PSoC® Creator™ Component Data Sheet
I2C Master/Multi-Master/Slave
2.0
Features
•
Industry standard Philips® I2C bus compatible interface
•
Supports Slave, Master, and Multi-Master operation
•
Only two pins (sda and scl) required to interface to I2C bus
•
Standard data rate of 100/400/1000 kbps
•
High level API requires minimal user programming
•
Supports PSoC 3 ES3 silicon revisions and above
General Description
The I2C component supports I2C Slave, Master, and Multi-Master configurations. The I2C bus is
an industry standard, two-wire hardware interface developed by Philips. The master initiates all
communication on the I2C bus and supplies the clock for all slaved devices.
The I2C component supports the standard mode with speeds up to 1000 kbps. The I2C
component is compatible with other third party slave and master devices.
Note This version of the data sheet covers both the fixed hardware I2C block and the UDB
version.
When to use a I2C component
The I2C component is an ideal solution when networking multiple devices on a single board or
small system. The system can be designed with a single master and multiple slaves, multiple
multi-masters or a combination of multi-masters and slaves.
PRELIMINARY
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-62887 Rev. *A
Revised November 30, 2010
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Input/Output Connections
This section describes the various input and output connections for the I2C component. An
asterisk (*) in the list of I/Os indicates that the I/O may be hidden on the symbol under the
conditions listed in the description of that I/O.
sda – In/Out
This is the I2C data signal. It is a bi-directional data signal used to transmit or receive all bus
data.
scl – In/Out
The SCL signal is the master generated I2C clock. Although the slave never generates the clock
signal, it may hold it low until it is ready to NAK or ACK the latest data or address.
clock – Input *
The clock input is available when the ‘Implementation’ parameter is set to UDB. The UDB
version needs a clock to provide 16 times oversampling. If you want your bus to be 400 kHz, you
need a 6.4 MHz clock. If you want a 100 kHz bus, you need a 1.6 MHz clock.
reset – Input *
The reset input is available when the ‘Implementation’ parameter is set to UDB. If the reset pin is
held to a logic high, the I2C block would be held in reset, and communication over I2C would not
be possible.
Schematic Macro Information
By default, the PSoC Creator Component Catalog contains four Schematic Macro
implementations for the I2C component. These macros contain already connected and adjusted
pins and a clock source, when needed. The Schematic Macros use I2C Slave and Master
components, configured as fixed function and UDB, as shown.
2
2
Fixed Function I C Slave with Pins
Fixed Function I C Master Pins
PRELIMINARY
Page 2 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
2
2
UDB I C Slave with Clock and Pins
UDB I C Master with Clock and Pins
Parameters and Setup
Drag an I2C component onto your design and double-click it to open the Configure dialog.
The I2C component provides the following parameters.
Mode
This option determines what modes are supported, Slave, Master, or Multi-Master.
Mode
Description
Slave
Slave only operation (default).
Master
Master only operation.
Multi-Master
Multi-Master only operation.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 3 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Bus Speed
An I2C bus speed between 50 to 1000 kHz may be selected; the actual speed may differ. The
standard speeds are 50, 100 (default), 400 and 1000 kHz. This speed is referenced from the
system bus clock.
Implementation
This option determines how the I2C hardware is implemented on the device.
Implementation
Description
FixedFunction
Use the fixed function block on the device (default).
UDB
Create the I C in a UDB.
2
Address Decode
This parameter gives you the option to choose between software or hardware address decoding.
For most applications where the provided API is sufficient, "Hardware" address decoding is
preferred. In applications where you prefer to modify the source code to provide multiple slave
address detection, "Software" address detection is preferred. Hardware is the default.
Slave Address
This is the I2C address that will be recognized by the slave. If slave operation is not selected, this
parameter is ignored. A slave address between 0 and 127 may be selected; the default is 4.
Pin Connections
This parameter determines which type of pin to use for SDA and SCL signal connections. There
are three possible values: Any, I2C0, and I2C1. The default is "Any."
"Any" means general purpose I/O (GPIO). If Enable wakeup from Sleep Mode is not required
for any I/O pin, "Any" can be used for SDA and SCL. Otherwise, "I2C0" or "I2C1" must be used,
which will allow you to configure the device for wakeup on I2C address match.
Enable wakeup from Sleep Mode
This option enables the system to be awakened from sleep when an address match occurs. This
option is only valid if Hardware Address Decode is selected and the SDA and SCL signals are
connected to SIO ports (I2C0 or I2C1). The default is disabled.
Refer to the device errata for this feature availability. The possibility of I2C to wake up device on
slave address match should be enabled while switching to the sleep mode, refer to the "Power
Management APIs" section of the System Reference Guide.
PRELIMINARY
Page 4 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
Clock Selection
If using a fixed function block, the clock is tied to the system bus clock and cannot be changed.
The UDB implementation needs an external clock source to provide 16 times oversampling. For
example, a 1.6 MHz clock is required for 100 kHz Bus Speed.
