Component: I2C Multiplexer (TCA9548A) (Comms: System)

Author	MatrixTSL
Version	1.0
Category	Comms: System

I2C Multiplexer (TCA9548A) component

An I2C multiplexing IC allowing up to 8 different I2C busses to be connected to a single I2C channel on your target microcontroller.

Detailed description

No detailed description exists yet for this component

Examples

Here we have a simple example showing how to use the multiplexer to connect multiple of the same I2C sensor IC to the microcontroller.

The multiplexer IC is connected directly to the microcontroller I2C pins and up to 8 temp/humidity sensors are connected to the CH0-CH7 I2C pins of the multiplexer.

I2C Multiplex Example

Downloadable macro reference

	SelectChannel
Selects a single output channel to multiplex the I2C output to (0-7).
- BYTE	Channel
Range: 0-7
- VOID	Return

	SetChannelMask
Allows a user determined number of channels to be connected to the I2C bus.
- BYTE	Mask
Range: 0-255 / Bit0=CH0 EN / Bit1 = CH1 EN etc
- VOID	Return

	Initialise
Startup the I2C bus ready for communications.
- VOID	Return

	Transaction_Read
Attempt to read Length number of bytes from the I2C slave to the given Buffer. Ensure that the Buffer is large enough. Returns number of bytes read, caller should check that this matches requested Length
- BYTE	Buffer
Buffer to store the incoming byte data
- UINT	Length
Number of bytes to read
- UINT	Return

	Start
Outputs a start condition onto the I²C bus.
- VOID	Return

	Transaction_Initialise
Initialise the I2C interface to communicate with a Slave device at Address Returns 0 on fail, 1 on success
- BYTE	Address
7-bit I2C Address without the shift for the R/W bit
- BYTE	Return

	Initialise
Enables the I²C hardware and performs some initialization. Should be called at the start of the program or at least before any of the other I²C functions are called.
- VOID	Return

	GetInt
Gets an integer from the LUT
- ULONG	Index
- ULONG	Return

	SetFloatBits
Sets the size of a float LUT entry
- BYTE	Bits
- VOID	Return

	AddInt
Int to add to the int array
- ULONG	Value
Int to add to the int array
- VOID	Return

	AddFloat
Add a float to the floating point LUT
[[File:]] -	Value
Floating point values
- VOID	Return

	Initialise
Sets up the GSM module. Returns 0 for OK, 255 for no reply and 254 for command fail.
- BYTE	Return

	SampleAccel
Samples the accelerometer 0 = no new data, 1 = new data available
- BYTE	Return

	Left
Rotates the robot left - waits for the angle to be traversed before returning
- UINT	Angle
Angle to turn in degrees
- VOID	Return

	ReadIR
Reads an IR sensor 0=Left, 1=FrontLeft, 2=Front, 3=FrontRight, 4=Right, 5=RearRight, 6=Rear, 7=RearLeft
- BYTE	index
0=Left, 1=FrontLeft, 2=Front, 3=FrontRight, 4=Right, 5=RearRight, 6=Rear, 7=RearLeft
- UINT	Return

	LCDDrawPixel
Allows a single pixel on the LCD to be set or cleared
- BYTE	X
X Pixel 0-127
- BYTE	Y
Y Pixel 0-31
- BYTE	State
0=White (Off), 1=Black (On)
- VOID	Return

	ServoSetPosition
Allows one of the servo positions to be assigned
- BYTE	Channel
Range 0-3
- BYTE	Position
Range 0-255
- VOID	Return

	CardBitmap
Displays a monochrome bitmap read from the card on the LCD
- BYTE	X
Range 0-127
- BYTE	Y
Range 0-31
- STRING	Filename
- BYTE	Return

	CardRecordMic
Records an audio stream on the card from the microphone
- BYTE	BitDepth
0=8-bit, 1=16-bit
- BYTE	SampleRate
Sample Rate 0=8KHz, 1=16KHz
- UINT	RecordTime
Time to record for in seconds, Range 0-65535
- STRING	Filename
- BYTE	Return

	CardOpen
Attempts to open an existing file on the SD card 255=Error, 1=File not found, 0=Open OK
- STRING	Filename
- BYTE	Return

	Forwards
Drives the robot forwards - waits for the distance to be traversed before returning
- UINT	Distance
Distance in mm
- VOID	Return

