Yoctopuce Yocto-Display, User Manual

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NSString * serial_or_name = [ NSString stringWithUTF8String : argv [ 1 ]] ;
// use serial or logical name
YModule * module = [ YModule FindModule : serial_or_name ] ;
if ( module.isOnline ) {
if ( argc > = 3 ) {
NSString * newname = [ NSString stringWithUTF8String : argv [ 2 ]] ;
if (![ YAPI CheckLogicalName : newname ]) {
NSLog ( @"Invalid name (%@) \n " , newname ) ;
usage ( argv [ 0 ]) ;
}
module.logicalName = newname;
[ module saveToFlash ] ;
}
NSLog ( @"Current name: %@ \n " , module.logicalName ) ;
} else {
NSLog ( @"%@ not connected (check identification and USB cable) \n " ,
serial_or_name ) ;
}
[ YAPI FreeAPI ] ;
}
return 0 ;
}
Warning: the number of write cycles of the nonvolatile memory of the module is limited. When this
limit is reached, nothing guaranties that the saving process is performed correctly. This limit, linked to
the technology employed by the module micro-processor, is located at about 100000 cycles. In short,
you can use the
saveToFlash
function only 100000 times in the life of the module. Make sure you
do not call this function within a loop.
Listing the modules
Obtaining the list of the connected modules is performed with the
yFirstModule()
function which
returns the first module found. Then, you only need to call the
nextModule()
function of this
object to find the following modules, and this as long as the returned value is not
NULL
. Below a
short example listing the connected modules.
#import <Foundation/Foundation.h>
#import "yocto_api.h"
int main ( int argc, const char * argv [])
{
NSError * error;
@autoreleasepool {
// Setup the API to use local USB devices
if([ YAPI RegisterHub : @"usb" :& error ] != YAPI_SUCCESS ) {
NSLog ( @"RegisterHub error: %@ \n " , [ error localizedDescription ]) ;
return 1 ;
}
NSLog ( @"Device list:
\n
" ) ;
YModule * module = [ YModule FirstModule ] ;
while ( module != nil ) {
NSLog ( @"%@ %@" , module.serialNumber, module.productName ) ;
module = [ module nextModule ] ;
}
[ YAPI FreeAPI ] ;
}
return 0 ;
}
12.3. Error handling
When you implement a program which must interact with USB modules, you cannot disregard error
handling. Inevitably, there will be a time when a user will have unplugged the device, either before
running the software, or even while the software is running. The Yoctopuce library is designed to help
12. Using Yocto-Display with Objective-C
www.yoctopuce.com 69