Add stm32f411e-discovery example sound_out

Author: Kalle Raiskila

examples/stm32/f4/stm32f411e-discovery/README.md

@@ -0,0 +1,7 @@
+# README
+
+This directory contains samples for the STM32F411EDISCOVERY
+board. This is similar to the original STM32F4DISCOVERY, but
+has the the STM32F411VE MCU.
+The board is labeled 'MB-1115 B-02'
+

examples/stm32/f4/stm32f411e-discovery/sound_out/Makefile

@@ -0,0 +1,4 @@
+BINARY = sound_out
+DEVICE=STM32F411VE
+include ../../Makefile.include
+

examples/stm32/f4/stm32f411e-discovery/sound_out/README.md

@@ -0,0 +1,12 @@
+# README
+
+This example demonstrates using the oboard audio DAC on
+STM32F411-Discovery board.
+It plays a continuous 1 kHz sine wave.
+
+## Board connections
+
+Sepeakers attached to the 3.5mm audio jack.
+Note: volume is turned low, but beware of loud sounds
+in case of bugs (i.e. plug the headphones to your ear
+only after playback starts!)

examples/stm32/f4/stm32f411e-discovery/sound_out/sound_out.c

@@ -0,0 +1,154 @@
+/*
+ * Example to show using I2C and I2C with libopencm3.
+ * This is intended for the STM32F411-Discovery demoboard.
+ * It has a CS42L22 audio DAC onboard.
+ *
+ * The device plays a 1kHz sine through the audio jack.
+ */
+
+
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/i2c.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/spi.h>
+
+
+/* Test audio: 8 points of a sine.
+ * At Fs=8kHz, this means a 1kHz audio sine
+ * (the other channel is mute)
+ */
+#define VOL 0x0020
+#define D16(x) ((int16_t)(x*VOL) )
+//+ 0x7fff)
+int16_t audio[16]=
+{ D16(0),       0,
+  D16(0.70711), 0,
+  D16(1),       0,
+  D16(0.70711), 0,
+  D16(0),       0,
+  D16(-0.70711),0,
+  D16(-0.9999), 0,
+  D16(-0.707),  0 };
+
+
+static void write_i2c_to_audiochip( uint8_t reg, uint8_t contents)
+{
+	uint8_t packet[2];
+	packet[0] = reg;
+	packet[1] = contents;
+	/* STM32F411 gives device address with R/W bit,
+	 * libopencm wants it without it */
+	uint8_t address = (0x94)>>1;
+
+	i2c_transfer7(I2C1, address, packet, 2, NULL, 0);
+}
+
+int main(void)
+{
+	/* Set device clocks from opencm3 provided preset.*/
+	const struct rcc_clock_scale *clocks = &rcc_hsi_configs[RCC_CLOCK_3V3_84MHZ];
+	rcc_clock_setup_pll( clocks );
+
+	rcc_periph_clock_enable(RCC_GPIOA);
+	rcc_periph_clock_enable(RCC_GPIOB);
+	rcc_periph_clock_enable(RCC_GPIOC);
+	rcc_periph_clock_enable(RCC_GPIOD);
+
+	/* Initialize "heartbeat" LED GPIO */
+	gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO13);
+
+	/* I2C GPIO pins
+	 * PB6 - SCL (I2C clock)
+	 * PB9 - SDA (I2C data)
+	 * The board does not have pullups on the I2C lines, so
+	 * we use the chip internal pullups.
+	 * Also the pins must be open drain, as per I2C specification.
+	 * STM32F411 datasheet "Alternate Functions table" tells that
+	 * I2C is AlternateFucntion 4 for both pins.
+	 */
+	gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO6);
+	gpio_mode_setup(GPIOB, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO9);
