User Guide

Table Of Contents
Serial and USB Interfaces
Functionality of the Embedded Modules 29
Serial and USB Interfaces
The M6e-TC module can communicate to a host processor via the TTL logic level RS-232
serial protocol or via Universal Serial Bus (USB) protocol, both accessed on the 14-pin
M6e-TC Digital Connectors.
The module does not need to be software configured to operate on one or the other
interface, just send data over the interface to use it. However, the following considerations
should be made when using one or both interfaces:
Once a command is initiated on one interface, the entire synchronous operation (full
command and response) must be completed on that interface. Upon completion of
an operation a new command can be sent on either interface.
If both interfaces are to be used the user is responsible for maintaining order of
execution. If commands are sent on both interfaces simultaneously execution order
cannot be guaranteed.
When setting the baud rate via Set Baud Rate (06h) this changes the communication
speed on the RS232 Interface only, whether set using the RS232 interface or USB.
The USB speed is not changed. USB communication speed is dictated by the USB
protocol and has a maximum bitrate of 12Mbps.
When configuring Power Modes, using Maximum Saving Mode (0x03) will shut off the
USB interface. If
Set Power Mode (98h) is called using the USB interface and mode
0x03 is specified the module will instead be set to Medium Saving Mode (0x02). In
order to set the module to mode 0x03 the command must be called using the RS232
interface.
Power consumption will increase when the USB interface is connected.
A level converter is necessary to interface to other devices that use standard 12V RS-
232.
Only three pins are required for RS232 communication (TX, RX, and GND). Hardware
handshaking is not supported.
The interfaces use an interrupt-driven FIFO that empties into a circular buffer.
The developer is responsible for ensuring that the host processor’s RS232 receiver
has the capability to receive up to 256 bytes of data at a time without overflowing.
Installing the USB Driver
Windows
When connecting to the M6e-TC through the USB interface from a Windows PC a few
installation steps are required for Windows to recognize the M6e-TC and properly