I'm working on a university project that involves a lot of programming in C, especially with Portaudio & ALSA. At the moment i'm trying to make a callback function to pass audio through, standard input/output job. I was wondering if anybody could tell me how to print the floats from my inputBuffer to display in real time in the terminal? Here is the internal structure of my callback function so far.
Thanks very much for your help in advance!
#define SAMPLE_RATE (44100)
#define PA_SAMPLE_TYPE paFloat32
#define FRAMES_PER_BUFFER (64)
typedef float SAMPLE;
static int audio_callback( const void *inputBuffer, void *outputBuffer,
unsigned long framesPerBuffer,
const PaStreamCallbackTimeInfo* timeInfo,
PaStreamCallbackFlags statusFlags,
void *userData )
{
SAMPLE *out = (SAMPLE*)outputBuffer;
const SAMPLE *in = (const SAMPLE*)inputBuffer;
unsigned int i;
(void) timeInfo; /* Prevent unused variable warnings. */
(void) statusFlags;
(void) userData;
if( inputBuffer == NULL )
{
for( i=0; i<framesPerBuffer; i++ )
{
*out++ = *in++; /* left - clean */
*out++ = *in++; /* right - clean */
}
}
return paContinue;
}
Related
I have small problem with adding and reading values.
Define variables
#define ADC_BIT_MASK 0x0FFF
static TaskHandle_t remoteControlTaskHandle = NULL;
typedef enum
{
...
rcEvent_FreshADC = 0x80000000,
...
}
Code for notify task. adc12bitVal_pedal value is for example 100 and adc12bitVal_lr value for example 1000. I am shifting adc12bitVal_lr to the left that I can pass params ...
static void remoteControl_FreshADC(uint16_t adc12bitVal_pedal, uint16_t adc12bitVal_lr)
{
if(remoteControlTaskHandle != NULL)
{
xTaskNotify(remoteControlTaskHandle,
(rcEvent_FreshADC | (adc12bitVal_pedal & ADC_BIT_MASK) | (adc12bitVal_lr & ADC_BIT_MASK)<<12),
eSetValueWithOverwrite);
}
}
and then remoteControlHandleEvent which handle an event. Here I have problem with adcVal_lr which should be 1000 but is for example 52123. I need to shift 12 to the left that I get correct value. Or this is wrong?
returnCode_t remoteControlHandleEvent(remoteControlEvent_t event)
{
if(event & rcEvent_motorControlACK)
{
uint8_t ackNum = (uint8_t) ( ((event >> MOTOR_CONTROL_ACK_BIT_POS) & MOTOR_CONTROL_ACK_BIT_MASK));
printf("CONF: %u\n", (unsigned int)ackNum);
}
if(event & rcEvent_FreshADC)
{
...
// Value is 100
uint16_t adcVal_pedal = (uint16_t)(event & ADC_BIT_MASK);
// DOESN'T WORK VALUE IS 52123 instead of 1000
uint16_t adcVal_lr = (uint16_t)((event & ADC_BIT_MASK)<<12);
...
}
}
I don't understand and know why wrong value for
uint16_t adcVal_lr = (uint16_t)((event & ADC_BIT_MASK)<<12);
Thnak you for all comments and help.
You are shifting left (up) twice. To extract a value that you shifted left you need to shift right (down). You also apply the mask before shifting, when it should be after.
uint16_t adcVal_lr = (uint16_t)((event >> 12) & ADC_BIT_MASK);
I want to have my Zedboard return a numeric value using the Xilinx lwIP example as a base but no matter what I do I can't figure out what stores the data received or transmitted.
I have found the void type payload but I don't know what to do with it.
Snapshot of one instance of payload and a list of lwIP files
Below is the closest function to my goal:
err_t recv_callback(void *arg, struct tcp_pcb *tpcb,
struct pbuf *p, err_t err){
/* do not read the packet if we are not in ESTABLISHED state */
if (!p) {
tcp_close(tpcb);
tcp_recv(tpcb, NULL);
return ERR_OK;
}
/* indicate that the packet has been received */
tcp_recved(tpcb, p->len);
/* echo back the payload */
/* in this case, we assume that the payload is < TCP_SND_BUF */
if (tcp_sndbuf(tpcb) > p->len) {
err = tcp_write(tpcb, p->payload, p->len, 1);
//I need to change p->paylod but IDK where it is given a value.
