Datasheet

Jon Waddington
64
0 92 + 0 13 + 0 2 + 0 40 + 0 62 + 0 4 + 0 8 + 0 6 (4.4.2 - 3)
+ 0 68 + 0 01 + 01 + 0 01 + 0 02 + 0 73 + 0 3 = 0 4
Taking the lowest byte gives 0xFF, as expected, verifying that the information in the API
packet is correct.
4.5 RS232
Figure 4.5 shows the waveform for an RS232 signal transmitting the value 0x63 at
4800bps. The top waveform shows the signal as it is output from the Propeller, into the
MAX3232 IC and the bottom waveform shows the RS232 compatible signal as it outputs
the MAX3232 IC.
To calculate the theoretical bit period, the following equation was used
= = 208.33µ (4.5 - 1)
The measured bit period was equal to 210µs, a 0.8% error.
1
0
1
0
0
0
1
0
1
1
0V
3.3V
0V
+6V
-6V
Start LSB MSB Stop
Bit Bit
Figure 4.5. Waveform showing the RS232 Signal from the Propeller and MAX3232