Pin-Io; Data Rates On Rs-232 Api; Plain Serial Interface; Figure 12: Test Case For Measuring Java Midlet Performance And Handling Pin-Io - Siemens TC65 JAVA User Manual

TC65 JAVA User's Guide
Strictly confidential / Draft
5.8.2

Pin-IO

The pin IO test was defined to find out how fast a Java MIDlet can process URCs caused by
Pin IO and react on these URCs.
The URCs are generated by feeding an input pin with an external frequency. As soon as the
Java MIDlet gets informed about the URC, it tries to regenerate the feeding frequency by
toggling another output pin.
external frequency
generated frequency

Figure 12: Test case for measuring Java MIDlet performance and handling pin-IO

The results of this test show that the delay from changing the state on the pin to processing
the URC in the MIDlet is at least 20 TDMA frames, but depends mainly on the amount of
garbage to collect and number of thread to serve by the virtual machine. So Pin IO is not
suitable to generate or detect frequencies.
5.8.3

Data Rates on RS-232 API

For details about software platform and interfaces refer to Chapter 4, "Software Platform".
This section summarises limitations and preconditions for performance when using the
interface CommConnection from package com.siemens.mp.io (refer to [6]).
The data rate on RS232 depends on the size of the buffer used for reading from and writing
to the serial interface. It is recommended to use for reading from serial interface the method
read (byte[ ] b). The recommended buffer size is 2kbyte.
To reach errorfree data transmission the flowcontrol on CommConnection has to be switched
on: <autorts> and <autocts>, the same for connected device.
Below, different use cases are listed to give an idea of reachable data rates. All applications
for measurements are working with only one thread, no more activities than those described
were done in parallel.
5.8.3.1

Plain Serial Interface

Scenario: A device is connected to ASC0 (refer to 4.2.4). The Java application has to handle
data input and output streams.
A simple Java application (only one thread) which is looping incoming data directly to output
reaches data rates up to 140kbit/s. Test conditions: hardware flow control enabled (<autorts>
and <autocts>) and baud rate on ASC0 set to 230kbit/s.
TC65 JAVA User's Guide_V01
input pin
poll input pin send URC
set output pin
output pin
Page 30 of 69
s
Test MIDlet
ATCommandListener.
ATEvent()
ATCommand.
send(...)
11.03.2005