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new 11f2d5e5e examples/rmtchar: Implement RX and/or TX using the RMT char
driver
11f2d5e5e is described below
commit 11f2d5e5e4c0937afa0db2f27d1c664bd7ba4706
Author: Tiago Medicci Serrano <[email protected]>
AuthorDate: Tue Nov 28 12:41:05 2023 -0300
examples/rmtchar: Implement RX and/or TX using the RMT char driver
The RMT (remote control) character driver is used to send and/or
receive data packets. Eventually, this app can be used to perform
a loopback test to validate the RMT driver implementation.
---
examples/rmtchar/CMakeLists.txt | 38 ++++
examples/rmtchar/Kconfig | 68 +++++++
examples/rmtchar/Make.defs | 23 +++
examples/rmtchar/Makefile | 41 ++++
examples/rmtchar/rmtchar.h | 127 ++++++++++++
examples/rmtchar/rmtchar_common.c | 91 +++++++++
examples/rmtchar/rmtchar_main.c | 360 +++++++++++++++++++++++++++++++++
examples/rmtchar/rmtchar_receiver.c | 138 +++++++++++++
examples/rmtchar/rmtchar_transmitter.c | 156 ++++++++++++++
9 files changed, 1042 insertions(+)
diff --git a/examples/rmtchar/CMakeLists.txt b/examples/rmtchar/CMakeLists.txt
new file mode 100644
index 000000000..0adae0913
--- /dev/null
+++ b/examples/rmtchar/CMakeLists.txt
@@ -0,0 +1,38 @@
+#
##############################################################################
+# apps/examples/rmtchar/CMakeLists.txt
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
contributor
+# license agreements. See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership. The ASF licenses this
+# file to you 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.
+#
+#
##############################################################################
+
+if(CONFIG_EXAMPLES_RMTCHAR)
+ nuttx_add_application(
+ NAME
+ rmtchar
+ STACKSIZE
+ ${CONFIG_DEFAULT_TASK_STACKSIZE}
+ MODULE
+ ${CONFIG_EXAMPLES_RMTCHAR}
+ SRCS
+ rmtchar_common.c
+ rmtchar_main.c)
+ if(CONFIG_EXAMPLES_RMTCHAR_TX)
+ target_sources(apps PRIVATE rmtchar_transmitter.c)
+ endif()
+ if(CONFIG_EXAMPLES_RMTCHAR_RX)
+ target_sources(apps PRIVATE rmtchar_receiver.c)
+ endif()
+endif()
diff --git a/examples/rmtchar/Kconfig b/examples/rmtchar/Kconfig
new file mode 100644
index 000000000..8831f56a2
--- /dev/null
+++ b/examples/rmtchar/Kconfig
@@ -0,0 +1,68 @@
+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config EXAMPLES_RMTCHAR
+ tristate "RMT character driver test"
+ default n
+ depends on RMT
+ ---help---
+ Enable the RMT character driver test
+
+if EXAMPLES_RMTCHAR
+
+config EXAMPLES_RMTCHAR_TX
+ bool "Use RMT transmitter"
+ default n
+ ---help---
+ This should be set if the RMT device supports a transmitter.
+
+if EXAMPLES_RMTCHAR_TX
+
+config EXAMPLES_RMTCHAR_TX_DEVPATH
+ string "RMT transmitter character device path"
+ default "/dev/rmt0"
+ ---help---
+ The default path to the RMT transmitter character device.
+ Default: /dev/rmt0
+
+config EXAMPLES_RMTCHAR_TXSTACKSIZE
+ int "Transmitter thread stack size"
+ default DEFAULT_TASK_STACKSIZE
+ ---help---
+ This is the stack size to use when starting the transmitter
thread.
+
+endif # EXAMPLES_RMTCHAR_TX
+
+config EXAMPLES_RMTCHAR_RX
+ bool "Use RMT receiver"
+ default n
+ ---help---
+ This should be set if the RMT device supports a receiver.
+
+if EXAMPLES_RMTCHAR_RX
+
+config EXAMPLES_RMTCHAR_RX_DEVPATH
+ string "RMT receiver character device path"
+ default "/dev/rmt1"
+ ---help---
+ The default path to the RMT receiver character device.