Resources
The fixed I2C block is used for the Fixed Function implementation.
For the UDB implementation, see the following table.
API Memory
(Bytes)
Digital Blocks
Mode
Datapaths
Macro
cells
Status
Registers
Control
Registers
Counter7
Flash
RAM
Pins (per
External I/O)
Slave
1
25
1
1
1
TBD
TBD
TBD
Master
2
16
1
1
0
TBD
TBD
TBD
Multi-Master
2
22
1
1
0
TBD
TBD
TBD
Application Programming Interface
Application Programming Interface (API) routines allow you to configure the component using
software. The following table lists and describes the interface to each function. The subsequent
sections cover each function in more detail.
By default, PSoC Creator assigns the instance name "I2C_1" to the first instance of a component
in a given design. You can rename the instance to any unique value that follows the syntactic
rules for identifiers. The instance name becomes the prefix of every global function name,
variable, and constant symbol. For readability, the instance name used in the following table is
"I2C".
All API functions assume that data direction is from the perspective of the I2C master. A write
event occurs when data is written from the master to the slave. A read event occurs when the
master reads data from the slave.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 5 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Generic Functions
This section includes the functions that are generic to I2C slave or master operation.
Function
Description
2
void I2C_Int(void)
Initializes I C registers with initial values provided from customizer.
void I2C_Enable(void)
Enables I C operations.
void I2C_Start(void)
Starts responding to I C traffic (Interrupt remains disabled).
void I2C_Stop(void)
Stops responding to I C traffic (Disables interrupt).
void I2C_SaveCofig(void)
Saves none–retention I C registers.
void I2C_Sleep(void)
Stops I C operation and saves I C configuration (Disables interrupt).
void I2C_RestoreConfig(void)
Restores none–retention I C registers.
void I2C_Wakeup(void)
Restores I C configuration and starts I C operation (Interrupt remains disabled).
void I2C_EnableInt(void)
Enables interrupt.
void I2C_DisableInt(void)
Disables interrupt. Stop does this automatically.
2
2
2
2
2
2
2
2
2
void I2C_Init(void)
2
Description:
Initializes I C registers with initial values provided from customizer.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_Enable(void)
2
Description:
Enables I C operations.
Parameters:
None
Return Value:
None
Side Effects:
None
PRELIMINARY
Page 6 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
void I2C_Start(void)
2
Description:
Starts the I C hardware. Enables Active mode power template bits or clock gating as
2
appropriate. It is required to be executed before I C bus operation.
2
The I C interrupt remains disabled after this function call.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_Stop(void)
2
2
Description:
Disables I C hardware and disables I C interrupt. Disables Active mode power template
bits or clock gating as appropriate.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_SaveConfig(void)
2
Description:
Wakeup on address match enabled: disables I C master functionality, enables power
2
regulator for all I C registers, all transaction are NAKed while I2C will be ready go to
sleep.
2
Wakeup on address match disabled: Saves I C configuration and non-retention
register values.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_Sleep(void)
2
Description:
Wakeup on address match enabled: restores I C master functionality, disables power
2
regulator for all I C registers.
2
Wakeup on address match disabled: Saves I C configuration and non-retention
register values. Disables active mode power template bits or clock gating as appropriate.
2
Disables I C interrupt.
Parameters:
None
Return Value:
None
Side Effects:
None
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 7 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
void I2C_RestoreConfig(void)
2
Description:
Wakeup on address match enabled: restores I C master functionality, disables power
2
regulator for all I C registers.
2
Wakeup on address match disabled: Restores I C configuration and non-retention
register values.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_Wakeup(void)
2
Description:
Wakeup on address match enabled: disables I C master functionality, enables power
2
regulator for all I C registers, all transaction are NAKed while I2C will be ready go to
sleep.
2
Wakeup on address match disabled: Restores I C configuration and non-retention
register values. Restores Active mode power template bits or clock gating as appropriate.
2
The I C interrupt remains disabled after function call.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_EnableInt(void)
2
Description:
Enables I C interrupt. Interrupts are required for most operations.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_DisableInt(void)
2
Description:
Disables I C interrupts. Normally this function is not required since the Stop function
2
2
disables the interrupt. If the I C interrupt is disabled while the I C master is still running, it
2
may cause the I C bus to lock up.
Parameters:
None
Return Value:
None
Side Effects:
If the I C interrupt is disabled and the master is addressing the current slave, the bus will
be locked until the interrupt is re-enabled.
2
PRELIMINARY
Page 8 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
Slave Functions
This section lists the functions that are used for I2C slave operation. These functions will be
available if slave operation is enabled.
