3 * @author Austin Glaser <austin.glaser@gmail.com>, Joerg Wangemann <joerg.wangemann@gmail.com>
4 * @brief WS2812 LED driver
6 * Copyright (C) 2016 Austin Glaser, 2017 Joerg Wangemann
8 * This software may be modified and distributed under the terms
9 * of the MIT license. See the LICENSE file for details.
11 * @todo Put in names and descriptions of variables which need to be defined to use this file
17 /* --- PRIVATE DEPENDENCIES ------------------------------------------------- */
20 #include "ws2812_f4.h"
33 // TODO: Add these #define's to the headers of your project.
34 // Pin, timer and dma are all connected, check them all if you change one.
35 // Tested with STM32F4, working at 144 or 168 MHz.
36 //#define WS2812_LED_N 2 // Number of LEDs
37 //#define PORT_WS2812 GPIOB
38 //#define PIN_WS2812 9
39 //#define WS2812_TIM_N 4 // timer, 1-11
40 //#define WS2812_TIM_CH 3 // timer channel, 0-3
41 //#define WS2812_DMA_STREAM STM32_DMA1_STREAM2 // DMA stream for TIMx_UP (look up in reference manual under DMA Channel selection)
42 //#define WS2812_DMA_CHANNEL 6 // DMA channel for TIMx_UP
43 // The WS2812 expects 5V signal level (or at least 0.7 * VDD). Sometimes it works
44 // with a 3V signal level, otherwise the easiest way to get the signal level to 5V
45 // is to add an external pullup resistor from the DI pin to 5V (10k will do) and
46 // configure the pin as open drain.
47 // (An SMD resistor is easily solders on the connections of a light strip)
48 // Uncomment the next line if an external pullup resistor is used.
49 //#define WS2812_EXTERNAL_PULLUP
51 /* --- CONFIGURATION CHECK -------------------------------------------------- */
53 #if !defined(WS2812_LED_N)
54 #error WS2812 LED chain length not specified
55 #elif WS2812_LED_N <= 0
56 #error WS2812 LED chain length set to invalid value
59 #if !defined(WS2812_TIM_N)
60 #error WS2812 timer not specified
62 #if defined(STM32F2XX) || defined(STM32F4XX) || defined(STM32F7XX)
65 #elif WS2812_TIM_N <= 5
67 #elif WS2812_TIM_N <= 11
70 #elif !defined(WS2812_AF)
71 #error WS2812_AF timer alternate function not specified
74 #if !defined(WS2812_TIM_CH)
75 #error WS2812 timer channel not specified
76 #elif WS2812_TIM_CH >= 4
77 #error WS2812 timer channel set to invalid value
80 /* --- PRIVATE CONSTANTS ---------------------------------------------------- */
82 #define WS2812_PWM_FREQUENCY (STM32_SYSCLK/2) /**< Clock frequency of PWM, must be valid with respect to system clock! */
83 #define WS2812_PWM_PERIOD (WS2812_PWM_FREQUENCY/800000) /**< Clock period in ticks. 1 / 800kHz = 1.25 uS (as per datasheet) */
86 * @brief Number of bit-periods to hold the data line low at the end of a frame
88 * The reset period for each frame must be at least 50 uS; so we add in 50 bit-times
89 * of zeroes at the end. (50 bits)*(1.25 uS/bit) = 62.5 uS, which gives us some
90 * slack in the timing requirements
92 #define WS2812_RESET_BIT_N (50)
93 #define WS2812_COLOR_BIT_N (WS2812_LED_N*24) /**< Number of data bits */
94 #define WS2812_BIT_N (WS2812_COLOR_BIT_N + WS2812_RESET_BIT_N) /**< Total number of bits in a frame */
97 * @brief High period for a zero, in ticks
101 * - T0H: 200 nS to 500 nS, inclusive
102 * - T0L: 650 nS to 950 nS, inclusive
104 * - T0H: 200 nS to 500 nS, inclusive
105 * - T0L: 750 nS to 1050 nS, inclusive
107 * The duty cycle is calculated for a high period of 350 nS.