+ Default: /dev/rmt1
+
+config EXAMPLES_RMTCHAR_RXSTACKSIZE
+ int "Receiver thread stack size"
+ default DEFAULT_TASK_STACKSIZE
+ ---help---
+ This is the stack size to use when starting the receiver thread.
+
+endif # EXAMPLES_RMTCHAR_RX
+
+config EXAMPLES_RMTCHAR_ITEMS
+ int "Number of words to transmit or receive"
+ default 64
+ ---help---
+ This is the total amount of words to be transmitted or
+ received by the RMT RX device.
+
+endif
diff --git a/examples/rmtchar/Make.defs b/examples/rmtchar/Make.defs
new file mode 100644
index 000000000..e6550150c
--- /dev/null
+++ b/examples/rmtchar/Make.defs
@@ -0,0 +1,23 @@
+############################################################################
+# apps/examples/rmtchar/Make.defs
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership. The
+# ASF licenses this file to you 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.
+#
+############################################################################
+
+ifneq ($(CONFIG_EXAMPLES_RMTCHAR),)
+CONFIGURED_APPS += $(APPDIR)/examples/rmtchar
+endif
diff --git a/examples/rmtchar/Makefile b/examples/rmtchar/Makefile
new file mode 100644
index 000000000..342cb6ec4
--- /dev/null
+++ b/examples/rmtchar/Makefile
@@ -0,0 +1,41 @@
+############################################################################
+# apps/examples/rmtchar/Makefile
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more
+# contributor license agreements. See the NOTICE file distributed with
+# this work for additional information regarding copyright ownership. The
+# ASF licenses this file to you 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 $(APPDIR)/Make.defs
+
+# rmt character driver test
+
+ifeq ($(CONFIG_EXAMPLES_RMTCHAR_TX),y)
+CSRCS += rmtchar_transmitter.c
+endif
+ifeq ($(CONFIG_EXAMPLES_RMTCHAR_RX),y)
+CSRCS += rmtchar_receiver.c
+endif
+CSRCS += rmtchar_common.c
+MAINSRC = rmtchar_main.c
+
+# Touchscreen built-in application info
+
+PROGNAME = rmtchar
+PRIORITY = SCHED_PRIORITY_DEFAULT
+STACKSIZE = $(CONFIG_DEFAULT_TASK_STACKSIZE)
+MODULE = $(CONFIG_EXAMPLES_RMTCHAR)
+
+include $(APPDIR)/Application.mk
diff --git a/examples/rmtchar/rmtchar.h b/examples/rmtchar/rmtchar.h
new file mode 100644
index 000000000..2d89479bf
--- /dev/null
+++ b/examples/rmtchar/rmtchar.h
@@ -0,0 +1,127 @@
+/****************************************************************************
+ * apps/examples/rmtchar/rmtchar.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+#ifndef __APPS_EXAMPLES_RMTCHAR_RMTCHAR_H
+#define __APPS_EXAMPLES_RMTCHAR_RMTCHAR_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <pthread.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Configuration */
+
+#ifndef CONFIG_EXAMPLES_RMTCHAR_TX_DEVPATH
+# define CONFIG_EXAMPLES_RMTCHAR_TX_DEVPATH "/dev/rmt0"
+#endif
+
+#ifndef CONFIG_EXAMPLES_RMTCHAR_RX_DEVPATH
+# define CONFIG_EXAMPLES_RMTCHAR_RX_DEVPATH "/dev/rmt1"
+#endif
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+struct rmtchar_state_s
+{
+ bool initialized;
+ int rmtchar_items;
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ FAR char *txdevpath;
+#endif
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ FAR char *rxdevpath;
+#endif
+};
+
+struct rmt_item32_s
+{
+ union
+ {
+ struct
+ {
+ uint32_t duration0 : 15; /* Duration of level0 */
+ uint32_t level0 : 1; /* Level of the first part */
+ uint32_t duration1 : 15; /* Duration of level1 */
+ uint32_t level1 : 1; /* Level of the second part */
+ };
+ uint32_t val; /* Equivalent unsigned value for the RMT item */
+ };
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmtchar_transmitter()
+ *
+ * Description:
+ * This is the entry point for the transmitter thread.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+pthread_addr_t rmtchar_transmitter(pthread_addr_t arg);
+#endif
+
+/****************************************************************************
+ * Name: rmtchar_receiver()
+ *
+ * Description:
+ * This is the entry point for the receiver thread.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+pthread_addr_t rmtchar_receiver(pthread_addr_t arg);
+#endif
+
+/****************************************************************************
+ * Name: print_items
+ *
+ * Description:
+ * This function prints the level and duration of RMT items stored in a
+ * buffer. It iterates over the buffer, printing the level and duration of
+ * each item in a formatted manner.
