Add bare metal test for UART.

bare_metal_tests/.mbedignore

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+*

bare_metal_tests/uart/main.cpp

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+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "drivers/RawSerial.h"
+
+using namespace mbed;
+
+/* UART TEST FOR GREEN TEA
+ *
+ * Greentea-client uses RawSerial class to handle UART communication.
+ * RawSerial class must provide valid implementation of the following
+ * methods (used by Greentea-client):
+ * - int RawSerial::getc()
+ * - int RawSerial::putc(int c).
+ *
+ * Greentea-client uses USB serial port for communication with the
+ * following transmission parameters:
+ * - 8 data bits,
+ * - 1 stop bit,
+ * - none parity bit,
+ * - configurable baudrate.
+ *
+ * Greentea-client operates in pooling mode only.
+ * Flow control is disabled.
+ *
+ * UART buffer size is limited to 120 bytes.
+ *
+ * TEST SCENARIO
+ * This part of the test is executed on mbed board.
+ *
+ * After startup it will try to communicate via UART with host part of the test.
+ * This part sends 4 messages with different length to the host and waits
+ * for the response (host should respond with the same message).
+ * Last message "PASSED" is send to inform that all responses from host were
+ * successfully received.
+ *
+ * To perform this test with serial port baud rate different than default (9600),
+ * call host test with appropriate --baudrate parameter.
+ *
+ */
+
+/* Default baud rate if undefined. */
+#ifndef BAUD_RATE
+#define BAUD_RATE 9600
+#endif
+
+#define NUMBER_OF_TEST_STRINGS 5
+#define NUMBER_OF_TEST_RETRIES 10
+
+typedef enum
+{
+ PASSED, FAILED
+} test_status;
+
+/* Array of string to be transmitted. */
+const char *test_strings[NUMBER_OF_TEST_STRINGS] =
+ { "x",
+ "mbed", "Green Tea UART bare metal test.",
+ "Long Message-Long Message-Long Message-Long Message-Long Message-Long Message-Long Message-Long Message-Long Message--.",
+ "PASSED" };
+
+/* Function writes provided string to the serial port. */
+void write_line(RawSerial &serial, const char *str)
+{
+ while (true) {
+ serial.putc(*str);
+ if (*str == '\0') {
+ break;
+ }
+
+ str++;
+ };
+}
+
+/* Function reads provided string from the serial port. */
+int read_line(RawSerial &serial, char *buffer)
+{
+ int count = 0;
+ while (true) {
+ *buffer = (char) serial.getc();
+ count++;
+ if (*buffer == '\0') {
+ return count;
+ }
+
+ buffer += 1;
+ }
+}
+
+/* Function compares provided strings and returns 0 if are equal. */
+int strCmp(const char string1[], char string2[])
+{
+ for (int i = 0;; i++) {
+ if (string1[i] != string2[i]) {
+ return string1[i] < string2[i] ? -1 : 1;
+ }
+
+ if (string1[i] == '\0') {
+ return 0;
+ }
+ }
+}
+
+/* Function writes provided message to the serial port and
+ * waits for the response from the Host. Host should
+ * respond with the same message.
+ *
+ * If valid response has been received, then function returns
+ * PASSED status, otherwise transmission is repeated.
+ *
+ * If max number of transmission attempts is reached, then
+ * function returns FAILED status.
+ *
+ * */
+test_status test_uart_communication(RawSerial &serial, const char * msg)
+{
+ char buffer[120];
+
+ for (int i = 0; i < NUMBER_OF_TEST_RETRIES; i++) {
+ write_line(serial, msg);
+ read_line(serial, buffer);
+
+ if (strCmp(msg, buffer) == 0) {
+ return PASSED;
+ }
+ }
+
+ return FAILED;
+}
+
+int main()
+{
+ RawSerial serial(USBTX, USBRX, BAUD_RATE);
+
+ /* Start the test. */
+ for (unsigned int i = 0; i < (sizeof(test_strings) / sizeof(test_strings[0])); i++) {
+ if (test_uart_communication(serial, test_strings[i]) == FAILED) {
+ break;
+ }
+ }
+
+ while (true);
+}
+