@ extern uint8_t esp8266_gpioToFn[16];
 #define GPF14  ESP8266_REG(0x80C)
 #define GPF15  ESP8266_REG(0x810)

+extern uint8_t esp8266_gpioToFn[16];
+#define GPF(p) ESP8266_REG(0x800 + esp8266_gpioToFn[(p & 0xF)])
+
 //GPIO (0-15) PIN Function Bits
 #define GPFSOE 0 //Sleep OE
 #define GPFSS  1 //Sleep Sel
@ -579,4 +584,254 @@ extern uint8_t esp8266_gpioToFn[16];
 #define SPIE2IHEN 0x3 //SPI_INT_HOLD_ENA
 #define SPIE2IHEN_S 0 //SPI_INT_HOLD_ENA_S

+
+//SLC (DMA) Registers
+#define SLCC0     ESP8266_REG(0xB00) //SLC_CONF0
+#define SLCIR     ESP8266_REG(0xB04) //SLC_INT_RAW
+#define SLCIS     ESP8266_REG(0xB08) //SLC_INT_STATUS
+#define SLCIE     ESP8266_REG(0xB0C) //SLC_INT_ENA
+#define SLCIC     ESP8266_REG(0xB10) //SLC_INT_CLR
+#define SLCRXS    ESP8266_REG(0xB14) //SLC_RX_STATUS
+#define SLCRXP    ESP8266_REG(0xB18) //SLC_RX_FIFO_PUSH
+#define SLCTXS    ESP8266_REG(0xB1C) //SLC_TX_STATUS
+#define SLCTXP    ESP8266_REG(0xB20) //SLC_TX_FIFO_POP
+#define SLCRXL    ESP8266_REG(0xB24) //SLC_RX_LINK
+#define SLCTXL    ESP8266_REG(0xB28) //SLC_TX_LINK
+#define SLCIVTH   ESP8266_REG(0xB2C) //SLC_INTVEC_TOHOST
+#define SLCT0     ESP8266_REG(0xB30) //SLC_TOKEN0
+#define SLCT1     ESP8266_REG(0xB34) //SLC_TOKEN1
+#define SLCC1     ESP8266_REG(0xB38) //SLC_CONF1
+#define SLCS0     ESP8266_REG(0xB3C) //SLC_STATE0
+#define SLCS1     ESP8266_REG(0xB40) //SLC_STATE1
+#define SLCBC     ESP8266_REG(0xB44) //SLC_BRIDGE_CONF
+#define SLCRXEDA  ESP8266_REG(0xB48) //SLC_RX_EOF_DES_ADDR
+#define SLCTXEDA  ESP8266_REG(0xB4C) //SLC_TX_EOF_DES_ADDR
+#define SLCRXEBDA ESP8266_REG(0xB50) //SLC_RX_EOF_BFR_DES_ADDR
+#define SLCAT     ESP8266_REG(0xB54) //SLC_AHB_TEST
+#define SLCSS     ESP8266_REG(0xB58) //SLC_SDIO_ST
+#define SLCRXDC   ESP8266_REG(0xB5C) //SLC_RX_DSCR_CONF
+#define SLCTXD    ESP8266_REG(0xB60) //SLC_TXLINK_DSCR
+#define SLCTXDB0  ESP8266_REG(0xB64) //SLC_TXLINK_DSCR_BF0
+#define SLCTXDB1  ESP8266_REG(0xB68) //SLC_TXLINK_DSCR_BF1
+#define SLCRXD    ESP8266_REG(0xB6C) //SLC_RXLINK_DSCR
+#define SLCRXDB0  ESP8266_REG(0xB70) //SLC_RXLINK_DSCR_BF0
+#define SLCRXDB1  ESP8266_REG(0xB74) //SLC_RXLINK_DSCR_BF1
+#define SLCDT     ESP8266_REG(0xB78) //SLC_DATE
+#define SLCID     ESP8266_REG(0xB7C) //SLC_ID
+#define SLCHIR    ESP8266_REG(0xB88) //SLC_HOST_INTR_RAW
+#define SLCHC0    ESP8266_REG(0xB94) //SLC_HOST_CONF_W0
+#define SLCHC1    ESP8266_REG(0xB98) //SLC_HOST_CONF_W1
+#define SLCHIS    ESP8266_REG(0xB9C) //SLC_HOST_INTR_ST
+#define SLCHC2    ESP8266_REG(0xBA0) //SLC_HOST_CONF_W2
