Component: USB Slave (Comms: USB)

Author	Matrix Ltd.
Version	1.3
Category	Comms: USB

USB Slave component

Component to create and communicate using a generic USB communications profile. Has the ability to allow the device to be a slave to the PC. Compatible with simulation and USB enabled microcontroller devices (PIC/dsPIC).

Detailed description

No detailed description exists yet for this component

Examples

The PIC based ECIOs or MIAC are good targets for USB as they do not have any additional configuration setting that need to be setup to allow the firmware to run correctly. For other targets you will have to setup the configuration correctly for your hardware to allow the USB to run correctly.

Basic Embedded Example

Here is an example file which waits for incoming data and then when valid data is received it displays this as a binary value onto the PortB pins before echoing back the data. USB Slave Simple Receive

USB Drivers

The example requires a device driver to function correctly. The driver can be generated by selecting the USB Slave component on the System panel, Looking down the list of properties in the properties window, selecting the Generate Driver property and switching the setting to Yes. This will place the driver .inf file into the same directory as the Flowcode fcfx project file is located.

Here is a signed version of the USB Slave device driver using the default VID/PID properties. The .inf driver file generated by Flowcode also requires some associated files which are not auto generated, these files can also be downloaded here.

USB Slave Driver

The final driver files can be assembled by extracting the contents of the zip archive into a folder on your computer and adding the .inf file created by your Flowcode project. Running the correct executable for your PC type should then auto install the driver for you.

When the driver is installed correctly you will get your device showing up in the Windows device manager like this.

Basic Simulations Example

Here is an example file which is designed to run in simulation to communicate with the connected embedded device. The instance property will have to match the USB instance for the embedded device to allow the communications to work correctly. USB Slave Simulation The USB Slave instance is selected by selecting the USB slave component on the panel and setting the instance property.

When editing the USB Slave examples the slave service macro needs to match the setting in the USB Slave properties as shown below.

Slave Macro Setup

Slave Properties

Example console showing the data passed between the simulation and the embedded hardware.

The MIAC USB Slave and ECIO USB Slave Components are written based on the USB Slave component so these give a good example of what is possible using the component.

Downloadable macro reference

	SendString
Adds a string of bytes onto the end of the outgoing data buffer.
- STRING	Data
Data String To Send
- BYTE	Length
Max number of bytes to try and add to the outgoing buffer.
- BYTE	Return

	GetString
Retreives a string of data from the incoming data buffer starting from location 0 and incrementing up to the NumBytes parameter.
- BYTE	NumBytes
Specifies the maximum number of bytes to try and read.
- STRING	Return

	RunSlaveService
Stalls the microcontroller and waits for an incoming message from the USB, when a message is received the macro defined in the USB Slave properties is automatically run. While the macro is running you can choose to send data back to the PC if you wish.
- VOID	Return

	SendByte
Adds the byte onto the end of the outgoing data buffer.
- BYTE	Data
Data byte to transmit to the host
- BYTE	Return

	SendByteArray
Adds an array of bytes onto the end of the outgoing data buffer.
[[File:]] -	Data
Data Bytes To Send
- BYTE	Length
Max number of bytes to try and add to the outgoing buffer.
- BYTE	Return

	CheckRx
Called to check if there is any incoming data waiting to be received. Returns the number of incoming data bytes. Only needed when not running the slave service.
- BYTE	Return

	GetByte
Retreives the byte at location Idx from the incoming data buffer.
- BYTE	Idx
Specifies the location in the incoming buffer
- BYTE	Return

	StopSlaveService
Allows the microcontroller to leave the stalled slave mode and resume its normal independant functionality. Must be called from within the slave service routine to work correctly.
- VOID	Return

	Initialise
Starts up the USB communications and attempts to enumerate. Returns 0 for a successful startup or 255 for a enumeration timeout.
- BYTE	Return

Property reference

	Properties
	Vendor ID
USB VID
	Product ID
USB PID
	Device Name
USB Device Name
	Manufacturer
USB Manufacturer
	Major Version
USB Major Version Number
	Minor Version
USB Minor Version Number
	Enumeration Timeout
Specifies if the enumeration (Initialise function) can timeout if taking too long.
	Country Code
Country code used by some regional based USB devices
	Maximum Current (mA)
Maximum amount of current the USB host will provide before shutting down the USB channel.
	Slave Macro
Flowcode macro to call while the slave service is enabled
	Macro Parameters
Defines the parameters for the slave service macro allowing data from the host to be automatically passed into the macro.
	Driver Directory
Directory to save the generated device driver .inf file
	Driver Filename
Filename assigned to the USB device driver .inf file when generated.
	Generate Driver
Generates a driver file when set to Yes, Automatically jumps back to No when complete.
	Connections
	Simulations
	Instance
Hardware instance to communicate with any connected USB slave devices.
	Timeout (ms)
Simulation host to slave communications timeout in milliseconds
	Label
Text displayed on the I/O flasher comms component.