Function
Description
uint8 I2C_SlaveStatus(void)
Returns slave status bits.
uint8 I2C_SlaveClearReadStatus(void)
Returns the read status and clear slave read status flags.
uint8 I2C_SlaveClearWriteStatus(void)
Returns the write status and clear the slave write status flags.
void I2C_SlaveSetAddress(uint8 address)
Sets slave address, a value between 0 and 127.
void I2C_SlaveInitReadBuf(uint8 * rdBuf,
uint8 byteCount)
Setups the slave receive data buffer. (master -> slave)
void I2C_SlaveInitWriteBuf(uint8 * wrBuf,
uint8 byteCount)
Setups the slave write buffer. (master <- slave)
uint8 I2C_SlaveGetReadBufSize(void)
Returns the amount of bytes read by the master since the buffer
was reset.
uint8 I2C_SlaveGetWriteBufSize(void)
Returns the amount of bytes written by the master since the buffer
was reset.
void I2C_SlaveClearReadBuf(void)
Resets the read buffer counter to zero.
void I2C_SlaveClearWriteBuf(void)
Resets the write buffer counter to zero.
void I2C_SlavePutReadByte (uint8
transmitDataByte)
For Master Read, sends 1 byte out Slave transmit buffer.
uint8 I2C_SlaveGetWriteByte (uint8 ackNak)
For a Master Write, ACKs or NAKs the previous byte and reads
out the last byte transmitted.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 9 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
uint8 I2C_SlaveStatus(void)
Description:
Returns the slave’s communication status.
Parameters:
None
Return Value:
(uint8) Current status of I C slave.
2
Slave status constants
Side Effects:
Description
I2C_SSTAT_RD_CMPT
Slave read transfer complete
I2C_SSTAT_RD_BUSY
Slave read transfer in progress
I2C_SSTAT_RD_ERR_OVFL
Master attempted to read more bytes than are in
buffer.
I2C_SSTAT_RD_ERR
Slave read error.
I2C_SSTAT_WR_CMPT
Slave write transfer complete
I2C_SSTAT_WR_BUSY
Slave Write transfer in progress
I2C_SSTAT_WR_ERR_OVFL
Master attempted to write past end of buffer.
I2C_SSTAT_WR_ERR
Slave write Error
None
uint8 I2C_SlaveClearReadStatus(void)
Description:
Returns read status flags then clears the read status flags.
Parameters:
None
Return Value:
(uint8) Current read status of slave (See I2C_SlaveStatus command for constants).
Side Effects:
None
uint8 I2C_SlaveClearWriteStatus(void)
Description:
Returns write status flags then clears the write status flags.
Parameters:
None
Return Value:
(uint8) Current write status of slave (See I2C_SlaveStatus command for constants).
Side Effects:
None
PRELIMINARY
Page 10 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
void I2C_SlaveSetAddress(uint8 address)
2
Description:
Sets the I C slave address
Parameters:
(uint8) address: I C slave address for the primary device. This value may be any address
between 0 and 127.
Return Value:
None
Side Effects:
None
2
void I2C_SlaveInitReadBuf(uint8 * rdBuf, uint8 bufSize)
Description:
Sets the buffer pointer and size of the read buffer. This command also resets the transfer
count returned with the I2C_SlaveGetReadBufSize function.
Parameters:
(uint8*) rdBuf: – Pointer to the data buffer to be read by the master.
2
(uint8) bufSize: – Size of the buffer exposed to the I C master.
Return Value:
None
Side Effects:
None
void I2C_SlaveInitWriteBuf(uint8 * wrBuf, uint8 bufSize)
Description:
Sets the buffer pointer and size of the write buffer. This command also resets the transfer
count returned with the I2C_SlaveGetWriteBufSize function.
Parameters:
(uint8* ) wrBuf: – Pointer to the data buffer to be written by the master.
2
(uint8) bufSize – Size of the buffer exposed to the I C master.
Return Value:
None
Side Effects:
None
uint8 I2C_SlaveGetReadBufSize(void)
2
Description:
Returns the number of bytes read by the I C master since an I2C_SlaveInitReadBuf or
I2C_SlaveClearReadBuf function was executed.
Parameters:
None
Return Value:
(uint8) Bytes read by master.
Side Effects:
None
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 11 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
uint8 I2C_SlaveGetWriteBufSize(void)
2
Description:
Returns the number of bytes written by the I C master since an I2C_SlaveInitWriteBuf or
I2C_SlaveClearWriteBuf function was executed.
Parameters:
None
Return Value:
uint8: Bytes written by master.
Side Effects:
None
void I2C_SlaveClearReadBuf(void)
Description:
Resets the read pointer to the first byte in the read buffer. The next byte read by the
master will be the first byte in the read buffer.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_SlaveClearWriteBuf(void)
Description:
Resets the write pointer to the first byte in the write buffer. The next byte written by the
master will be the first byte in the write buffer.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_SlavePutReadByte (uint8 transmitDataByte)
Description:
For Master Read, sends 1 byte out Slave transmit buffer. Wait to send byte until buffer
has room. Used to preload the transmit buffer. In byte by byte mode if the last byte was
ACKed, stall the master (on the first bit of the next byte) if needed until the next byte is
PutChared. If the last byte was NAKed it does not stall the bus because the master will
generate a stop or restart condition.
