To be able to debug a reader driver you may need to start pcscd by hand instead of automatically when the reader is connected.
To do that, edit the file /System/Library/LaunchDaemons/com.apple.securityd.plist
Change the file from something like:
<key>ProgramArguments</key>
<array>
<string>/usr/sbin/securityd</string>
<string>-i</string>
</array>
to something like:
<key>ProgramArguments</key>
<array>
<string>/usr/sbin/securityd</string>
<string>-i</string>
<string>-s</string>
<string>off</string>
</array>
Reboot
Source: https://lists.apple.com/archives/apple-cdsa/2007/Nov/msg00009.html