	ReadBearing
Reads the compass bearing based on the degrees clockwise from magnetic north.
[[File:]] -	Return

	GetConsoleHandle
Gets the handle to the console allowing data displaying on the panel etc.
[[File:]] -	Return

	LCDDrawLine
Allows a single pixel width line to be drawn on the LCD
- BYTE	X1
X Pixel 0-127
- BYTE	Y1
Y Pixel 0-31
- BYTE	X2
X Pixel 0-127
- BYTE	Y2
Y Pixel 0-31
- VOID	Return

	ServoAutoMoveToPosition
Allows one of the servo positions to move gradually to a new position
- BYTE	Channel
Range 0-3
- BYTE	Position
Range 0-255
- VOID	Return

	ReadAllValue
Reads a single value stored from the read all command Index dictates which sensor value to read
- BYTE	Index
0=SW, 1-8=IR, 9-10=Line, 11=Light, 12=Mic, 13-15=Accel
- UINT	Return

	LCDBacklight
Allows the LCD backlight brighntess to be adjusted
- BYTE	Intensity
Range 0-100, 0=Off, 1=Min Brightness, 100=Max Brightness
- VOID	Return

	LCDDrawRect
Allows a rectangle to be drawn on the LCD
- BYTE	X1
X Pixel 0-127
- BYTE	Y1
Y Pixel 0-31
- BYTE	X2
X Pixel 0-127
- BYTE	Y2
Y Pixel 0-31
- VOID	Return

	ReadLine
Reads one of the IR line sensors 0-1 0=Left, 1=Right
- BYTE	index
0=Left, 1=Right
- UINT	Return

	ServoDisable
Allows one of the servo outputs 0-3 to be disabled
- BYTE	Channel
Range 0-3
- VOID	Return

	ServoEnable
Allows one of the servo outputs 0-3 to be enabled
- BYTE	Channel
Range 0-3
- VOID	Return

	CardReadByte
Reads a byte from the currently open file. Starts at the beginning of the file and auto increments to the end
- BYTE	Return

	CardErase
Attempts to delete an existing file on the SD card 255=Error, 1=File not found, 0=Delete OK
- STRING	Filename
- BYTE	Return

	CardWriteByte
Appends a byte to the end of the currently open file
- BYTE	Data
- VOID	Return

	EncoderRead
Reads one of the motor encoder counters. Approx 0.328296mm of travel per encoder unit.
- BYTE	index
0=Left, 1=Right
- UINT	Return

	SetMotors
Sets the motor speeds without feedback Range -100 to 100
[[File:]] -	Left
Range -100 to 100
[[File:]] -	Right
Range -100 to 100
- VOID	Return

	Backwards
Drives the robot backwards - waits for the distance to be traversed before returning
- UINT	Distance
Distance in mm
- VOID	Return

	EncoderReset
Resets the motor encoder counters
- VOID	Return

	LCDVerbose
Allows the LCD to automatically report the API commands as they get processed. Default - verbose on
- BYTE	State
0=Off 1=On
- VOID	Return

	SetProp
Allows the COM port property to be set from a parent component.
- STRING	PropName
- ULONG	PropVal
- VOID	Return

	CardInit
Attempts to startup the SD card 255=No Card, 254=Init Fail, 0=Init OK
- BYTE	Return

	GetProp
Allows the property filter for the COM port list to be copied to a parent component.
- STRING	PropName
- STRING	Return

	LCDClear
Clears the LCD
- VOID	Return

Property reference

	Properties
	Address Bits
	Stop Delay
On older microcontroller devices there is a potential for the I2C hardware channel to lock up if there is not a 10ms delay between an I2C stop event and the next I2C start event. Most modern microcontrollers will not have a problem so this property can be disabled to speed up the I2C communications.
	Baud Select
Baud rate option selector
	Baud Rate
Baud rate to be used
	Scope Traces
Selects if the component pin connections are automatically generated on the data recorder window or not. Yes: Automatically add the component pins to a group on the data recorder which will reflect the sim data during simultion. No: Do not show the pin signals on the data recorder window.
	Console Data
Selects if the console data is automatically generated or not
	Injector
Specifies the injector component on the panel to interact with to provide comms simulation.
	Connections
	Channel
Channel selection
	SDA
Pin used for SDA (data signal)
	SCL
Pin used for SCL (clock signal)
	Simulations
	Simulate Comms