+	gpio_set_output_options(GPIOB, GPIO_OTYPE_OD, GPIO_OSPEED_25MHZ, GPIO6);
+	gpio_set_output_options(GPIOB, GPIO_OTYPE_OD, GPIO_OSPEED_25MHZ, GPIO9);
+	gpio_set_af(GPIOB, GPIO_AF4, GPIO6);
+	gpio_set_af(GPIOB, GPIO_AF4, GPIO9);
+
+	/* Initialize the I2C itself.
+	 * Since we are master, we would not need to initialize slave
+	 * address, but this is the only libopencm3 API call that sets
+	 * the 'bit14 of CCR' - a bit in the I2C that is HW reset to 0,
+	 * but manual says 'must be 1' */
+	rcc_periph_clock_enable(RCC_I2C1);
+	i2c_peripheral_disable(I2C1);
+	i2c_set_speed(I2C1, i2c_speed_sm_100k, clocks->apb1_frequency/1000000);
+	i2c_set_own_7bit_slave_address(I2C1, 0);
+	i2c_peripheral_enable(I2C1);
+
+	/* Initialize I2S.
+	 * I2S is implemented as a HW mode of the SPI peripheral.
+	 * Since this is a STM32F411, there is a separate I2S PLL
+	 * that needs to be enabled.
+	 */
+	rcc_osc_on(RCC_PLLI2S);
+	rcc_periph_clock_enable(RCC_SPI3);
+	i2s_disable(SPI3);
+	i2s_set_standard(SPI3, i2s_standard_philips);
+	i2s_set_dataformat(SPI3, i2s_dataframe_ch16_data16);
+	i2s_set_mode(SPI3, i2s_mode_master_transmit);
+	i2s_masterclock_enable(SPI3);
+	/* RCC_PLLI2SCFGR configured values are:
+	 * 0x24003010 i.e.
+	 * PLLR = 2
+	 * PLLI2SN = 192
+	 * PLLI2SM = 16
+	 * And since the input is PLL source (i.e. HSI = 16MHz)
+	 * The I2S clock = 16 / 16 * 192 / 2 = 96MHz
+	 * Calculate sampling frequency from equation given in
+	 * STM32F411 reference manual:
+	 * Fs = I2Sclk/ (32*2 * ((2*I2SDIV)+ODD)*4)
+	 * I2SDIV = I2Sclk/(512*Fs)
+	 * I2SDIV=24 => 23,4 so 23 + ODD bit set
+	 */
+	i2s_set_clockdiv(SPI3, 23, 1);
+	i2s_enable(SPI3);
+
+
+	/* I2S pins:
+	 * Master clock: PC7
+	 * Bit clock: PC10
+	 * Data: PC12
+	 * L/R clock: PA4
+	 */
+	gpio_mode_setup(GPIOC, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO7);
+	gpio_set_af(GPIOC, GPIO_AF6, GPIO7);
+	gpio_mode_setup(GPIOC, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO10);
+	gpio_set_af(GPIOC, GPIO_AF6, GPIO10);
+	gpio_mode_setup(GPIOC, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO12);
+	gpio_set_af(GPIOC, GPIO_AF6, GPIO12);
+	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO4);
+	gpio_set_af(GPIOA, GPIO_AF6, GPIO4);
+
+
+	/* Initialize the Audio DAC, as per its datasheet.
+	 * CS43L22 /RESET is connected to PD4, first release it. Then write
+	 * minimum set of needed settings. */
+	gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO4);
+	gpio_set(GPIOD, GPIO4);
+	write_i2c_to_audiochip(0x06, 0x04); // interface control 1: set I2S dataformat
+	write_i2c_to_audiochip(0x02, 0x9e); // power control 1: Magic value to power up the chip
+
+
+	while(1) {
+		/* Blink the heartbeat LED */
+		static int blinkslowdown=0;
+		if( ++blinkslowdown == 8000) {
+			gpio_toggle(GPIOD, GPIO13);
+			blinkslowdown=0;
+		}
+
+		for( unsigned i=0; i < sizeof(audio)/sizeof(audio[0]); i++)
+			spi_send(SPI3, audio[i]);
+	}
+	return 0;
+}
+