} else
xil_printf("no space in tcp_sndbuf\n\r");
/* free the received pbuf */
pbuf_free(p);
return ERR_OK;
}
Any guidance is appreciated.
Thanks,
Turtlemii
-I cheated and just made sure that the function has access to Global_tpcb from echo.c
-tcp_write() reads in an address and displays each char it seems.
void Print_Code()
{
/* Prepare for TRANSMISSION */
char header[] = "\rSwitch: 1 2 3 4 5 6 7 8\n\r"; //header text
char data_t[] = " \n\r\r"; //area for storing the
data
unsigned char mask = 10000000; //mask to decode switches
swc_value = XGpio_DiscreteRead(&SWCInst, 1); //Save switch values
/* Write switch values to the LEDs for visual. */
XGpio_DiscreteWrite(&LEDInst, LED_CHANNEL, swc_value);
for (int i =0; i<=7; i++) //load data_t with switch values (0/1)
{
data_t[8+2*i] = '0' + ((swc_value & mask)/mask); //convert one bit to 0/1
mask = mask >> 1;//move to next bit
}
int len_header = *(&header + 1) - header; //find the length of the
header string
int len_data = *(&data_t + 1) - data_t; //find the length of the data string
tcp_write(Global_tpcb, &header, len_header, 1); //print the header
tcp_write(Global_tpcb, &data_t, len_data, 1); //print the data
}
So I'm working on a Gtk/X11/Linux app that does screen capture to .gif and one of the methods of stopping the capture is a key press (Esc, Space or End). You can also use a timeout. However to implement the key press to end capture I have to be able to grab the key such that I can get an event even though my window doesn't have focus (it's actually invisible during capture). I believe XGrabKey is the right X11 function for this task:
Window w = Gtk::gdk_x11_drawable_get_xid(Gtk::gtk_widget_get_window(Handle()));
KeyCode kc = XKeysymToKeycode(Gtk::gdk_display, HotKeyCode);
int r = XGrabKey( Gtk::gdk_display,
kc,
0 /* modifiers */,
w /* grab_window */,
TRUE /* owner_events */,
GrabModeAsync /* pointer_mode */,
GrabModeAsync /* keyboard_mode */);
printf("XGrabKey(%p, 0x%x/%x)=%i\n", w, HotKeyCode, kc, r);
Where 'HotKeyCode' is say XK_Escape or something e.g.:
XGrabKey(0x3e00003, 0xff1b/9)=1
XGrabKey is returning '1' or BadRequest. What am I doing wrong here?
FYI the actual Xorg Xserver code in question appears to be here.
Edit: The latest incarnation of the code is:
int x_err_callback(Display *d, XErrorEvent *e)
{
char msg[256];
XGetErrorText(d, e->error_code, msg, sizeof(msg));
printf("X11Error %d (%s): request %d.%d\n",
e->error_code, msg, e->request_code,
e->minor_code);
return 0;
}
Gtk::GdkFilterReturn key_filter(Gtk::GdkXEvent *gdk_xevent,
Gtk::GdkEvent *event,
Gtk::gpointer data)
{
XKeyEvent *xevent = gdk_xevent;
if (xevent->type == KeyPress)
{
int key = ((XKeyEvent *)gdk_xevent)->keycode;
int keysym = XKeycodeToKeysym(Gtk::gdk_display, key, 0);
printf("caught keysym %i\n", keysym);
switch (keysym)
{
case 1: // your_keysym
// your key handler code
break;
}
}
return Gtk::GDK_FILTER_CONTINUE;
}
Gtk::GdkWindow *Root = Gtk::gdk_get_default_root_window();
KeyCode kc = XKeysymToKeycode(Gtk::gdk_display, HotKeyCode);
XSetErrorHandler(x_err_callback);
int r = XGrabKey( Gtk::gdk_display,
kc,
AnyModifier /* modifiers */,
GDK_WINDOW_XWINDOW(Root) /* grab_window */,
TRUE /* owner_events */,
GrabModeAsync /* pointer_mode */,
GrabModeSync /* keyboard_mode */);
Gtk::gdk_window_set_events(Root,
(Gtk::GdkEventMask)
(Gtk::GDK_KEY_PRESS_MASK |
Gtk::GDK_KEY_RELEASE_MASK));
Gtk::gdk_window_add_filter(NULL, key_filter, this);
AnyModifier actually results in an error. '0' doesn't. I know about the NumLock issue...