+#define SLCHC3    ESP8266_REG(0xBA4) //SLC_HOST_CONF_W3
+#define SLCHC4    ESP8266_REG(0xBA8) //SLC_HOST_CONF_W4
+#define SLCHIC    ESP8266_REG(0xBB0) //SLC_HOST_INTR_CLR
+#define SLCHIE    ESP8266_REG(0xBB4) //SLC_HOST_INTR_ENA
+#define SLCHC5    ESP8266_REG(0xBBC) //SLC_HOST_CONF_W5
+
+//SLC (DMA) CONF0
+#define SLCMM     (0x3) //SLC_MODE
+#define SLCM      (12) //SLC_MODE_S
+#define SLCDTBE   (1 << 9) //SLC_DATA_BURST_EN
+#define SLCDBE    (1 << 8) //SLC_DSCR_BURST_EN
+#define SLCRXNRC  (1 << 7) //SLC_RX_NO_RESTART_CLR
+#define SLCRXAW   (1 << 6) //SLC_RX_AUTO_WRBACK
+#define SLCRXLT   (1 << 5) //SLC_RX_LOOP_TEST
+#define SLCTXLT   (1 << 4) //SLC_TX_LOOP_TEST
+#define SLCAR     (1 << 3) //SLC_AHBM_RST
+#define SLCAFR    (1 << 2) //SLC_AHBM_FIFO_RST
+#define SLCRXLR   (1 << 1) //SLC_RXLINK_RST
+#define SLCTXLR   (1 << 0) //SLC_TXLINK_RST
+
+//SLC (DMA) INT
+#define SLCITXDE  (1 << 21) //SLC_TX_DSCR_EMPTY_INT
+#define SLCIRXDER (1 << 20) //SLC_RX_DSCR_ERR_INT
+#define SLCITXDER (1 << 19) //SLC_TX_DSCR_ERR_INT
+#define SLCITH    (1 << 18) //SLC_TOHOST_INT
+#define SLCIRXEOF (1 << 17) //SLC_RX_EOF_INT
+#define SLCIRXD   (1 << 16) //SLC_RX_DONE_INT
+#define SLCITXEOF (1 << 15) //SLC_TX_EOF_INT
+#define SLCITXD   (1 << 14) //SLC_TX_DONE_INT
+#define SLCIT0    (1 << 13) //SLC_TOKEN1_1TO0_INT
+#define SLCIT1    (1 << 12) //SLC_TOKEN0_1TO0_INT
+#define SLCITXO   (1 << 11) //SLC_TX_OVF_INT
+#define SLCIRXU   (1 << 10) //SLC_RX_UDF_INT
+#define SLCITXS   (1 << 9) //SLC_TX_START_INT
+#define SLCIRXS   (1 << 8) //SLC_RX_START_INT
+#define SLCIFH7   (1 << 7) //SLC_FRHOST_BIT7_INT
+#define SLCIFH6   (1 << 6) //SLC_FRHOST_BIT6_INT
+#define SLCIFH5   (1 << 5) //SLC_FRHOST_BIT5_INT
+#define SLCIFH4   (1 << 4) //SLC_FRHOST_BIT4_INT
+#define SLCIFH3   (1 << 3) //SLC_FRHOST_BIT3_INT
+#define SLCIFH2   (1 << 2) //SLC_FRHOST_BIT2_INT
+#define SLCIFH1   (1 << 1) //SLC_FRHOST_BIT1_INT
+#define SLCIFH0   (1 << 0) //SLC_FRHOST_BIT0_INT
+
+//SLC (DMA) RX_STATUS
+#define SLCRXE    (1 << 1) //SLC_RX_EMPTY
+#define SLCRXF    (1 << 0) //SLC_RX_FULL
+
+//SLC (DMA) TX_STATUS
+#define SLCTXE    (1 << 1) //SLC_TX_EMPTY
+#define SLCTXF    (1 << 0) //SLC_TX_FULL
+
+//SLC (DMA) RX_FIFO_PUSH
+#define SLCRXFP   (1 << 16) //SLC_RXFIFO_PUSH
+#define SLCRXWDM  (0x1FF)   //SLC_RXFIFO_WDATA
+#define SLCRXWD   (0)       //SLC_RXFIFO_WDATA_S
+
+//SLC (DMA) TX_FIFO_POP
+#define SLCTXFP   (1 << 16) //SLC_TXFIFO_POP
+#define SLCTXRDM  (0x7FF)   //SLC_TXFIFO_RDATA
+#define SLCTXRD   (0)       //SLC_TXFIFO_RDATA_S
+
+//SLC (DMA) RX_LINK
+#define SLCRXLP   (1 << 31) //SLC_RXLINK_PARK
