The Simplest Network - Making Things Talk - page 41

Asynchronous Serial Communication

Figure 2-3
Types of serial communication.

Sender Receiver

Data goes this way

RX TX

Data goes this way

TX RX

Ground Ground

Synchronous Serial Communication

Master Slave

Chip Select CS

Master out,
slave in
Master in,
slave out
Clock

Data goes this way

MOSI

Data goes this way MISO

Clock signal goes this way

CLK

5V

Clock pulses

0V

Figure 2-4
Physical connections: USB,
RS-232 serial.

9 8 7 6

2 1

1 2 3 4

3 4

5 4 3 2 1

USB Type A USB Type B RS-232

1 - +5V
2 - Data-
3 - Data+
4 - Ground

2 - PC Receive
3 - PC Transmit
5 - PC Ground

USB Type Mini B

1 - +5V
2 - Data-
3 - Data+
4 - ID
5 - Ground

1 2 3 4 5