Parameters:
(uint8) transmitDataByte: Byte containing the data to transmit.
Return Value:
None
Side Effects:
None
PRELIMINARY
Page 12 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
uint8 I2C_SlaveGetWriteByte (uint8 ackNak)
Description:
For a Master Write, ACKs or NAKs the previous byte and reads out the last byte
transmitted. The first byte read of a packet is the Address byte in which case there is no
previous data so no ACK or NAK is generated. The bus is stalled until the next GetByte,
therefore a GetByte must be executed after the last byte in order to send the final ACK or
NAK before the Master can send a Stop or restart condition.
Parameters:
(uint8) ackNak: 1 = byte was ACKed, 0 = bytes was NAKed for the previous byte
received.
Return Value:
(uint8) Last byte transmitted or last byte in buffer from Master.
Side Effects:
None
Master and Multi-Master Functions
These functions are only available if Master or Multi-Master mode is enabled.
Function
Description
uint8 I2C_MasterStatus(void)
Returns master status.
uint8 I2C_MasterClearStatus(void)
Returns the master status and clear the status flags.
uint8 I2C_MasterSendStart(uint8
slaveAddress, uint8 R_nW)
Sends just a start to the specific address.
uint8 I2C_MasterSendRestart(uint8
slaveAddress, uint8 R_nW)
Sends just a restart to the specified address.
uint8 I2C_MasterSendStop(void)
Generates a stop condition.
uint8 I2C_MasterWriteBuf(uint8 slaveAddr,
uint8 * wrData, uint8 cnt, uint8 mode)
Writes the reference data buffer to a specified slave address.
uint8 I2C_MasterReadBuf(uint8 slaveAddr,
uint8 * rdData, uint8 cnt, uint8 mode)
Reads data from the specified slave address and place the data in
the referenced buffer.
uint8 I2C_MasterWriteByte(uint8 theByte)
Writes a single byte. This is a manual command that should only be
used with MasterSendStart or MasterSendRestart functions.
uint8 I2C_MasterReadByte(uint8 acknNack) Reads a single byte. This is a manual command that should only be
used with MasterSendStart or MasterSendRestart functions.
uint8 I2C_MasterGetReadBufSize(void)
Returns the byte count of data read since the MasterClearReadBuf
function was called.
uint8 I2C_MasterGetWriteBufSize(void)
Returns the byte count of the data written since the
MasterClearWriteBuf function was called.
void I2C_MasterClearReadBuf(void)
Resets the read buffer pointer back to the beginning of the buffer.
void I2C_MasterClearWriteBuf(void)
Resets the write buffer pointer back to the beginning of the buffer.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 13 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
uint8 I2C_MasterStatus(void)
Description:
Returns the master’s communication status.
Parameters:
None
Return Value:
(uint8) Current status of I C master.
2
Master status constants
Description
I2C_MSTAT_RD_CMPLT
Read transfer complete
I2C_MSTAT_WR_CMPLT
Write transfer complete
I2C_MSTAT_XFER_INP
Transfer in progress
I2C_MSTAT_XFER_HALT
Transfer has been halted
I2C_MSTAT_ERR_SHORT_XFER Transfer completed before all bytes transferred.
Side Effects:
I2C_MSTAT_ERR_ADDR_NAK
Slave did not acknowledge address
I2C_MSTAT_ERR_ARB_LOST
Master lost arbitration during communications
with slave.
I2C_MSTAT_ERR_XFER
Error occurred during transfer
I2C_MSTAT_ERR_BUF_OVFL
Buffer overflow/underflow
None
uint8 I2C_MasterClearStatus(void)
Description:
Returns the master status and clears all status flags
Parameters:
None
Return Value:
(uint8) Current status of master (See I2C_MasterStatus command for constants).
Side Effects:
None
PRELIMINARY
Page 14 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
uint8 I2C_MasterSendStart(uint8 slaveAddress, uint8 R_nW)
Description:
Generates Start condition and sends slave address with read/write bit.
Parameters:
(uint8) slaveAddress: Slave address.
(uint8) R_nW: Zero, send write command, non-zero send read command.
Return Value:
(uint8) Error Status.
Mode Constants
Side Effects:
Description
I2C_MSTR_NO_ERROR
Function complete without error.
I2C_MSTR_BUS_BUSY
Bus timeout occurred, process not started.
I2C_MSTR_SLAVE_BUSY
Slave operation in progress.
I2C_MSTR_ERR_LB_NAK
Last Byte Naked.
I2C_MSTR_ERR_ARB_LOST
Master lost arbitration while Start generation.
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
uint8 I2C_MasterSendRestart(uint8 slaveAddress, uint8 R_nW)
Description:
Generates ReStart condition and sends slave address with read/write bit.
Parameters:
(uint8) slaveAddress: Slave address (Valid range 0 to 127).
(uint8) R_nW: Zero, send write command, non-zero send read command.
