Texas Instruments MSP430 Student Guide

ABC’s of USB
C. Managing my App & Transferring Data

Main Loop USB Framework
while(1){
switch( USB_connectionState() )
{
case ST_USB_DISCONNECTED:
break;
case ST_ENUM_ACTIVE:
break;
case ST_ENUM_SUSPENDED:
break;
case ST_ENUM_IN_PROGRESS:
break;
case ST_USB_CONNECTED_NO_ENUM:
break;
case ST_NOENUM_SUSPENDED:
break;
case ST_ERROR:
break;
default:;
}
}
 Execution within main loop “forks”
depending on the state of USB,
creating alternate main loops
Thus, USB state becomes a central
part of managing software flow
 This framework excels when the
device behaves differently in each
state!
 For cases where system only cares
about one state, connectionState()
fxn could be called from IF{} stmt
 Most common non-RTOS solution –
it’s used in many of the USB
examples provided with the API
These three states are where
the application spends most
of its time
7 - 24 MSP430 Workshop - USB Devices

Texas Instruments MSP430 Specifications

General

Brand	Texas Instruments
Model	MSP430
Category	Microcontrollers
Language	English