109 #define WS2812_DUTYCYCLE_0 (WS2812_PWM_FREQUENCY/(1000000000/450))
112 * @brief High period for a one, in ticks
116 * - T1H: 550 nS to 850 nS, inclusive
117 * - T1L: 450 nS to 750 nS, inclusive
119 * - T1H: 750 nS to 1050 nS, inclusive
120 * - T1L: 200 nS to 500 nS, inclusive
122 * The duty cycle is calculated for a high period of 800 nS.
123 * This is in the middle of the specifications of the WS2812 and WS2812B.
125 #define WS2812_DUTYCYCLE_1 (WS2812_PWM_FREQUENCY/(1000000000/900))
127 /* --- PRIVATE MACROS ------------------------------------------------------- */
130 * @brief Generates a reference to a numbered PWM driver
132 * @param[in] n: The driver (timer) number
134 * @return A reference to the driver
136 #define PWMD(n) CONCAT_EXPANDED_SYMBOLS(PWMD, n)
138 #define WS2812_PWMD PWMD(WS2812_TIM_N) /**< The PWM driver to use for the LED chain */
141 * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given bit
143 * @param[in] led: The led index [0, @ref WS2812_LED_N)
144 * @param[in] byte: The byte number [0, 2]
145 * @param[in] bit: The bit number [0, 7]
147 * @return The bit index
149 #define WS2812_BIT(led, byte, bit) (24*(led) + 8*(byte) + (7 - (bit)))
152 * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given red bit
154 * @note The red byte is the middle byte in the color packet
156 * @param[in] led: The led index [0, @ref WS2812_LED_N)
157 * @param[in] bit: The bit number [0, 7]
159 * @return The bit index
161 #define WS2812_RED_BIT(led, bit) WS2812_BIT((led), 1, (bit))
164 * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given green bit
166 * @note The green byte is the first byte in the color packet
168 * @param[in] led: The led index [0, @ref WS2812_LED_N)
169 * @param[in] bit: The bit number [0, 7]
171 * @return The bit index
173 #define WS2812_GREEN_BIT(led, bit) WS2812_BIT((led), 0, (bit))
176 * @brief Determine the index in @ref ws2812_frame_buffer "the frame buffer" of a given blue bit
178 * @note The blue byte is the last byte in the color packet
180 * @param[in] led: The led index [0, @ref WS2812_LED_N)
181 * @param[in] bit: The bit index [0, 7]
183 * @return The bit index
185 #define WS2812_BLUE_BIT(led, bit) WS2812_BIT((led), 2, (bit))
187 /* --- PRIVATE VARIABLES ---------------------------------------------------- */
189 static uint32_t ws2812_frame_buffer
[WS2812_BIT_N
+ 1]; /**< Buffer for a frame */
191 /* --- PUBLIC FUNCTIONS ----------------------------------------------------- */
193 * Gedanke: Double-buffer type transactions: double buffer transfers using two memory pointers for
194 the memory (while the DMA is reading/writing from/to a buffer, the application can
195 write/read to/from the other buffer).
198 void ws2812_init(void)
200 // Initialize led frame buffer
202 for (i
= 0; i
< WS2812_COLOR_BIT_N
; i
++) ws2812_frame_buffer
[i
] = WS2812_DUTYCYCLE_0
; // All color bits are zero duty cycle
203 for (i
= 0; i
< WS2812_RESET_BIT_N
; i
++) ws2812_frame_buffer
[i
+ WS2812_COLOR_BIT_N
] = 0; // All reset bits are zero
204 // Configure pin as AF output. If there's an external pull up resistor the signal level is brought to 5V using open drain mode.
