Cannot find peripheral when scanning for specific service CBUUID - ios

Question

When I use:
CBUUID * uuid = [CBUUID UUIDWithString:#"1800"]; // GAP
DEBUG_LOG(#"CBUUID: %#",uuid); // CBUUID: Generic Access Profile
_centralMan = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
[_centralMan scanForPeripheralsWithServices:[NSArray arrayWithObject:uuid]
options:nil];
I cannot find my peripheral, but when I use:
_centralMan = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
[_centralMan scanForPeripheralsWithServices:nil
options:nil];
…it shows up immediately.
When I connect, I am able to discover/read/write to all the services I am expecting. My understanding is that GAP makes this possible. I have also tried CBUUID's for other services that I know are running (specifically "1804", TX power service), to no avail; the scan never discovers anything.
Even though the services are running (I can communicate w/ them upon connecting), when I scan passing the service UUID array as nil and this delegate method is called...
-(void) centralManager:(CBCentralManager *)central
didDiscoverPeripheral:(CBPeripheral *)peripheral
advertisementData:(NSDictionary *)advertisementData
RSSI:(NSNumber *)RSSI {
DEBUG_LOG(#"Found peripheral w/ UUID: %# RSSI: %# \n AdvData: %#",peripheral.UUID,RSSI,advertisementData);
DEBUG_LOG(#"Services found: %d",peripheral.services.count);
for (CBService * service in peripheral.services) {
DEBUG_LOG(#"Found service: %# w/ UUID %#",service, service.UUID);
}
}
…it always reports "Services found: 0". Should I expect the services array to be populated w/ services found during the scan? (I assume this is at least partially possible, based on scanForPeripheralsWithServices:[NSArray arrayWithObject:uuid]
options:nil.)
Could this be a problem w/ my peripheral's service advertisements? Am I using the API incorrectly? Any guidance is much appreciated! :-)
PS: I'm pretty green w/ Bluetooth.
PPS: I control the source to the peripheral (it's a CC2540DK). So I'd be as likely to believe the problem is there as it is here.

Answer 1

Turns out our peripheral code was not advertising the UUIDs a la this Bluetooth spec.
As soon as we dropped them into the advertising packet, iOS picked them up no sweat.