+#define SLCRXLRS  (1 << 30) //SLC_RXLINK_RESTART
+#define SLCRXLS   (1 << 29) //SLC_RXLINK_START
+#define SLCRXLE   (1 << 28) //SLC_RXLINK_STOP
+#define SLCRXLAM  (0xFFFF)  //SLC_RXLINK_DESCADDR_MASK
+#define SLCRXLA   (0)       //SLC_RXLINK_ADDR_S
+
+//SLC (DMA) TX_LINK
+#define SLCTXLP   (1 << 31) //SLC_TXLINK_PARK
+#define SLCTXLRS  (1 << 30) //SLC_TXLINK_RESTART
+#define SLCTXLS   (1 << 29) //SLC_TXLINK_START
+#define SLCTXLE   (1 << 28) //SLC_TXLINK_STOP
+#define SLCTXLAM  (0xFFFF)  //SLC_TXLINK_DESCADDR_MASK
+#define SLCTXLA   (0)       //SLC_TXLINK_ADDR_S
+
+//SLC (DMA) TOKENx
+#define SLCTM  (0xFFF)   //SLC_TOKENx_MASK
+#define SLCTT  (16)      //SLC_TOKENx_S
+#define SLCTIM (1 << 14) //SLC_TOKENx_LOCAL_INC_MORE
+#define SLCTI  (1 << 13) //SLC_TOKENx_LOCAL_INC
+#define SLCTW  (1 << 12) //SLC_TOKENx_LOCAL_WR
+#define SLCTDM (0xFFF)   //SLC_TOKENx_LOCAL_WDATA
+#define SLCTD  (0)       //SLC_TOKENx_LOCAL_WDATA_S
+
+//SLC (DMA) BRIDGE_CONF
+#define SLCBFMEM  (0xF)   //SLC_FIFO_MAP_ENA
+#define SLCBFME   (8)     //SLC_FIFO_MAP_ENA_S
+#define SLCBTEEM  (0x3F)  //SLC_TXEOF_ENA
+#define SLCBTEE   (0)     //SLC_TXEOF_ENA_S
+
+//SLC (DMA) AHB_TEST
+#define SLCATAM  (0x3)  //SLC_AHB_TESTADDR
+#define SLCATA   (4)    //SLC_AHB_TESTADDR_S
+#define SLCATMM  (0x7)  //SLC_AHB_TESTMODE
+#define SLCATM   (0)    //SLC_AHB_TESTMODE_S
+
+//SLC (DMA) SDIO_ST
+#define SLCSBM  (0x7)     //SLC_BUS_ST
+#define SLCSB   (12)      //SLC_BUS_ST_S
+#define SLCSW   (1 << 8)  //SLC_SDIO_WAKEUP
+#define SLCSFM  (0xF)     //SLC_FUNC_ST
+#define SLCSF   (4)       //SLC_FUNC_ST_S
+#define SLCSCM  (0x7)     //SLC_CMD_ST
+#define SLCSC   (0)       //SLC_CMD_ST_S
+
+//SLC (DMA) RX_DSCR_CONF
+#define SLCBRXFE  (1 << 20) //SLC_RX_FILL_EN
+#define SLCBRXEM  (1 << 19) //SLC_RX_EOF_MODE
+#define SLCBRXFM  (1 << 18) //SLC_RX_FILL_MODE
+#define SLCBINR   (1 << 17) //SLC_INFOR_NO_REPLACE
+#define SLCBTNR   (1 << 16) //SLC_TOKEN_NO_REPLACE
+#define SLCBPICM  (0xFFFF)  //SLC_POP_IDLE_CNT
+#define SLCBPIC   (0)       //SLC_POP_IDLE_CNT_S
+
+
+// I2S Registers
+#define i2c_bbpll                         0x67
+#define i2c_bbpll_hostid                  4
+#define i2c_bbpll_en_audio_clock_out      4
+#define i2c_bbpll_en_audio_clock_out_msb  7
+#define i2c_bbpll_en_audio_clock_out_lsb  7
+#define I2S_CLK_ENABLE()                  i2c_writeReg_Mask_def(i2c_bbpll, i2c_bbpll_en_audio_clock_out, 1)
+#define I2SBASEFREQ                       (12000000L)
+
+#define I2STXF  ESP8266_REG(0xe00) //I2STXFIFO (32bit)
