238 lines
6.7 KiB
C
238 lines
6.7 KiB
C
/**
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* @file main.c
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* @author giomba@glgprograms.it
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* @brief
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*
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* @copyright Copyright Retrofficina GLG Programs (c) 2022
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*
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*/
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#include "hardware/clocks.h"
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#include "hardware/dma.h"
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#include "hardware/pio.h"
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#include "hardware/pll.h"
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#include "hardware/structs/pio.h"
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#include "pico/stdlib.h"
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include "vga.pio.h"
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#define FRAMES 2
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#define HPIXEL 640
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#define VPIXEL 480
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#define BPP 1
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typedef struct Frame
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{
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uint8_t data[HPIXEL * VPIXEL * BPP / 8];
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} Frame;
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static Frame frames[FRAMES] = {0};
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static void vga_pixel_program_init(PIO pio, uint sm, uint offset)
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{
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// magic definition of the called function?
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pio_sm_config config = vga_free_run_program_get_default_config(offset);
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// destination pins for OUT instructions
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sm_config_set_out_pins(&config, 22, 1);
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sm_config_set_out_shift(&config, true, true, 0);
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pio_gpio_init(pio, 22);
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pio_sm_set_consecutive_pindirs(pio, sm, 22, 1, true);
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pio_sm_init(pio, sm, offset, &config);
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pio_sm_set_clkdiv_int_frac(pio, sm, 1, 0);
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pio_sm_set_enabled(pio, sm, true);
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}
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static void vga_hsync_program_init(PIO pio, uint sm, uint offset)
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{
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pio_sm_config config = vga_hsync_program_get_default_config(offset);
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// destination pins for SET instructions
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sm_config_set_set_pins(&config, 20, 1);
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pio_gpio_init(pio, 20);
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pio_sm_set_consecutive_pindirs(pio, sm, 20, 1, true);
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pio_sm_init(pio, sm, offset, &config);
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pio_sm_set_clkdiv_int_frac(pio, sm, 1, 0);
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pio->sm->shiftctrl = (1 << PIO_SM0_SHIFTCTRL_FJOIN_TX_LSB);
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pio_sm_set_enabled(pio, sm, true);
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}
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static void vga_vsync_program_init(PIO pio, uint sm, uint offset)
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{
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pio_sm_config config = vga_vsync_program_get_default_config(offset);
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// destination pins for SET instructions
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sm_config_set_set_pins(&config, 21, 1);
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pio_gpio_init(pio, 21);
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pio_sm_set_consecutive_pindirs(pio, sm, 21, 1, true);
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pio_sm_init(pio, sm, offset, &config);
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pio_sm_set_clkdiv_int_frac(pio, sm, 1, 0);
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pio->sm->shiftctrl = (1 << PIO_SM0_SHIFTCTRL_FJOIN_TX_LSB);
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pio_sm_set_enabled(pio, sm, true);
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}
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void setup_clocks(void)
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{
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// disable resuscitation clock
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clocks_hw->resus.ctrl = 0;
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// before changing PLL, switch sys and ref cleanly away from their aux sources
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hw_clear_bits(&clocks_hw->clk[clk_sys].ctrl, CLOCKS_CLK_SYS_CTRL_SRC_BITS);
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while (clocks_hw->clk[clk_sys].selected != 0x1)
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tight_loop_contents();
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hw_clear_bits(&clocks_hw->clk[clk_ref].ctrl, CLOCKS_CLK_REF_CTRL_SRC_BITS);
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while (clocks_hw->clk[clk_ref].selected != 0x1)
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tight_loop_contents();
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// set PLL at 126 MHz, and wait for it to stabilize
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pll_init(pll_sys, 1, 1512 * MHZ, 6, 2);
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// re-configure sys_clk to use PLL
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clock_configure(clk_sys, CLOCKS_CLK_SYS_CTRL_SRC_VALUE_CLKSRC_CLK_SYS_AUX,
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CLOCKS_CLK_SYS_CTRL_AUXSRC_VALUE_CLKSRC_PLL_SYS, 126 * MHZ, 126 * MHZ);
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// re-configure CLK PERI = clk_sys
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clock_configure(clk_peri, 0, CLOCKS_CLK_PERI_CTRL_AUXSRC_VALUE_CLK_SYS, 126 * MHZ, 126 * MHZ);
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}
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static bool dma_ready = false;
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static int dma_channel;
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void new_frame_handler(void)
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{
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// restart DMA
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if (dma_ready)
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dma_channel_set_read_addr(dma_channel, &frames[0].data[0], true);
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pio_interrupt_clear(pio0_hw, 1);
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}
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void dma_handler(void)
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{
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// acknoweledge DMA
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dma_hw->ints0 = 1 << dma_channel;
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}
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void set_pixel(uint16_t x, uint16_t y)
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{
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frames[0].data[y * 80 + x / 8] |= (1 << x % 8);
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}
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/**
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* @brief Represents a program running on the SM of a PIO.