A return value of 1 does not mean that a BadRequest error occured. Xlib handles errors via an error handler, and the function will always return 1, if it returns at all.
Your code does not work because you have to do the XGrabKey on the root window (GetDefaultRootWindow(Gtk::gdk_display)). Here's a pure Xlib demo:
#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <stdio.h>
int main() {
Display *d = XOpenDisplay(0);
Window root = DefaultRootWindow(d);
int keycode = XKeysymToKeycode(d, XK_BackSpace);
int rv = XGrabKey(d, keycode, AnyModifier, root, 1, GrabModeAsync, GrabModeAsync);
printf("XGrabKey returned %d\n", rv);
XEvent evt;
while(1) {
XNextEvent(d, &evt);
printf("Got event %d\n", evt.type);
}
}
To then capture the X11 events from GTK use gdk_window_add_filter on a NULL or on the root window and a GdkFilterFunc that processes the events associated with your global hotkey:
#include <X11/Xlib.h>
#include <X11/keysym.h>
#include <gtk/gtk.h>
#include <gdk/gdkx.h>
#include <stdio.h>
GdkFilterReturn filter(GdkXEvent *xevent, GdkEvent *event, gpointer data) {
XKeyEvent *ev = (XKeyEvent *)xevent;
if(ev->type == 2) {
printf("Backspace hit.\n");
}
return GDK_FILTER_CONTINUE;
}
int main(int argc, char *argv[]) {
gtk_init(&argc, &argv);
GdkScreen *scr = gdk_screen_get_default();
GdkWindow *groot = gdk_screen_get_root_window(scr);
gdk_window_set_events(groot, GDK_KEY_PRESS_MASK);
gdk_window_add_filter(groot, filter, NULL);
Display *d = gdk_x11_get_default_xdisplay();
Window root = GDK_WINDOW_XID(groot);
int keycode = XKeysymToKeycode(d, XK_BackSpace);
XGrabKey(d, keycode, AnyModifier, root, 1, GrabModeAsync, GrabModeAsync);
gtk_main();
}
As a side note, a modifier mask of 0 means that no modifiers must be enabled, even those that would not modify the meaning of a key. A grab on the letter "A" with a 0 modifier would not match NumLock + A. That's why I used AnyModifer.
I have a sketch to take information (Lat, Long) from an EM-406a GPS receiver and write the information to an SD card on an Arduino shield.
The program is as follows:
#include <TinyGPS++.h>
#include <SoftwareSerial.h>
#include <SD.h>
TinyGPSPlus gps;
SoftwareSerial ss(4, 3); //pins for the GPS
Sd2Card card;
SdVolume volume;
SdFile root;
SdFile file;
void setup()
{
Serial.begin(115200); //for the serial output
ss.begin(4800); //start ss at 4800 baud
Serial.println("gpsLogger by Aaron McRuer");
Serial.println("based on code by Mikal Hart");
Serial.println();
//initialize the SD card
if(!card.init(SPI_FULL_SPEED, 9))
{
Serial.println("card.init failed");
}
//initialize a FAT volume
if(!volume.init(&card)){
Serial.println("volume.init failed");
}
//open the root directory
if(!root.openRoot(&volume)){
Serial.println("openRoot failed");
}
//create new file
char name[] = "WRITE00.TXT";
for (uint8_t i = 0; i < 100; i++){
name[5] = i/10 + '0';
name[6] = i%10 + '0';
if(file.open(&root, name, O_CREAT | O_EXCL | O_WRITE)){
break;
}
}
if(!file.isOpen())
{
Serial.println("file.create");
}
file.print("Ready...\n");
}
void loop()
{
bool newData = false;
//For one second we parse GPS data and report some key values
for (unsigned long start = millis(); millis() - start < 1000;)
{
while (ss.available())
{
char c = ss.read();
//Serial.write(c); //uncomment this line if you want to see the GPS data flowing
if(gps.encode(c)) //did a new valid sentence come in?
newData = true;
}
}
if(newData)
{
file.write(gps.location.lat());
file.write("\n");
file.write(gps.location.lng());
file.write("\n");
}
file.close();
}
When I open up the file on the SD card when the program is finished executing, I get a message that it has an encoding error.
