Get a method of setting custom baud rates building.
diff --git a/bbb_cape/src/bbb/uart_receiver.cc b/bbb_cape/src/bbb/uart_receiver.cc
index 1150c55..981e40b 100644
--- a/bbb_cape/src/bbb/uart_receiver.cc
+++ b/bbb_cape/src/bbb/uart_receiver.cc
@@ -1,8 +1,10 @@
+#include <fcntl.h>
+#include <linux/serial.h>
+#include <termio.h>
+#include <unistd.h>
+
#include <cmath>
#include <cstring>
-#include <fcntl.h>
-#include <termios.h>
-#include <unistd.h>
#include "aos/common/logging/logging_impl.h"
#include "bbb_cape/src/cape/cows.h"
@@ -13,9 +15,12 @@
// NOTE: In order for this to work, you MUST HAVE "capemgr.enable_partno=BB_UART1"
// in your BBB's /media/BEAGLEBONE/uEnv.txt file!
+// Implementation for setting custom serial baud rates based on this code:
+// <http://jim.sh/ftx/files/linux-custom-baudrate.c>
+
namespace bbb {
-UartReceiver::UartReceiver(speed_t baud_rate, size_t packet_size) :
+UartReceiver::UartReceiver(uint32_t baud_rate, size_t packet_size) :
baud_rate_(baud_rate), packet_size_(packet_size) {
//packet_size_ should be a multiple of four.
int toadd = packet_size_ % 4;
@@ -33,28 +38,53 @@
}
int UartReceiver::SetUp() {
- termios cape;
+ termios options;
+ serial_struct serinfo;
if ((fd_ = open("/dev/ttyO1", O_RDWR | O_NOCTTY)) < 0) {
LOG(FATAL, "Open() failed with error %d.\
(Did you read my note in uart_receiver.cc?)\n", fd_);
}
- if (int ret = tcgetattr(fd_, &cape)) {
- LOG(ERROR, "Tcgetattr() failed with error %d.\n", ret);
+
+ // Must implement an ugly custom divisor.
+ serinfo.reserved_char[0] = 0;
+ if (ioctl(fd_, TIOCGSERIAL, &serinfo) < 0)
return -1;
- }
- if (int ret = cfsetispeed(&cape, baud_rate_) < 0) {
- LOG(ERROR, "Cfsetispeed() failed with error %d.\n", ret);
+ serinfo.flags &= ~ASYNC_SPD_MASK;
+ serinfo.flags |= ASYNC_SPD_CUST;
+ serinfo.custom_divisor = (serinfo.baud_base + (baud_rate_ / 2)) / baud_rate_;
+ if (serinfo.custom_divisor < 1)
+ serinfo.custom_divisor = 1;
+ if (ioctl(fd_, TIOCSSERIAL, &serinfo) < 0)
+ LOG(ERROR, "First ioctl failed.\n");
return -1;
+ if (ioctl(fd_, TIOCGSERIAL, &serinfo) < 0)
+ LOG(ERROR, "Second ioctl failed.\n");
+ return -1;
+ if (serinfo.custom_divisor * static_cast<int>(baud_rate_)
+ != serinfo.baud_base) {
+ LOG(WARNING, "actual baudrate is %d / %d = %f",
+ serinfo.baud_base, serinfo.custom_divisor,
+ (float)serinfo.baud_base / serinfo.custom_divisor);
}
- cape.c_iflag = 0;
- cape.c_oflag = 0;
- cape.c_lflag = 0;
- cape.c_cc[VMIN] = 0;
- cape.c_cc[VTIME] = 0;
-
- tcsetattr(fd_, TCSANOW, &cape);
+ fcntl(fd_, F_SETFL, 0);
+ tcgetattr(fd_, &options);
+ cfsetispeed(&options, B38400);
+ cfsetospeed(&options, B38400);
+ cfmakeraw(&options);
+ options.c_cflag |= (CLOCAL | CREAD);
+ options.c_cflag &= ~CRTSCTS;
+ options.c_iflag = 0;
+ options.c_oflag = 0;
+ options.c_lflag = 0;
+ // We know the minimum size for packets.
+ // No use in having it do excessive syscalls.
+ options.c_cc[VMIN] = packet_size_;
+ options.c_cc[VTIME] = 0;
+ if (tcsetattr(fd_, TCSANOW, &options) != 0)
+ LOG(ERROR, "Tcsetattr failed.\n");
+ return -1;
return 0;
}