+ *
+ * Input Parameters:
+ * buf - Pointer to the buffer containing the RMT items.
+ * len - The number of RMT items in the buffer.
+ *
+ * Returned Value:
+ * None.
+ *
+ ****************************************************************************/
+
+void print_items(struct rmt_item32_s *buf, int len);
+
+#endif /* __APPS_EXAMPLES_RMTCHAR_RMTCHAR_H */
diff --git a/examples/rmtchar/rmtchar_common.c
b/examples/rmtchar/rmtchar_common.c
new file mode 100644
index 000000000..f7d1a4d9d
--- /dev/null
+++ b/examples/rmtchar/rmtchar_common.c
@@ -0,0 +1,91 @@
+/****************************************************************************
+ * apps/examples/rmtchar/rmtchar_common.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <errno.h>
+#include <debug.h>
+#include <unistd.h>
+
+#include "rmtchar.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: print_items
+ *
+ * Description:
+ * This function prints the level and duration of RMT items stored in a
+ * buffer. It iterates over the buffer, printing the level and duration of
+ * each item in a formatted manner.
+ *
+ * Input Parameters:
+ * buf - Pointer to the buffer containing the RMT items.
+ * len - The number of RMT items in the buffer.
+ *
+ * Returned Value:
+ * None.
+ *
+ ****************************************************************************/
+
+void print_items(struct rmt_item32_s *buf, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++, buf++)
+ {
+ printf("\t[%d]:\tL %d\tD %d\t", i, buf->level0, buf->duration0);
+ printf("L %d\t D %d\n", buf->level1, buf->duration1);
+ }
+}
diff --git a/examples/rmtchar/rmtchar_main.c b/examples/rmtchar/rmtchar_main.c
new file mode 100644
index 000000000..d57c815be
--- /dev/null
+++ b/examples/rmtchar/rmtchar_main.c
@@ -0,0 +1,360 @@
+/****************************************************************************
+ * apps/examples/rmtchar/rmtchar_main.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pthread.h>
+#include <errno.h>
+#include <debug.h>
+
+#include "rmtchar.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#if !defined(CONFIG_EXAMPLES_RMTCHAR_RX) && \
+ !defined(CONFIG_EXAMPLES_RMTCHAR_TX)
+# error "At least one of CONFIG_EXAMPLES_RMTCHAR_RX or \
+ CONFIG_EXAMPLES_RMTCHAR_TX must be defined"
+#endif
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static struct rmtchar_state_s g_rmtchar;
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmtchar_devpath
+ ****************************************************************************/
+
+static void rmtchar_devpath(FAR struct rmtchar_state_s *rmtchar,
+ FAR const char *devpath,
+ bool is_tx)
+{
+ /* Get rid of any old device path */
+
+ if (is_tx)
+ {
+ if (rmtchar->txdevpath)
+ {
+ free(rmtchar->txdevpath);
+ }
+
+ /* Then set-up the new device path by copying the string */
+
+ rmtchar->txdevpath = strdup(devpath);
+ }
+ else
+ {
+ if (rmtchar->rxdevpath)
+ {
+ free(rmtchar->rxdevpath);
+ }
+
+ /* Then set-up the new device path by copying the string */
+
+ rmtchar->rxdevpath = strdup(devpath);
+ }
+}
+
+/****************************************************************************
+ * Name: rmtchar_help
+ ****************************************************************************/
+
+static void rmtchar_help(FAR struct rmtchar_state_s *rmtchar)
+{
+ printf("Usage: rmtchar [OPTIONS]\n");
+ printf("\nArguments are \"sticky\".\n");
+ printf("For example, once the RMT character device is\n");
+ printf("specified, that device will be re-used until it is changed.\n");
+ printf("\n\"sticky\" OPTIONS include:\n");
+ printf(" [-i items] selects the number of words (items) to be transmitted"
+ " or received by the RMT character device. "
+ "Default: %d Current: %d\n",
+ CONFIG_EXAMPLES_RMTCHAR_ITEMS,
+ rmtchar->rmtchar_items ? rmtchar->rmtchar_items :
+ CONFIG_EXAMPLES_RMTCHAR_ITEMS);
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ printf(" [-t devpath] selects the RMT transmitter character device path. "