Return Value:
(uint8) Error Status (See I2C_MasterSendStart command for constants).
Side Effects:
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
uint8 I2C_MasterSendStop(void)
2
Description:
Generates I C Stop condition on bus. This function does nothing if Start or Restart
conditions failed before this function was called.
Parameters:
None
Return Value:
(uint8) Error Status (See I2C_MasterSendStart command for constants).
Side Effects:
The Stop generation is required on read and write operations.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 15 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
uint8 I2C_MasterWriteBuf(uint8 slaveAddress, uint8 * wrData, uint8 cnt, uint8 mode)
Description:
Automatically writes an entire buffer of data to a slave device. Once the data transfer is
initiated by this function, further data transfer is handled by the included ISR.
Parameters:
(uint8) slaveAddress: Slave address.
(uint8) wrData: Pointer to buffer of data to be sent.
(uint8) cnt: Size of buffer to send.
(uint8) mode: Transfer mode, complete the transfer or halt before generating a stop.
Mode Constants
Description
I2C_MODE_COMPLETE_XFER
Perform complete transfer for Start to Stop.
I2C_MODE_REPEAT_START
Send Repeat Start instead of Start.
I2C_MODE_NO_STOP
Execute transfer without a Stop
Return Value:
(uint8) Error Status (See I2C_MasterSendStart command for constants).
Side Effects:
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
uint8 I2C_MasterReadBuf(uint8 slaveAddress, uint8 * rdData, uint8 cnt, uint8 mode)
Description:
Automatically reads an entire buffer of data from a slave device. Once the data transfer is
initiated by this function, further data transfer is handled by the included ISR.
Parameters:
(uint8) slaveAddress: Slave address.
(uint8) rdData: Pointer to buffer where to put data from slave.
(uint8) cnt: Size of buffer to read.
(uint8) mode: Transfer mode, complete the transfer or halt before generating a stop.
Mode Constants
Description
I2C_MODE_COMPLETE_XFER
Perform complete transfer for Start to Stop.
I2C_MODE_REPEAT_START
Send Repeat Start instead of Start.
I2C_MODE_NO_STOP
Execute transfer without a Stop
Return Value:
uint8: Error Status. (See I2C_MasterSendStart command for constants).
Side Effects:
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
PRELIMINARY
Page 16 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
uint8 I2C_MasterWriteByte(uint8 theByte)
Description:
Sends one byte to a slave. A Start or ReStart must be generated before this command is
valid. This function does nothing if Start or Restart conditions failed before this function
was called.
Parameters:
(uint8) theByte– The data byte to send to the slave.
Return Value:
(uint8) Error Status.
Mode Constants
Side Effects:
Description
I2C_MSTR_NO_ERROR
Function complete without error.
I2C_MSTR_SLAVE_BUSY
Slave operation in progress.
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
uint8 I2C_MasterReadByte(uint8 acknNak)
Description:
Reads one byte from a slave and ACK or NAK the transfer. A Start or ReStart must be
generated before executing this command. This function does nothing if Start or Restart
conditions failed before this function was called.
Parameters:
(uint8) acknNack– Zero, sends a NAK, if non-zero send a ACK.
Return Value:
(uint8) Byte read from buffer.
Side Effects:
This function is entered without a ‘byte complete’ flag set in the I2C_CSR register, it does
not exit.untill it will be set.
uint8 I2C_MasterGetReadBufSize(void)
Description:
Returns the amount of bytes that has been transferred with an I2C_MasterReadBuf
command.
Parameters:
None
Return Value:
(uint8) Byte count of transfer. If the transfer is not yet complete, it will return the byte
count transferred so far.
Side Effects:
None
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 17 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
uint8 I2C_MasterGetWriteBufSize(void)
Description:
Returns the amount of bytes that has been transferred with a I2C_MasterWriteBuf
command.
Parameters:
None
Return Value:
(uint8) Byte count of transfer. If the transfer is not yet complete, it will return the byte
count transferred so far.
Side Effects:
None
void I2C_MasterClearReadBufSize(void)
Description:
Resets the read buffer pointer back to the first byte in the buffer.
Parameters:
None
Return Value:
None
Side Effects:
None
void I2C_MasterClearWriteBufSize(void)
Description:
Resets the write buffer pointer back to the first byte in the buffer.
Parameters:
None
Return Value:
None
Side Effects:
None
Sample Firmware Source Code
The following is a C language example demonstrating the basic functionality of the I2C
component. This example assumes the component has been placed in a design with the default
name "I2C_1."
Note If you rename your component you must also edit the example code as appropriate to
match the component name you specify.
/***********************************************************
* Example code to demonstrate the use of the I2C Component
* as a master device. This example creates an array with the
* string "Hello World" then sends it to a slave device
* with an address of 4.
