blob: c6486da69817f5c00f60867c909114b24ff247e7 [file] [log] [blame]
// Copyright 2021 The Pigweed Authors
// 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
// 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 "pw_sys_io/sys_io.h"
#include <cinttypes>
#include <string_view>
#include "board.h"
#include "fsl_common.h"
#include "fsl_debug_console.h"
#include "pw_status/status.h"
#include "pw_status/status_with_size.h"
extern "C" void pw_sys_io_mcuxpresso_Init(void) { BOARD_InitDebugConsole(); }
namespace pw::sys_io {
// Wait for a byte to read on USART0. This blocks until a byte is read. This is
// extremely inefficient as it requires the target to burn CPU cycles polling to
// see if a byte is ready yet.
Status ReadByte(std::byte* dest) {
*dest = static_cast<std::byte>(DbgConsole_Getchar());
return OkStatus();
// Read a byte from USART0 if one is available.
Status TryReadByte(std::byte* dest) {
char ch = 0;
status_t status = DbgConsole_TryGetchar(&ch);
if (status != kStatus_Success) {
return Status::Unavailable();
*dest = static_cast<std::byte>(ch);
return OkStatus();
Status TryReadByte(std::byte* /*dest*/) { return Status::Unimplemented(); }
// Send a byte over USART0. Since this blocks on every byte, it's rather
// inefficient. At the default baud rate of 115200, one byte blocks the CPU for
// ~87 micro seconds. This means it takes only 10 bytes to block the CPU for
// 1ms!
Status WriteByte(std::byte b) {
int ch = static_cast<int>(b);
int len = DbgConsole_Putchar(ch);
return len == 1 ? OkStatus() : Status::Unknown();
// Writes a string using pw::sys_io, and add newline characters at the end.
StatusWithSize WriteLine(const std::string_view& s) {
size_t chars_written = 0;
StatusWithSize result = WriteBytes(as_bytes(span(s)));
if (!result.ok()) {
return result;
chars_written += result.size();
// Write trailing newline.
result = WriteBytes(as_bytes(span("\r\n", 2)));
chars_written += result.size();
return StatusWithSize(result.status(), chars_written);
} // namespace pw::sys_io