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*
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*/
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typedef struct PIORun
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{
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PIO pio; //< executing PIO
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uint offset; //< PIO memory offset for program
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uint sm; //< executing SM
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} PIORun;
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int main()
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{
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setup_clocks();
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stdio_init_all();
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sleep_ms(1000);
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// clear frame buffer
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memset(&frames[0].data[0], 0, sizeof(frames[0].data));
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// draw a cross
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// horizontal lines
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for (uint16_t x = 0; x < 639; ++x) // last pixel high -> bad
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{
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set_pixel(x, 0);
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set_pixel(x, 239);
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set_pixel(x, 479);
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}
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// vertical lines
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for (uint16_t y = 0; y < 480; ++y)
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{
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set_pixel(0, y);
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set_pixel(239, y);
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set_pixel(638, y);
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}
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// Running programs on PIO
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PIORun vga_hsync, vga_vsync, vga_pixel;
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vga_hsync.pio = vga_vsync.pio = vga_pixel.pio = pio0;
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// Prepare frame interrupt
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// Frame interrupt is asserted on PIO0 interrupt 1 by SM1
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pio_set_irq1_source_enabled(vga_vsync.pio, pis_interrupt1,
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true); // allow SM1 of PIO to fire the interrupt
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irq_set_exclusive_handler(PIO0_IRQ_1, new_frame_handler); // set handler for IRQ1 of PIO
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irq_set_enabled(PIO0_IRQ_1, true); // enable interrupt
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// VGA HSYNC program
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printf("Starting VGA hsync machine... ");
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if (!pio_can_add_program(vga_hsync.pio, &vga_hsync_program))
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panic("cannot add program");
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vga_hsync.offset = pio_add_program(vga_hsync.pio, &vga_hsync_program);
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vga_hsync.sm = pio_claim_unused_sm(vga_hsync.pio, true);
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vga_hsync_program_init(vga_hsync.pio, vga_hsync.sm, vga_hsync.offset);
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// low pulse is X pixels long, and SM runs at 4x of pixel clock
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pio_sm_put_blocking(vga_hsync.pio, vga_hsync.sm, (64 - 1) * 4);
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pio_sm_put_blocking(vga_hsync.pio, vga_hsync.sm, (776 - 1) * 4);
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printf("OK\n");
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// VGA VSYNC program
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printf("Starting VGA vsync machine... ");
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if (!pio_can_add_program(vga_vsync.pio, &vga_vsync_program))
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panic("cannot add program");
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vga_vsync.offset = pio_add_program(vga_vsync.pio, &vga_vsync_program);
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vga_vsync.sm = pio_claim_unused_sm(vga_vsync.pio, true);
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vga_vsync_program_init(vga_vsync.pio, vga_vsync.sm, vga_vsync.offset);
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// low pulse assert lasts for 3 horizontal lines, then adjust by one
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pio_sm_put_blocking(vga_vsync.pio, vga_vsync.sm, 3 - 1);
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pio_sm_put_blocking(vga_vsync.pio, vga_vsync.sm, 500 - 3 - 1);
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printf("OK\n");
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// VGA pixel program
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printf("Starting VGA pixel machine... ");
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if (!pio_can_add_program(vga_pixel.pio, &vga_free_run_program))
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panic("cannot add program");
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vga_pixel.offset = pio_add_program(vga_pixel.pio, &vga_free_run_program);
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vga_pixel.sm = pio_claim_unused_sm(vga_pixel.pio, false);
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vga_pixel_program_init(vga_pixel.pio, vga_pixel.sm, vga_pixel.offset);
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pio_sm_put_blocking(vga_pixel.pio, vga_pixel.sm, 640 - 1);
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printf("OK\n");
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printf("Setting up DMA... ");
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dma_channel = dma_claim_unused_channel(true);
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dma_channel_config dma_config = dma_channel_get_default_config(dma_channel);
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channel_config_set_transfer_data_size(&dma_config, DMA_SIZE_32);
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channel_config_set_read_increment(&dma_config, true);
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channel_config_set_write_increment(&dma_config, false);
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channel_config_set_dreq(&dma_config, DREQ_PIO0_TX2);
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dma_channel_set_irq0_enabled(dma_channel, true);
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irq_set_exclusive_handler(DMA_IRQ_0, dma_handler);
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irq_set_enabled(DMA_IRQ_0, true);
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dma_channel_configure(dma_channel, &dma_config, &pio0_hw->txf[2], &frames[0].data[0], 9600,
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false);
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dma_ready = true;
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printf("OK\n");
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printf("Now running.\n");
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for (;;)
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tight_loop_contents();
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}
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