+ "Default: %s Current: %s\n",
+ CONFIG_EXAMPLES_RMTCHAR_TX_DEVPATH,
+ rmtchar->txdevpath ? rmtchar->txdevpath : "NONE");
+#endif
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ printf(" [-r devpath] selects the RMT receiver character device path. "
+ "Default: %s Current: %s\n",
+ CONFIG_EXAMPLES_RMTCHAR_RX_DEVPATH,
+ rmtchar->rxdevpath ? rmtchar->rxdevpath : "NONE");
+#endif
+ printf(" [-h] shows this message and exits\n");
+}
+
+/****************************************************************************
+ * Name: arg_string
+ ****************************************************************************/
+
+static int arg_string(FAR char **arg, FAR char **value)
+{
+ FAR char *ptr = *arg;
+
+ if (ptr[2] == '\0')
+ {
+ *value = arg[1];
+ return 2;
+ }
+ else
+ {
+ *value = &ptr[2];
+ return 1;
+ }
+}
+
+/****************************************************************************
+ * Name: arg_decimal
+ ****************************************************************************/
+
+static int arg_decimal(FAR char **arg, FAR int *value)
+{
+ FAR char *string;
+ int ret;
+
+ ret = arg_string(arg, &string);
+ *value = strtol(string, NULL, 10);
+ return ret;
+}
+
+/****************************************************************************
+ * Name: parse_args
+ ****************************************************************************/
+
+static void parse_args(FAR struct rmtchar_state_s *rmtchar,
+ int argc,
+ FAR char **argv)
+{
+ FAR char *ptr;
+ FAR char *str;
+ int value;
+ int index;
+ int nargs;
+
+ for (index = 1; index < argc; )
+ {
+ ptr = argv[index];
+ if (ptr[0] != '-')
+ {
+ printf("Invalid options format: %s\n", ptr);
+ exit(0);
+ }
+
+ switch (ptr[1])
+ {
+ case 'i':
+ nargs = arg_decimal(&argv[index], &value);
+ if (value < 0)
+ {
+ printf("Count must be non-negative: %d\n", value);
+ exit(1);
+ }
+
+ rmtchar->rmtchar_items = value;
+ index += nargs;
+ break;
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ case 't':
+ nargs = arg_string(&argv[index], &str);
+ rmtchar_devpath(rmtchar, str, true);
+ index += nargs;
+ break;
+#endif
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ case 'r':
+ nargs = arg_string(&argv[index], &str);
+ rmtchar_devpath(rmtchar, str, false);
+ index += nargs;
+ break;
+#endif
+ case 'h':
+ rmtchar_help(rmtchar);
+ exit(0);
+
+ default:
+ printf("Unsupported option: %s\n", ptr);
+ rmtchar_help(rmtchar);
+ exit(1);
+ }
+ }
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmtchar_main
+ ****************************************************************************/
+
+int main(int argc, FAR char *argv[])
+{
+ pthread_attr_t attr;
+ pthread_addr_t result;
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ pthread_t transmitter;
+#endif
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ pthread_t receiver;
+#endif
+#if defined(CONFIG_EXAMPLES_RMTCHAR_RX) && defined(CONFIG_EXAMPLES_RMTCHAR_TX)
+ struct sched_param param;
+#endif
+ int ret;
+
+ UNUSED(ret);
+
+ /* Check if we have initialized */
+
+ if (!g_rmtchar.initialized)
+ {
+ /* Set the default values */
+
+ g_rmtchar.rmtchar_items = CONFIG_EXAMPLES_RMTCHAR_ITEMS;
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ rmtchar_devpath(&g_rmtchar, CONFIG_EXAMPLES_RMTCHAR_TX_DEVPATH, true);
+#endif
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ rmtchar_devpath(&g_rmtchar, CONFIG_EXAMPLES_RMTCHAR_RX_DEVPATH, false);
+#endif
+
+ g_rmtchar.initialized = true;
+ }
+
+ /* Parse the command line */
+
+ parse_args(&g_rmtchar, argc, argv);
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ /* Start the receiver thread */
+
+ printf("rmtchar_main: Start receiver thread\n");
+ pthread_attr_init(&attr);
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ /* Bump the receiver priority from the default so that it will be above
+ * the priority of transmitter. This is important if a loopback test is
+ * being performed.
