piolib: Add rxsource

Author: pelwell

piolib/examples/CMakeLists.txt

@@ -65,6 +65,11 @@ target_include_directories(blockingtest PRIVATE ../include)
 target_link_libraries(blockingtest pio pthread)
 install(TARGETS blockingtest RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 
+add_executable(rxsource rxsource.c)
+target_include_directories(rxsource PRIVATE ../include)
+target_link_libraries(rxsource pio)
+install(TARGETS rxsource RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
+
 add_executable(irqtest irqtest.c)
 target_include_directories(irqtest PRIVATE ../include ../../pinctrl)
 target_link_libraries(irqtest pio gpiolib)

piolib/examples/rxsource.c

@@ -0,0 +1,57 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "pico/stdlib.h"
+#include "hardware/pio.h"
+#include "rxsource.pio.h"
+
+#define DATA_WORDS 16
+
+int main(__unused int argc, __unused const char **argv) {
+    uint32_t databuf[DATA_WORDS];
+    uint gpio = 2;
+    int ret = 0;
+    int i, j;
+    stdio_init_all();
+
+    PIO pio = pio0;
+    int sm = pio_claim_unused_sm(pio, true);
+    uint offset = pio_add_program(pio, &rxsource_program);
+    printf("Loaded program at %d, using sm %d, gpio %d\n", offset, sm, gpio);
+
+    pio_sm_config_xfer(pio, sm, PIO_DIR_FROM_SM, sizeof(databuf), 4);
+
+    pio_gpio_init(pio, gpio);
+    pio_sm_set_consecutive_pindirs(pio, sm, gpio, 1, true);
+    pio_sm_config c = rxsource_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, gpio);
+    sm_config_set_clkdiv(&c, 1);
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+
+    // Read ahead as much as possible
+    for (j = 0; j < 4; j++) {
+        ret = pio_sm_xfer_data(pio, sm, PIO_DIR_FROM_SM, sizeof(databuf), NULL);
+        if (ret)
+            break;
+    }
+    for (i = 0; i < 1000; i++) {
+        ret = pio_sm_xfer_data(pio, sm, PIO_DIR_FROM_SM, sizeof(databuf), databuf);
+        if (ret)
+            break;
+        if (j < 1000) {
+            pio_sm_xfer_data(pio, sm, PIO_DIR_FROM_SM, sizeof(databuf), NULL);
+            j++;
+        }
+    }
+
+    if (ret)
+        printf("* error %d\n", ret);
+    return ret;
+}

piolib/examples/rxsource.pio

@@ -0,0 +1,5 @@
+.program rxsource
+.side_set 1
+
+    push                    side 0x1
+    nop                     side 0x0

piolib/examples/rxsource.pio.h

@@ -0,0 +1,44 @@
+// ---------------------------------------------------------------- //
+// This file is autogenerated by pioasm version 2.2.0; do not edit! //
+// ---------------------------------------------------------------- //
+
+#pragma once
+
+#if !PICO_NO_HARDWARE
+#include "hardware/pio.h"
+#endif
+
+// -------- //
+// rxsource //
+// -------- //
+
+#define rxsource_wrap_target 0
+#define rxsource_wrap 1
+#define rxsource_pio_version 0
+
+static const uint16_t rxsource_program_instructions[] = {
+            //     .wrap_target
+    0x9020, //  0: push   block           side 1
+    0xa042, //  1: nop                    side 0
+            //     .wrap
+};
+
+#if !PICO_NO_HARDWARE
+static const struct pio_program rxsource_program = {
+    .instructions = rxsource_program_instructions,
+    .length = 2,
+    .origin = -1,
+    .pio_version = rxsource_pio_version,
+#if PICO_PIO_VERSION > 0
+    .used_gpio_ranges = 0x0
+#endif
+};
+
+static inline pio_sm_config rxsource_program_get_default_config(uint offset) {
+    pio_sm_config c = pio_get_default_sm_config();
+    sm_config_set_wrap(&c, offset + rxsource_wrap_target, offset + rxsource_wrap);
+    sm_config_set_sideset(&c, 1, false, false);
+    return c;
+}
+#endif
+