I'm currently inside (and unable to get a GPS signal, thus the 0), but the encoding problem needs to be tackled, and there should be as many lines as there are seconds that the device has been on. There's only that one. What do I need to do to make things work correctly here?
Closing the file in the loop, and never reopening it, is the reason there's only one set of data in your file.
Are you sure gps.location.lat() and gps.location.lng() return strings, not an integer or float? That would explain the binary data and the "encoding error" you see.
EDIT: I have created a ticket for this which has data on an alternative to this way of doing things.
I have updated the code in an attempt to use MY_CXT's callback as gcxt was not storing across threads. However this segfaults at ENTER.
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#ifndef aTHX_
#define aTHX_
#endif
#ifdef USE_THREADS
#define HAVE_TLS_CONTEXT
#endif
/* For windows */
#ifndef SDL_PERL_DEFINES_H
#define SDL_PERL_DEFINES_H
#ifdef HAVE_TLS_CONTEXT
PerlInterpreter *parent_perl = NULL;
extern PerlInterpreter *parent_perl;
#define GET_TLS_CONTEXT parent_perl = PERL_GET_CONTEXT;
#define ENTER_TLS_CONTEXT \
PerlInterpreter *current_perl = PERL_GET_CONTEXT; \
PERL_SET_CONTEXT(parent_perl); { \
PerlInterpreter *my_perl = parent_perl;
#define LEAVE_TLS_CONTEXT \
} PERL_SET_CONTEXT(current_perl);
#else
#define GET_TLS_CONTEXT /* TLS context not enabled */
#define ENTER_TLS_CONTEXT /* TLS context not enabled */
#define LEAVE_TLS_CONTEXT /* TLS context not enabled */
#endif
#endif
#include <SDL.h>
#define MY_CXT_KEY "SDL::Time::_guts" XS_VERSION
typedef struct {
void* data;
SV* callback;
Uint32 retval;
} my_cxt_t;
static my_cxt_t gcxt;
START_MY_CXT
static Uint32 add_timer_cb ( Uint32 interval, void* param )
{
ENTER_TLS_CONTEXT
dMY_CXT;
dSP;
int back;
ENTER; //SEGFAULTS RIGHT HERE!
SAVETMPS;
PUSHMARK(SP);
XPUSHs(sv_2mortal(newSViv(interval)));
PUTBACK;
if (0 != (back = call_sv(MY_CXT.callback,G_SCALAR))) {
SPAGAIN;
if (back != 1 ) Perl_croak (aTHX_ "Timer Callback failed!");
MY_CXT.retval = POPi;
} else {
Perl_croak(aTHX_ "Timer Callback failed!");
}
FREETMPS;
LEAVE;
LEAVE_TLS_CONTEXT
dMY_CXT;
return MY_CXT.retval;
}
MODULE = SDL::Time PACKAGE = SDL::Time PREFIX = time_
BOOT:
{
MY_CXT_INIT;
}
SDL_TimerID
time_add_timer ( interval, cmd )
Uint32 interval
void *cmd
PREINIT:
dMY_CXT;
CODE:
MY_CXT.callback=cmd;
gcxt = MY_CXT;
RETVAL = SDL_AddTimer(interval,add_timer_cb,(void *)cmd);
OUTPUT:
RETVAL
void
CLONE(...)
CODE:
MY_CXT_CLONE;
This segfaults as soon as I go into ENTER for the callback.
use SDL;
use SDL::Time;
SDL::init(SDL_INIT_TIMER);
my $time = 0;
SDL::Timer::add_timer(100, sub { $time++; return $_[0]} );
sleep(10);
print "Never Prints";
Output is
$
it should be
$ Never Prints
Quick comments:
Do not use Perl structs (SV, AV, HV, ...) outside of the context of a Perl interpreter object. I.e. do not use it as C-level static data. It will blow up in a threading context. Trust me, I've been there.
Check out the "Safely Storing Static Data in XS" section in the perlxs manpage.
Some of that stuff you're doing looks rather non-public from the point of view of the perlapi. I'm not quite certain, though.
$time needs to be a shared variable - otherwise perl works with separate copies of the variable.
My preferred way of handling this is storing the data in the PL_modglobal hash. It's automatically tied to the current interpreter.
We have found a solution to this using Perl interpreter threads and threads::shared. Please see these
Time.xs
Also here is an example of a script using this code.
TestTimer.pl