*************************************************************/
#include <device.h>
/* Part specific constants and macros */
void main()
{
char wrData[] = "Hello World";
PRELIMINARY
Page 18 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
I2C_1_MasterClearStatus(); /* Clear any previous status */
I2C_1_Start();
I2C_1_EnableInt();
CYGlobalIntEnable;
I2C_1_MasterWriteBuf(4, (uint8 *) wrData, 12, I2C_1_MODE_COMPLETE_XFER);
for(;;)
{
if(I2C_1_MasterStatus() & I2C_MSTAT_WR_CMPLT)
{
/* Transfer complete */
break;
}
}
}
/***********************************************************
* Example code to demonstrate the use of the I2C
* Component as a slave device.
* This example waits for an I2C master to send a packet
* of data. When a transfer is complete, the data is
* copied into the userArray.
*************************************************************/
#include <device.h>
/* Part specific constants and macros */
void main()
{
uint8 i;
uint8 wrBuf[12];
uint8 userArray[12];
uint8 byteCnt;
I2C_1_SlaveInitWriteBuf((uint8 *) wrBuf, 12);
I2C_1_Start();
I2C_1_EnableInt();
CYGlobalIntEnable;
/* Wait for I2C master to complete a write */
for(;;) /* loop forever */
{
/* Wait for I2C master to complete a write */
if(I2C_1_SlaveStatus() & I2C_SSTAT_WR_CMPT)
{
byteCnt = I2C_1_SlaveGetWriteBufSize();
I2C_1_SlaveClearWriteStatus ();
for(i=0; i < byteCnt; i++)
{
userArray[i] = wrBuf[i]; /* Transfer data */
}
I2C_1_SlaveClearWriteBuf();
}
}
}
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 19 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Functional Description
This component supports I2C slave, master, and multi-master configurations. The following
sections give an overview in how to use the slave and master/multi-master components.
This component requires that you enable global interrupts since the I2C hardware is interrupt
driven. Even though this component requires interrupts, you do not need to add any code to the
ISR (Interrupt Service Routine). The module services all interrupts (data transfers) independent
of your code. The memory buffers allocated for this interface look like simple dual port memory
between your application and the I2C Master.
Slave Operation
The slave interface consists of two buffers in memory, one for data written to the slave by a
master and a second buffer to contain data read by a master from the slave. Remember that
reads and writes are from the perspective of the I2C Master. A read occurs when the master
reads data from the slave. The I2C slave read and write buffers are set by the initialization
commands below. These commands do not allocate memory, but instead copy the array pointer
and size to the internal component variables. The arrays used for the buffers must be
instantiated by the programmer, since they are not automatically generated by the component.
The same buffer may be used for both read and write buffers, but care must be taken to manage
the data properly.
void I2C_SlaveInitReadBuf(uint8 * rdBuf, uint8 bufSize)
void I2C_SlaveInitWriteBuf(uint8 * wrBuf, uint8 bufSize)
Using the functions above sets a pointer and byte count for the read and write buffers. The
bufSize for these functions may be less than or equal to the actual array size, but they should
never be larger than the available memory pointed to by the rdBuf or wrBuf pointers.
PRELIMINARY
Page 20 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
Figure 1: Slave Buffer Structure
Memory
0xFFFF
uint8 rdBuf[10];
I2C_SlaveInitReadBuf(rdBuf, 10);
Index
0x1243
0x09
uint8 wrBuf[8];
I2C_SlaveInitWriteBuf(wrBuf, 8);
0x08
0x07
Index
0x06
I2C Read
Buffer
0x05
0x04
0x03
0x07
0x123A
0x1237
0x05
0x04 I2C Write
Buffer
0x03
0x02
0x01
0x00
0x06
0x02
0x1230
0x01
0x00
0x0000
When the I2C_SlaveInitReadBuf or I2C_SlaveInitWriteBuf functions are called the internal index
is set to the first value in the array pointed to by rdBuf and wrBuf respectively. As bytes are read
or written by the I2C master the index is incremented until the offset is one less than the
byteCount. At anytime the number of bytes transferred may be queried by calling either
I2C_SlaveGetReadBufSize or I2C_SlaveGetWriteBufSize for the read and write buffers
respectively. Reading or writing more bytes than are in the buffers will cause an overflow error.
The error will be set in the slave status byte and may be read with the I2C_SlaveStatus
command.
To reset the index back to the beginning of the array, use the following commands.
void I2C_SlaveClearReadBuf(void)
void I2C_SlaveClearWriteBuf(void)
This will reset the index back to zero. The next byte read or written to by the I2C master will be
the first byte in the array. Before these clear buffer commands are used, the data in the arrays
should be read or updated.
Multiple reads or writes by the I2C master will continue to increment the array index until the clear
buffer commands are used or the array index attempts to grow beyond the array size. The figure
below shows an example where an I2C master has executed two write transactions. The first
write was 4 bytes and the second write was 6 bytes. The 6th byte in the second transaction was
NAKed by the slave to signal that the end of the buffer has occurred. If the master tried to write a
7th byte for the second transaction or started to write more bytes with a third transaction, each
byte would be NAKed and discarded until the buffer is reset.