+ */
+
+ pthread_attr_getschedparam(&attr, ¶m);
+ param.sched_priority++;
+ pthread_attr_setschedparam(&attr, ¶m);
+#endif
+
+ /* Set the receiver stack size */
+
+ pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_RMTCHAR_RXSTACKSIZE);
+
+ /* Start the receiver */
+
+ ret = pthread_create(&receiver, &attr, rmtchar_receiver, &g_rmtchar);
+ if (ret != OK)
+ {
+ printf("rmtchar_main: ERROR: failed to Start receiver thread: %d\n",
+ ret);
+ return EXIT_FAILURE;
+ }
+
+ pthread_setname_np(receiver, "receiver");
+#endif
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ /* Start the transmitter thread */
+
+ printf("rmtchar_main: Start transmitter thread\n");
+ pthread_attr_init(&attr);
+
+ /* Set the transmitter stack size */
+
+ pthread_attr_setstacksize(&attr, CONFIG_EXAMPLES_RMTCHAR_TXSTACKSIZE);
+
+ /* Start the transmitter */
+
+ ret = pthread_create(&transmitter, &attr, rmtchar_transmitter, &g_rmtchar);
+ if (ret != OK)
+ {
+ printf("rmtchar_main: ERROR: failed to Start transmitter thread: %d\n",
+ ret);
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ printf("rmtchar_main: Waiting for the receiver thread\n");
+ pthread_join(receiver, &result);
+#endif
+ return EXIT_FAILURE;
+ }
+
+ pthread_setname_np(transmitter, "transmitter");
+#endif
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+ printf("rmtchar_main: Waiting for the transmitter thread\n");
+ ret = pthread_join(transmitter, &result);
+ if (ret != OK)
+ {
+ printf("rmtchar_main: ERROR: pthread_join failed: %d\n", ret);
+ }
+#endif
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+ printf("rmtchar_main: Waiting for the receiver thread\n");
+ ret = pthread_join(receiver, &result);
+ if (ret != OK)
+ {
+ printf("rmtchar_main: ERROR: pthread_join failed: %d\n", ret);
+ }
+#endif
+
+ return EXIT_SUCCESS;
+}
diff --git a/examples/rmtchar/rmtchar_receiver.c
b/examples/rmtchar/rmtchar_receiver.c
new file mode 100644
index 000000000..1f1e16a5f
--- /dev/null
+++ b/examples/rmtchar/rmtchar_receiver.c
@@ -0,0 +1,138 @@
+/****************************************************************************
+ * apps/examples/rmtchar/rmtchar_receiver.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <errno.h>
+#include <debug.h>
+#include <unistd.h>
+
+#include "rmtchar.h"
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_RX
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmtchar_receiver()
+ *
+ * Description:
+ * This is the entry point for the receiver thread.