+#define I2SRXF  ESP8266_REG(0xe04) //I2SRXFIFO (32bit)
+#define I2SC    ESP8266_REG(0xe08) //I2SCONF
+#define I2SIR   ESP8266_REG(0xe0C) //I2SINT_RAW
+#define I2SIS   ESP8266_REG(0xe10) //I2SINT_ST
+#define I2SIE   ESP8266_REG(0xe14) //I2SINT_ENA
+#define I2SIC   ESP8266_REG(0xe18) //I2SINT_CLR
+#define I2ST    ESP8266_REG(0xe1C) //I2STIMING
+#define I2SFC   ESP8266_REG(0xe20) //I2S_FIFO_CONF
+#define I2SRXEN ESP8266_REG(0xe24) //I2SRXEOF_NUM (32bit)
+#define I2SCSD  ESP8266_REG(0xe28) //I2SCONF_SIGLE_DATA (32bit)
+#define I2SCC   ESP8266_REG(0xe2C) //I2SCONF_CHAN
+
+// I2S CONF
+#define I2SBDM  (0x3F)    //I2S_BCK_DIV_NUM
+#define I2SBD   (22)      //I2S_BCK_DIV_NUM_S
+#define I2SCDM  (0x3F)    //I2S_CLKM_DIV_NUM
+#define I2SCD   (16)      //I2S_CLKM_DIV_NUM_S
+#define I2SBMM  (0xF)     //I2S_BITS_MOD
+#define I2SBM   (12)      //I2S_BITS_MOD_S
+#define I2SRMS  (1 << 11) //I2S_RECE_MSB_SHIFT
+#define I2STMS  (1 << 10) //I2S_TRANS_MSB_SHIFT
+#define I2SRXS  (1 << 9)  //I2S_I2S_RX_START
+#define I2STXS  (1 << 8)  //I2S_I2S_TX_START
+#define I2SMR   (1 << 7)  //I2S_MSB_RIGHT
+#define I2SRF   (1 << 6)  //I2S_RIGHT_FIRST
+#define I2SRSM  (1 << 5)  //I2S_RECE_SLAVE_MOD
+#define I2STSM  (1 << 4)  //I2S_TRANS_SLAVE_MOD
+#define I2SRXFR (1 << 3)  //I2S_I2S_RX_FIFO_RESET
+#define I2STXFR (1 << 2)  //I2S_I2S_TX_FIFO_RESET
+#define I2SRXR  (1 << 1)  //I2S_I2S_RX_RESET
+#define I2STXR  (1 << 0)  //I2S_I2S_TX_RESET
+#define I2SRST  (0xF)     //I2S_I2S_RESET_MASK
+
+//I2S INT
+#define I2SITXRE  (1 << 5) //I2S_I2S_TX_REMPTY_INT
+#define I2SITXWF  (1 << 4) //I2S_I2S_TX_WFULL_INT
+#define I2SIRXRE  (1 << 3) //I2S_I2S_RX_REMPTY_INT
+#define I2SIRXWF  (1 << 2) //I2S_I2S_RX_WFULL_INT
+#define I2SITXPD  (1 << 1) //I2S_I2S_TX_PUT_DATA_INT
+#define I2SIRXTD  (1 << 0) //I2S_I2S_RX_TAKE_DATA_INT
+
+//I2S TIMING
+#define I2STBII  (1 << 22)  //I2S_TRANS_BCK_IN_INV
+#define I2SRDS   (1 << 21)  //I2S_RECE_DSYNC_SW
+#define I2STDS   (1 << 20)  //I2S_TRANS_DSYNC_SW
+#define I2SRBODM (0x3)      //I2S_RECE_BCK_OUT_DELAY
+#define I2SRBOD  (18)       //I2S_RECE_BCK_OUT_DELAY_S
+#define I2SRWODM (0x3)      //I2S_RECE_WS_OUT_DELAY
+#define I2SRWOD  (16)       //I2S_RECE_WS_OUT_DELAY_S
+#define I2STSODM (0x3)      //I2S_TRANS_SD_OUT_DELAY
+#define I2STSOD  (14)       //I2S_TRANS_SD_OUT_DELAY_S
+#define I2STWODM (0x3)      //I2S_TRANS_WS_OUT_DELAY
+#define I2STWOD  (12)       //I2S_TRANS_WS_OUT_DELAY_S
+#define I2STBODM (0x3)      //I2S_TRANS_BCK_OUT_DELAY
+#define I2STBOD  (10)       //I2S_TRANS_BCK_OUT_DELAY_S
+#define I2SRSIDM (0x3)      //I2S_RECE_SD_IN_DELAY