Using the I2C_SlaveClearWriteBuf function after the first transaction will reset the index
back to zero and cause the second transaction to overwrite the data from the first transaction.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 21 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Care should be taken to make sure data is not lost by overflowing the buffer. The data in the
buffer should be processed by the slave before resetting the buffer index.
Figure 2 System Memory
Both the read and write buffers have four status bits to signal transfer complete, transfer in
progress, buffer overflow, and transfer error. When a transfer starts the busy flag is set. When
the transfer is complete, the transfer complete flag is set and the busy flag is cleared. If a second
transfer is started, both the busy and transfer complete flags may be set at the same time. See
table below for read and write status flags.
Slave status constants
Value
Description
I2C_SSTAT_RD_CMPT
0x01
Slave read transfer complete
I2C_SSTAT_RD_BUSY
0x02
Slave read transfer in progress (busy)
I2C_SSTAT_RD_OVFL
0x04
Master attempted to read more bytes than are in buffer.
I2C_SSTAT_RD_ERR
0x08
Slave read error.
I2C_SSTAT_WR_CMPT
0x10
Slave write transfer complete
I2C_SSTAT_WR_BUSY
0x20
Slave Write transfer in progress (busy)
I2C_SSTAT_WR_OVFL
0x40
Master attempted to write past end of buffer.
I2C_SSTAT_WR_ERR
0x80
Slave write Error
The following code example initializes the write buffer then waits for a transfer to complete. Once
the transfer is complete, the data is then copied into a working array to handle the data. In many
PRELIMINARY
Page 22 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
applications, the data does not have to be copied to a second location, but instead can be
processed in the original buffer. A read buffer example would look almost identical by replacing
the write functions and constants with read functions and constants. Processing the data may
mean new data is transferred into the slave buffer instead of out.
uint8 wrBuf[10];
uint8 userArray[10];
uint8 byteCnt;
I2C_SlaveInitWriteBuf((uint8 *) wrBuf, 10);
/* Wait for I2C master to complete a write */
for(;;) /* loop forever */
{
/* Wait for I2C master to complete a write */
if(I2C_SlaveStatus() & I2C_SSTAT_WR_CMPT)
{
byteCnt = I2C_SlaveGetWriteBufSize( );
I2C_ SlaveClearWriteStatus ( );
For(i=0; I < byteCnt; i++)
{
userArray[i] = wrBuf[i]; /* Transfer data */
}
I2C_SlaveClearWriteBuf();
}
}
Master/Multi-Master Operation
Master and Multi-Master operation are basically the same except for two exceptions. When
operating in Multi-Master mode, the bus should always be checked to see if it is busy. Another
master may be already communicating with another slave. In this case, the program must wait
until the current operation is complete before issuing a Start transaction. The program looks at
the return value which sets an error if another Master has control of the bus.
The second difference is that in Multi-Master mode, it is possible that two masters start at the
exact same time. If this happens, one of the two masters will lose arbitration. This condition must
be checked for after each byte is transferred. The component will automatically check for this
condition and respond with an error if arbitration is lost.
There are a couple options when operating the I2C master: manual and automatic. In the
automatic mode, a buffer is created to hold the entire transfer. In the case of a write operation,
the buffer will be pre-filled with the data to be sent. If data is to be read from the slave, a buffer at
least the size of the packet needs to be allocated. To write an array of bytes to a slave in the
automatic mode, use the following function.
uint8 I2C_MasterWriteBuf(uint8 SlaveAddr, uint8 * wrData, uint8 cnt, uint8 mode)
The SlaveAddr variable is a 7-bit slave address of 0 to 127. The component API will
automatically append the write flag to the msb of the address byte. The array of data to transfer
is pointed to with the second parameter "wrData". The "cnt" is the amount of bytes to transfer.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 23 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
The last parameter, "mode" determines how the transfer starts and stops. A transaction may
begin with a ReStart instead of a Start, or halt before the Stop sequence. These options allow
back-to-back transfers where the last transfer does not send a Stop and the next transfer issues
a Restart instead of a Start.
A read operation is almost identical to the write operation. The same parameters with the same
constants are used. See function below.
uint8 I2C_MasterReadBuf(uint8 SlaveAddr, uint8 * rdData, uint8 cnt, uint8 mode);
Both of these functions return status. See the status table for the MasterStatus() function return
value. Since the read and write transfers complete in the background during the I2C interrupt
code, the MasterStatus() function can be used to determine when the transfer is complete.
Below is a code snippet that shows a typical write to a slave.
I2C_MasterClearStatus(); /* Clear any previous status */
I2C_MasterWriteBuf(4, (uint8 *) wrData, 10, I2C_MODE_COMPLETE_XFER);
for(;1;)
{
if(I2C_MasterStatus() & I2C_MSTAT_WR_CMPLT)
{
/* Transfer complete */
break;
}
}
The I2C master can also be operated in a manual way. In this mode each part of the write
transaction is performed with individual commands. See the example code below.