205 #ifdef WS2812_EXTERNAL_PULLUP
206 palSetPadMode(PORT_WS2812
, PIN_WS2812
, PAL_MODE_ALTERNATE(WS2812_AF
) | PAL_STM32_OTYPE_OPENDRAIN
);
208 palSetPadMode(PORT_WS2812
, PIN_WS2812
, PAL_MODE_ALTERNATE(WS2812_AF
) | PAL_STM32_OTYPE_PUSHPULL
); //PAL_MODE_STM32_ALTERNATE_PUSHPULL);
210 //palClearPad(PORT_WS2812, PIN_WS2812);
213 #pragma GCC diagnostic ignored "-Woverride-init" // Turn off override-init warning for this struct. We use the overriding ability to set a "default" channel config
214 static const PWMConfig ws2812_pwm_config
= {
215 .frequency
= WS2812_PWM_FREQUENCY
,
216 .period
= WS2812_PWM_PERIOD
, //Mit dieser Periode wird UDE-Event erzeugt und ein neuer Wert (Länge WS2812_BIT_N) vom DMA ins CCR geschrieben
219 [0 ... 3] = {.mode
= PWM_OUTPUT_DISABLED
, .callback
= NULL
}, // Channels default to disabled
220 [WS2812_TIM_CH
] = {.mode
= PWM_OUTPUT_ACTIVE_HIGH
, .callback
= NULL
}, // Turn on the channel we care about
223 .dier
= TIM_DIER_UDE
, // DMA on update event for next period
225 #pragma GCC diagnostic pop // Restore command-line warning options
228 //dmaInit(); // Joe added this
229 dmaStreamAllocate(WS2812_DMA_STREAM
, 10, NULL
, NULL
);
230 dmaStreamSetPeripheral(WS2812_DMA_STREAM
, &(WS2812_PWMD
.tim
->CCR
[WS2812_TIM_CH
])); // Ziel ist der An-Zeit im Cap-Comp-Register
231 dmaStreamSetMemory0(WS2812_DMA_STREAM
, ws2812_frame_buffer
);
232 dmaStreamSetTransactionSize(WS2812_DMA_STREAM
, WS2812_BIT_N
);
233 dmaStreamSetMode(WS2812_DMA_STREAM
,
234 STM32_DMA_CR_CHSEL(WS2812_DMA_CHANNEL
) | STM32_DMA_CR_DIR_M2P
| STM32_DMA_CR_PSIZE_WORD
| STM32_DMA_CR_MSIZE_WORD
|
235 STM32_DMA_CR_MINC
| STM32_DMA_CR_CIRC
| STM32_DMA_CR_PL(3));
236 // M2P: Memory 2 Periph; PL: Priority Level
239 dmaStreamEnable(WS2812_DMA_STREAM
);
242 // NOTE: It's required that preload be enabled on the timer channel CCR register. This is currently enabled in the
243 // ChibiOS driver code, so we don't have to do anything special to the timer. If we did, we'd have to start the timer,
244 // disable counting, enable the channel, and then make whatever configuration changes we need.
245 pwmStart(&WS2812_PWMD
, &ws2812_pwm_config
);
246 pwmEnableChannel(&WS2812_PWMD
, WS2812_TIM_CH
, 0); // Initial period is 0; output will be low until first duty cycle is DMA'd in
249 ws2812_err_t
ws2812_write_led(uint32_t led_number
, uint8_t r
, uint8_t g
, uint8_t b
)
251 // Check for valid LED
252 if (led_number
> WS2812_LED_N
) return WS2812_LED_INVALID
;
254 // Write color to frame buffer
255 for (uint32_t bit
= 0; bit
< 8; bit
++) {
256 ws2812_frame_buffer
[WS2812_RED_BIT(led_number
, bit
)] = ((r
>> bit
) & 0x01) ? WS2812_DUTYCYCLE_1
: WS2812_DUTYCYCLE_0
;
257 ws2812_frame_buffer
[WS2812_GREEN_BIT(led_number
, bit
)] = ((g
>> bit
) & 0x01) ? WS2812_DUTYCYCLE_1
: WS2812_DUTYCYCLE_0
;
258 ws2812_frame_buffer
[WS2812_BLUE_BIT(led_number
, bit
)] = ((b
>> bit
) & 0x01) ? WS2812_DUTYCYCLE_1
: WS2812_DUTYCYCLE_0
;
262 return WS2812_SUCCESS
;
265 void ws2812_setleds(LED_TYPE
*ledarray
, uint16_t number_of_leds
)
267 for(int i
= 0; i
< number_of_leds
; i
++) {
268 ws2812_write_led(i
, ledarray
[i
].r
, ledarray
[i
].g
, ledarray
[i
].b
);
272 /** @} addtogroup WS2812 */