+#define I2SRSID  (8)        //I2S_RECE_SD_IN_DELAY_S
+#define I2SRWIDM (0x3)      //I2S_RECE_WS_IN_DELAY
+#define I2SRWID  (6)        //I2S_RECE_WS_IN_DELAY_S
+#define I2SRBIDM (0x3)      //I2S_RECE_BCK_IN_DELAY
+#define I2SRBID  (4)        //I2S_RECE_BCK_IN_DELAY_S
+#define I2STWIDM (0x3)      //I2S_TRANS_WS_IN_DELAY
+#define I2STWID  (2)        //I2S_TRANS_WS_IN_DELAY_S
+#define I2STBIDM (0x3)      //I2S_TRANS_BCK_IN_DELAY
+#define I2STBID  (0)        //I2S_TRANS_BCK_IN_DELAY_S
+
+//I2S FIFO CONF
+#define I2SRXFMM (0x7)      //I2S_I2S_RX_FIFO_MOD
+#define I2SRXFM  (16)       //I2S_I2S_RX_FIFO_MOD_S
+#define I2STXFMM (0x7)      //I2S_I2S_TX_FIFO_MOD
+#define I2STXFM  (13)       //I2S_I2S_TX_FIFO_MOD_S
+#define I2SDE    (1 << 12)  //I2S_I2S_DSCR_EN
+#define I2STXDNM (0x3F)     //I2S_I2S_TX_DATA_NUM
+#define I2STXDN  (6)        //I2S_I2S_TX_DATA_NUM_S
+#define I2SRXDNM (0x3F)     //I2S_I2S_RX_DATA_NUM
+#define I2SRXDN  (0)        //I2S_I2S_RX_DATA_NUM_S
+
+//I2S CONF CHAN
+#define I2SRXCMM (0x3)      //I2S_RX_CHAN_MOD
+#define I2SRXCM  (3)        //I2S_RX_CHAN_MOD_S
+#define I2STXCMM (0x7)      //I2S_TX_CHAN_MOD
+#define I2STXCM  (0)        //I2S_TX_CHAN_MOD_S
+
 #endif
--- a/cores/esp8266/i2s.h
+++ b/cores/esp8266/i2s.h
@ -0,0 +1,53 @@
+/* 
+  i2s.h - Software I2C library for esp8266
+
+  Copyright (c) 2015 Hristo Gochkov. All rights reserved.
+  This file is part of the esp8266 core for Arduino environment.
+ 
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library 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
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+#ifndef I2S_h
+#define I2S_h
+
+/*
+How does this work? Basically, to get sound, you need to:
+- Connect an I2S codec to the I2S pins on the ESP.
+- Start up a thread that's going to do the sound output
+- Call i2s_begin()
+- Call i2s_set_rate() with the sample rate you want.
+- Generate sound and call i2s_write_sample() with 32-bit samples.
+The 32bit samples basically are 2 16-bit signed values (the analog values for
+the left and right channel) concatenated as (Rout<<16)+Lout
+
+i2s_write_sample will block when you're sending data too quickly, so you can just
+generate and push data as fast as you can and I2sPushSample will regulate the
+speed.
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void i2s_begin();
+void i2s_end();
+void i2s_set_rate(uint32_t rate);
+bool i2s_write_sample(uint32_t sample);
+bool i2s_write_lr(int16_t left, int16_t right);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif