1 files changed, 194 insertions, 0 deletions
diff --git a/examples/test-spi-roundtrip.cpp b/examples/test-spi-roundtrip.cpp
new file mode 100644
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--- /dev/null
+++ b/examples/test-spi-roundtrip.cpp
@@ -0,0 +1,194 @@
+/*
+ * Polling SPI loopback test.
+ *
+ * Bob is nowhere to be found, so Alice decides to talk to herself.
+ *
+ * Instructions: Connect SPI2 (Alice) to herself (i.e., MISO to MOSI).
+ * Connect to Alice via SerialUSB.  Press any key to start.
+ *
+ * Alice will talk to herself for a little while.  The sketch will
+ * report if Alice can't hear anything she says.  She'll then start
+ * talking forever at various frequencies, bit orders, and modes.  Use
+ * an oscilloscope to make sure she's not trying to lie about any of
+ * those things.
+ *
+ * This file is released into the public domain.
+ *
+ * Author: Marti Bolivar <mbolivar@leaflabs.com>
+ */
+
+#include "wirish.h"
+
+HardwareSPI alice(2);
+
+#define NFREQS 8
+const SPIFrequency spi_freqs[] = {
+    SPI_140_625KHZ,
+    SPI_281_250KHZ,
+    SPI_562_500KHZ,
+    SPI_1_125MHZ,
+    SPI_2_25MHZ,
+    SPI_4_5MHZ,
+    SPI_9MHZ,
+    SPI_18MHZ,
+};
+
+#define TEST_BUF_SIZE 10
+uint8 test_buf[TEST_BUF_SIZE] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+
+void bad_assert(const char* file, int line, const char* exp) {
+    SerialUSB.println();
+    SerialUSB.print("ERROR: FAILED ASSERT(");
+    SerialUSB.print(exp);
+    SerialUSB.print("): ");
+    SerialUSB.print(file);
+    SerialUSB.print(": ");
+    SerialUSB.println(line);
+    throb();
+}
+
+#undef ASSERT
+#define ASSERT(exp)                                    \
+    if (exp) {                                         \
+    } else {                                           \
+        bad_assert(__FILE__, __LINE__, #exp);          \
+    }
+
+void haveConversation(uint32 bitOrder);
+void soliloquies(uint32 bitOrder);
+
+void setup() {
+    pinMode(BOARD_LED_PIN, OUTPUT);
+    while (!SerialUSB.available())
+        ;
+    SerialUSB.read();
+}
+
+void loop() {
+    SerialUSB.println("** Having a conversation, MSB first");
+    haveConversation(MSBFIRST);
+
+    SerialUSB.println("** Having a conversation, LSB first");
+    haveConversation(LSBFIRST);
+
+    SerialUSB.println();
+    SerialUSB.println("*** All done!  It looks like everything worked.");
+    SerialUSB.println();
+
+    SerialUSB.println("** Alice will now wax eloquent in various styles. "
+                    "Press any key for the next configuration.");
+    soliloquies(MSBFIRST);
+    soliloquies(LSBFIRST);
+
+    while (true)
+        ;
+}
+
+void printFrequencyString(SPIFrequency frequency);
+void chat(SPIFrequency frequency, uint32 bitOrder, uint32 mode);
+
+void haveConversation(uint32 bitOrder) {
+    for (int f = 0; f < NFREQS; f++) {
+        for (int mode = 0; mode < 4; mode++) {
+            chat(spi_freqs[f], bitOrder, mode);
+            delay(10);
+        }
+    }
+}
+
+void chat(SPIFrequency frequency, uint32 bitOrder, uint32 mode) {
+    SerialUSB.print("Having a chat.\tFrequency: ");
+    printFrequencyString(frequency);
+    SerialUSB.print(",\tbitOrder: ");
+    SerialUSB.print(bitOrder == MSBFIRST ? "MSB" : "LSB");
+    SerialUSB.print(",\tmode: ");
+    SerialUSB.print(mode);
+    SerialUSB.print(".");
+
+    SerialUSB.print(" [1] ");
+    alice.begin(frequency, bitOrder, mode);
+
+    SerialUSB.print(" [2] ");
+    uint32 txed = 0;
+    while (txed < TEST_BUF_SIZE) {
+        ASSERT(alice.transfer(test_buf[txed]) == test_buf[txed]);
+        txed++;
+    }
+
+    SerialUSB.print(" [3] ");
+    alice.end();
+
+    SerialUSB.println(" ok.");
+}
+
+void soliloquy(SPIFrequency freq, uint32 bitOrder, uint32 mode);
+
+void soliloquies(uint32 bitOrder) {
+    for (int f = 0; f < NFREQS; f++) {
+        for (int mode = 0; mode < 4; mode++) {
+            soliloquy(spi_freqs[f], bitOrder, mode);
+        }
+    }
+}
+
+void soliloquy(SPIFrequency frequency, uint32 bitOrder, uint32 mode) {
+    const uint8 repeat = 0xAE;
+    SerialUSB.print("Alice is giving a soliloquy (repeating 0x");
+    SerialUSB.print(repeat, HEX);
+    SerialUSB.print("). Frequency: ");
+    printFrequencyString(frequency);
+    SerialUSB.print(", bitOrder: ");
+    SerialUSB.print(bitOrder == MSBFIRST ? "big-endian" : "little-endian");
+    SerialUSB.print(", SPI mode: ");
+    SerialUSB.println(mode);
+
+    alice.begin(frequency, bitOrder, mode);
+    while (!SerialUSB.available()) {
+        alice.write(repeat);
+        delayMicroseconds(200);
+    }
+    SerialUSB.read();
+}
+
+void printFrequencyString(SPIFrequency frequency) {
+    switch (frequency) {
+    case SPI_18MHZ:
+        SerialUSB.print("18 MHz");
+        break;
+    case SPI_9MHZ:
+        SerialUSB.print("9 MHz");
+        break;
+    case SPI_4_5MHZ:
+        SerialUSB.print("4.5 MHz");
+        break;
+    case SPI_2_25MHZ:
+        SerialUSB.print("2.25 MHZ");
+        break;
+    case SPI_1_125MHZ:
+        SerialUSB.print("1.125 MHz");
+        break;
+    case SPI_562_500KHZ:
+        SerialUSB.print("562.500 KHz");
+        break;
+    case SPI_281_250KHZ:
+        SerialUSB.print("281.250 KHz");
+        break;
+    case SPI_140_625KHZ:
+        SerialUSB.print("140.625 KHz");
+        break;
+    }
+}
+
+// Force init to be called *first*, i.e. before static object allocation.
+// Otherwise, statically allocated objects that need libmaple may fail.
+__attribute__((constructor)) void premain() {
+    init();
+}
+
+int main(void) {
+    setup();
+    while (true) {
+        loop();
+    }
+    return 0;
+}