add adc_dma_chain

apps/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(iperf_server)
-add_subdirectory(tcp_server)
+add_subdirectory(tcp_server)
+add_subdirectory(adc_dma_chain)

apps/adc_dma_chain/CMakeLists.txt

@@ -0,0 +1,24 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(adc-dma-chain)
+
+add_executable(adc_dma_chain
+    main.c
+)
+
+target_link_libraries(adc_dma_chain
+    pico_stdlib
+    pico_stdio
+    hardware_adc
+    hardware_dma
+    hardware_irq
+)
+
+target_include_directories(adc_dma_chain PRIVATE .)
+
+pico_enable_stdio_usb(adc_dma_chain 1)
+pico_enable_stdio_uart(adc_dma_chain 0)
+
+pico_add_extra_outputs(adc_dma_chain)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

apps/adc_dma_chain/main.c

@@ -0,0 +1,103 @@
+#include <stdio.h>
+#include "pico/stdlib.h"
+#include "hardware/adc.h"
+#include "hardware/dma.h"
+#include "hardware/irq.h"
+
+#define CAPTURE_CHANNEL 4
+#define CAPTURE_DEPTH 10000
+
+uint dma_chan_a, dma_chan_b;
+uint8_t capture_buf_a[CAPTURE_DEPTH];
+uint8_t capture_buf_b[CAPTURE_DEPTH];
+
+void dma_handler(uint8_t* buffer, int id) {
+    printf("DMA IRQ %d [%d %d %d]\n", id, buffer[0], buffer[1], buffer[2]);
+}
+
+void dma_handler_a() {
+    dma_handler((uint8_t*)&capture_buf_a, 0);
+    dma_hw->ints0 = 1u << dma_chan_a;
+    dma_channel_set_write_addr(dma_chan_a, &capture_buf_a, false);
+}
+
+void dma_handler_b() {
+    dma_handler((uint8_t*)&capture_buf_b, 1);
+    dma_hw->ints1 = 1u << dma_chan_b;
+    dma_channel_set_write_addr(dma_chan_b, &capture_buf_b, false);
+}
+
+int main() {
+    stdio_init_all();
+
+    getchar();
+    printf("Hello from Pi Pico!\n");
+
+    adc_gpio_init(26 + CAPTURE_CHANNEL);
+    adc_init();
+    adc_select_input(CAPTURE_CHANNEL);
+    adc_fifo_setup(
+        true,   // Write to FIFO
+        true,   // Enable DREQ
+        1,      // Trigger DREQ with at least one sample
+        false,  // No ERR bit
+        true    // Shift each sample by 8 bits
+    );
+    adc_set_clkdiv(0);
+
+    printf("Arming DMA.\n");
+    dma_channel_config dma_cfg_a, dma_cfg_b;
+
+    dma_chan_a = dma_claim_unused_channel(true);
+    dma_chan_b = dma_claim_unused_channel(true);
+
+    dma_cfg_a = dma_channel_get_default_config(dma_chan_a);
+    dma_cfg_b = dma_channel_get_default_config(dma_chan_b);
+
+    channel_config_set_transfer_data_size(&dma_cfg_a, DMA_SIZE_8);
+    channel_config_set_transfer_data_size(&dma_cfg_b, DMA_SIZE_8);
+
+    channel_config_set_read_increment(&dma_cfg_a, false);
+    channel_config_set_read_increment(&dma_cfg_b, false);
+
+    channel_config_set_write_increment(&dma_cfg_a, true);
+    channel_config_set_write_increment(&dma_cfg_b, true);
+
+    channel_config_set_dreq(&dma_cfg_a, DREQ_ADC);
+    channel_config_set_dreq(&dma_cfg_b, DREQ_ADC);
+
+    channel_config_set_chain_to(&dma_cfg_a, dma_chan_b);
+    channel_config_set_chain_to(&dma_cfg_b, dma_chan_a);
+
+    dma_channel_configure(dma_chan_a, &dma_cfg_a,
+        capture_buf_a,  // dst
+        &adc_hw->fifo,  // src
+        CAPTURE_DEPTH,  // transfer count
+        true            // start now
+    );
+
+    dma_channel_configure(dma_chan_b, &dma_cfg_b,
+        capture_buf_b,  // dst
+        &adc_hw->fifo,  // src
+        CAPTURE_DEPTH,  // transfer count
+        false           // start now
+    );
+
+    dma_channel_set_irq0_enabled(dma_chan_a, true);
+    irq_set_exclusive_handler(DMA_IRQ_0, dma_handler_a);
+    irq_set_enabled(DMA_IRQ_0, true);
+
+    dma_channel_set_irq1_enabled(dma_chan_b, true);
+    irq_set_exclusive_handler(DMA_IRQ_1, dma_handler_b);
+    irq_set_enabled(DMA_IRQ_1, true);
+
+    printf("Start capture.\n");
+    adc_run(true);
+
+    while (true)
+        tight_loop_contents();
+
+    printf("Bye from pico!\n\n");
+
+    return 0;
+}

apps/tcp_server/main.c

@@ -232,15 +232,9 @@ static void udpecho_raw_recv(void *arg, struct udp_pcb *pcb, struct pbuf *p, str
 	if(p == NULL)
 		return;
 
-    struct pbuf *pr;
-    uint8_t buf[4];
+    *(char*)(p->payload + 1) = '0';
 
-    pr = pbuf_alloc(PBUF_TRANSPORT, 4, PBUF_POOL);
-    pr->len = 4;
-    pr->tot_len = 4;
-    pr->payload = buf;
-
-	udp_sendto(pcb, pr, addr, port);
+	udp_sendto(pcb, p, addr, port);
 	pbuf_free(p);
 }