/* Copyright (c) 2016 Takafumi Naka. All Rights Reserved.

*

* Licensees are granted free, non-transferable use of the information. NO

* WARRANTY of ANY KIND is provided. This heading must NOT be removed from

* the file.

*

*/

#include "i2s_ws2812b_drive.h"

#include "app_util_platform.h"

#include "nrf_delay.h"

#include "nrf_gpio.h"

volatile uint8_t i2s_ws2812b_drive_flag_buffer_cnt = 0;

static void i2s_ws2812b_drive_handler(uint32_t const * p_data_received,

uint32_t * p_data_to_send,

uint16_t number_of_words)

{

if (p_data_to_send != NULL) {

if (i2s_ws2812b_drive_flag_buffer_cnt == 0) {

// == 0 called before start - do nothing

// == 1 is called just before the second half gets output

} else if (i2s_ws2812b_drive_flag_buffer_cnt == 2) {

// ==3 called before we go back to the beginning.

// Now start setting the next part of the buffer to 0

// to ensure we don't get data repeated

for (int i=0;i<number_of_words;i++)

p_data_to_send[i] = 0;

}

i2s_ws2812b_drive_flag_buffer_cnt++;

}

}

ret_code_t i2s_ws2812b_drive_xfer(rgb_led_t *led_array, uint16_t num_leds, uint8_t drive_pin)

{

#ifdef USE_NEOPIXEL

ret_code_t err_code;

// save pin state before

#ifdef NEOPIXEL_SCK_PIN

uint32_t sckPinNumber = NEOPIXEL_SCK_PIN;

#if NRF_SD_BLE_API_VERSION>5

NRF_GPIO_Type *sckReg = nrf_gpio_pin_port_decode(&sckPinNumber);

#else

NRF_GPIO_Type *sckReg = NRF_GPIO;

#endif

uint32_t sckConf = sckReg->PIN_CNF[sckPinNumber];

#endif

#ifdef NEOPIXEL_LRCK_PIN

uint32_t lrckPinNumber = NEOPIXEL_LRCK_PIN;

#if NRF_SD_BLE_API_VERSION>5

NRF_GPIO_Type *lrckReg = nrf_gpio_pin_port_decode(&lrckPinNumber);

#else

NRF_GPIO_Type *lrckReg = NRF_GPIO;

#endif

uint32_t lrckConf = lrckReg->PIN_CNF[lrckPinNumber];

#endif

// define configs

nrf_drv_i2s_config_t config;

/* The I2S interface refuses to work if SCK isn't defined,

* so we have to define it on a pin where it doesn't matter. */

#ifdef NEOPIXEL_SCK_PIN

config.sck_pin = NEOPIXEL_SCK_PIN;

#else

#error "Must define an SCK pin if using neopixels"

#endif

#ifdef NEOPIXEL_LRCK_PIN

// On nRF52840 lrck needs defining too - http://forum.espruino.com/conversations/354468/

config.lrck_pin = NEOPIXEL_LRCK_PIN;

#else

config.lrck_pin = NRF_DRV_I2S_PIN_NOT_USED;

#endif

config.mck_pin = NRF_DRV_I2S_PIN_NOT_USED;

config.sdout_pin = drive_pin;

config.sdin_pin = NRF_DRV_I2S_PIN_NOT_USED;

config.irq_priority = APP_IRQ_PRIORITY_HIGH;

config.mode = NRF_I2S_MODE_MASTER;

config.format = NRF_I2S_FORMAT_I2S;

config.alignment = NRF_I2S_ALIGN_LEFT;

config.sample_width = NRF_I2S_SWIDTH_16BIT;

config.channels = NRF_I2S_CHANNELS_STEREO;

config.mck_setup = NRF_I2S_MCK_32MDIV10;

config.ratio = NRF_I2S_RATIO_32X;

// initialize i2s

err_code = nrf_drv_i2s_init(&config, i2s_ws2812b_drive_handler);

APP_ERROR_CHECK(err_code);

if ( err_code != NRF_SUCCESS )

{

return err_code;

}

// make buffer

size_t tx_buffer_size = num_leds * (I2S_WS2812B_DRIVE_BUF_SIZE_PER_LED / 4); // size in 32 bit words

tx_buffer_size = (tx_buffer_size+1) & (~1); // round up to ensure it's even (nrf_drv_i2s_start needs this)

uint32_t m_buffer_tx[tx_buffer_size];

i2s_ws2812b_drive_flag_buffer_cnt = 0;

// Set up buffer with all the LED waveform in

uint8_t *p_xfer = (uint8_t *)m_buffer_tx;

uint8_t *p_xfer_end = (uint8_t *)&m_buffer_tx[tx_buffer_size];

rgb_led_t* p_led = led_array;

for(int i_led=0;i_led<num_leds;i_led++) {

uint32_t rgb_data = (p_led->green << 16) | (p_led->red << 8 ) | p_led->blue;

for(uint8_t i_rgb=0;i_rgb<I2S_WS2812B_DRIVE_BUF_SIZE_PER_LED;i_rgb+=2) {

switch(rgb_data & 0x00300000 ) {

case ( 0x00100000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_0 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_1);

break;

case ( 0x00200000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_1 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_0);

break;

case ( 0x00300000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_1 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_1);

break;

default:

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_0 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_0);

}

p_xfer++;

switch(rgb_data & 0x00c00000 ) {

case ( 0x00400000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_0 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_1);

break;

case ( 0x00800000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_1 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_0);

break;

case ( 0x00c00000 ):

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_1 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_1);

break;

default:

*(p_xfer) = (uint8_t)(( I2S_WS2812B_DRIVE_PATTERN_0 << 4 ) | I2S_WS2812B_DRIVE_PATTERN_0);

}

p_xfer++;

rgb_data <<= 4;

}

p_led++;

}

// fill the remainder with 0

while (p_xfer < p_xfer_end)

*(p_xfer++) = 0;

// start transfer

#if NRF_SD_BLE_API_VERSION>5

nrfx_i2s_buffers_t buffers;

buffers.p_rx_buffer = 0;

buffers.p_tx_buffer = m_buffer_tx;

err_code = nrf_drv_i2s_start(&buffers, tx_buffer_size, 0/*flags*/);

#else

err_code = nrf_drv_i2s_start(NULL, m_buffer_tx, tx_buffer_size, 0/*flags*/);

#endif

APP_ERROR_CHECK(err_code);

if ( err_code != NRF_SUCCESS )

{

return err_code;

}

// wait for transmit to finish - for some reason we have to

// wait for the 5th call to i2s_ws2812b_drive_handler.

// Not 100% sure why this is - presumably it's pre-buffering

// as far in advance as it can.

while (i2s_ws2812b_drive_flag_buffer_cnt < 5);

// finally, stop the output

nrf_drv_i2s_stop();

// un-initialize i2s

nrf_drv_i2s_uninit();

// I2S not only uses pins when it's not supposed to, it doesn't

// even de-allocate them after so we must do it manually

// https://github.com/espruino/Espruino/issues/2071

NRF_I2S->PSEL.SCK = NRF_DRV_I2S_PIN_NOT_USED;

NRF_I2S->PSEL.LRCK = NRF_DRV_I2S_PIN_NOT_USED;

#ifdef NEOPIXEL_SCK_PIN

sckReg->PIN_CNF[sckPinNumber] = sckConf;

#endif

#ifdef NEOPIXEL_LRCK_PIN

lrckReg->PIN_CNF[lrckPinNumber] = lrckConf;

#endif

#endif

return NRF_SUCCESS;

}