+ *
+ ****************************************************************************/
+
+pthread_addr_t rmtchar_receiver(pthread_addr_t arg)
+{
+ FAR struct rmtchar_state_s *rmtchar = (FAR struct rmtchar_state_s *)arg;
+ struct rmt_item32_s buf[rmtchar->rmtchar_items];
+ int nread;
+ int fd;
+
+ /* Open the RMT character device */
+
+ fd = open(rmtchar->rxdevpath, O_RDONLY);
+ if (fd < 0)
+ {
+ int errcode = errno;
+ printf("rmtchar_receiver: ERROR: failed to open %s: %d\n",
+ rmtchar->rxdevpath, errcode);
+ pthread_exit(NULL);
+ }
+
+ /* Flush any output before reading */
+
+ fflush(stdout);
+
+ /* Read the buffer to the RMT character driver */
+
+ nread = read(fd, (char *)buf, rmtchar->rmtchar_items *
+ sizeof(struct rmt_item32_s));
+ if (nread < 0)
+ {
+ int errcode = errno;
+ if (errcode != EINTR)
+ {
+ printf("rmtchar_receiver: ERROR: read failed: %d\n",
+ errcode);
+ close(fd);
+ pthread_exit(NULL);
+ }
+ }
+ else
+ {
+ if (nread != (rmtchar->rmtchar_items * sizeof(struct rmt_item32_s)))
+ {
+ printf("rmtchar_receiver: ERROR: partial read: %d\n",
+ nread);
+ printf("rmtchar_receiver: Received buffer:\n");
+ print_items(buf, nread / sizeof(struct rmt_item32_s));
+ close(fd);
+ pthread_exit(NULL);
+ }
+ else
+ {
+ printf("rmtchar_receiver: Received buffer:\n");
+ print_items(buf, nread / sizeof(struct rmt_item32_s));
+ }
+ }
+
+ /* Make sure that the transmitter thread has a chance to run */
+
+ pthread_yield();
+
+ close(fd);
+ return NULL;
+}
+
+#endif /* CONFIG_EXAMPLES_RMTCHAR_RX */
diff --git a/examples/rmtchar/rmtchar_transmitter.c
b/examples/rmtchar/rmtchar_transmitter.c
new file mode 100644
index 000000000..e1b2c1a98
--- /dev/null
+++ b/examples/rmtchar/rmtchar_transmitter.c
@@ -0,0 +1,156 @@
+/****************************************************************************
+ * apps/examples/rmtchar/rmtchar_transmitter.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <errno.h>
+#include <debug.h>
+#include <unistd.h>
+
+#include <nuttx/audio/audio.h>
+
+#include "rmtchar.h"
+
+#ifdef CONFIG_EXAMPLES_RMTCHAR_TX
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: rmtchar_transmitter()
+ *
+ * Description:
+ * This is the entry point for the transmitter thread.
+ *
+ ****************************************************************************/
+
+pthread_addr_t rmtchar_transmitter(pthread_addr_t arg)
+{
+ FAR struct rmtchar_state_s *rmtchar = (FAR struct rmtchar_state_s *)arg;
+ struct rmt_item32_s buf[rmtchar->rmtchar_items];
+ int duration = 100;
+ int nwritten;
+ int fd;
+ int i;
+
+ /* Open the RMT character device */
+
+ fd = open(rmtchar->txdevpath, O_WRONLY);
+ if (fd < 0)
+ {
+ int errcode = errno;
+ printf("rmtchar_transmitter: ERROR: failed to open %s: %d\n",
+ rmtchar->txdevpath, errcode);
+ pthread_exit(NULL);
+ }
+
+ /* Fill the transmitter buffer with known items */
+
+ for (i = 0; i < rmtchar->rmtchar_items; i++)
+ {
+ buf[i].level0 = 1;
+ buf[i].duration0 = duration;
+ buf[i].level1 = 0;
+ buf[i].duration1 = duration;
+
+ duration += 10;
+ }
+
+ /* Flush any output before writing */
+
+ fflush(stdout);
+
+ /* Print the buffer to be sent */
+
+ print_items(buf, rmtchar->rmtchar_items);
+
+ /* Then send the buffer */
+
+ /* Write the buffer to the RMT character driver */
+
+ nwritten = write(fd, (char *)buf, rmtchar->rmtchar_items *
+ sizeof(struct rmt_item32_s));
+ if (nwritten < 0)
+ {
+ int errcode = errno;
+ if (errcode != EINTR)
+ {
+ printf("rmtchar_transmitter: ERROR: write failed: %d\n",
+ errcode);
+ close(fd);
+ pthread_exit(NULL);
+ }
+ }
+ else if (nwritten != (rmtchar->rmtchar_items *
+ sizeof(struct rmt_item32_s)))
+ {
+ printf("rmtchar_transmitter: ERROR: partial write: %d\n",
+ nwritten);
+ close(fd);
+ pthread_exit(NULL);
+ }
+ else
+ {
+ printf("rmtchar_transmitter: Send buffer with %d bytes\n",
+ rmtchar->rmtchar_items * sizeof(struct rmt_item32_s));
+ }
+
+ /* Make sure that the receiver thread has a chance to run */
+
+ pthread_yield();
+
+ close(fd);
+ return NULL;
+}
+
+#endif /* CONFIG_EXAMPLES_RMTCHAR_TX */