I2C_MasterClearStatus();
status = I2C_MasterSendStart(4, I2C_WRITE_XFER_MODE);
if(status == I2C_MSTR_NO_ERROR)
/* Check if transfer completed without errors */
{
/* Send array of 5 bytes */
for(i=0; i<5; i++)
{
status = I2C_MasterWriteByte(userArray[i]);
if(status != I2C_MSTR_NO_ERROR )
{
break;
}
}
}
I2C_MasterSendStop();
/* Send Stop */
A manual read transaction is similar to the write transaction except the last byte should be
NAKed. The example below shows a typical manual read transaction.
I2C_MasterClearStatus();
status = I2C_MasterSendStart(4, I2C_READ_XFER_MODE);
if(status == I2C_MSTR_NO_ERROR)
/* Check if transfer completed without errors */
{
/* Read array of 5 bytes */
PRELIMINARY
Page 24 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
for(i=0; i<5; i++)
{
if(i < 4)
{
userArray[i] = I2C_MasterReadByte(I2C_ACK_DATA);
}
else
{
userArray[i] = I2C_MasterReadByte(I2C_NAK_DATA);
}
}
}
I2C_MasterSendStop();
/* Send Stop */
External Electrical Connections
As the block diagram illustrates, the I2C bus requires external pull up resistors. The pull up
resistors (RP) are determined by the supply voltage, clock speed, and bus capacitance. Make
the minimum sink current for any device (master or slave) no less than 3 mA at VOLmax = 0.4V
for the output stage. This limits the minimum pull up resistor value for a 5V system to about 1.5
k . The maximum value for RP depends upon the bus capacitance and clock speed. For a 5V
system with a bus capacitance of 150 pF, the pull up resistors are no larger than 6 k . For more
information on "The I2C -Bus Specification", see the Philips web site at www.philips.com.
Figure 3 Connection of devices to the I2C-bus
+VDD
pull-up
resistors
Rp
Rp
SDA (Serial Data Line)
SCL (Serial Clock Line)
Device 1
Device 2
Note Purchase of I2C components from Cypress or one of its sublicensed Associated
Companies, conveys a license under the Philips I2C Patent Rights to use these components in
an I2C system, provided that the system conforms to the I2C Standard Specification as defined
by Philips.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 25 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Interrupt Service Routine
The interrupt service routine is used by the component code itself and should not be modified.
Block Diagram and Configuration
Not applicable
Registers
The functions provided support the common runtime functions required for most applications.
The following register references provide brief descriptions for the advanced user. The I2C_Data
register may be used to write data directly to the bus without using the API. This may be useful
for either the CPU or DMA.
The registers available to each of the configurations of the I2C component are grouped according
to the implementation as fixed function or UDB.
Fixed Function Master / Slave Registers
Please refer to the chip Technical Reference Manual (TRM) for more information on these
registers.
I2C_XFCG
The extended configuration register is available in the fixed function hardware block to configure
the hardware address mode and clock source.
Bits
7
Value
csr_clk_en
6
5
4
3
2
1
RSVD
0
hw_addr_en
•
csr_clk_en: Used to enable gating for the fixed function block core logic
•
hw_addr_en: Used to enable hardware address comparison.
I2C_ADDR
The slave address register is available in the fixed function hardware block to configure the slave
device address for hardware comparison mode if enabled in the XCFG register above.
Bits
7
Value
RSVD
•
6
5
4
3
2
1
0
slave_address
slave_address: Used to define the 7-bit slave address for hardware address comparison
mode
PRELIMINARY
Page 26 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
I2C_CFG
The configuration register is available in the fixed function hardware block to configure the basic
functionality.
Bits
7
6
5
4
Value
sio_select
pselect
bus_error_ie
stop_ie
3
2
clock_rate[1:0]
1
0
en_mstr
en_slave
•
sio_select: Used to select between SIO1 and SIO2 lines for SCL and SDA, pselect must
be set for this bit to have an affect
•
pselect: Used to select between SIO or GPIO pins for SCL and SDA lines
•
bus_error_ie: Used to enable interrupt generation for bus_error
•
stop_ie: Used to enable interrupt generation on stop bit detection
•
clock_rate[1:0]: Used to select the bit-rate clock from 100Kbps, 400Kbps or 50Kbps
•
en_mstr: Used to enable master mode
•
en_slave: Used to enable slave mode
I2C_CSR
The control and status register is available in the fixed function hardware block for runtime
control and status feedback.
Bits
7
6
5
4
3
2
1
0
Value
bus_error
lost_arb
stop_status
ack
address
transmit
lrb
byte_complete
•
bus_error: Bus error detection status bit. This must by cleared by writing a ‘0’ to this bit
position.
•
lost_arb: Lost arbitration detection status bit.
•
stop_status: Stop detection status bit. This must by cleared by writing a ‘0’ to this position.
•
ack: Acknowledge control bit. This bit must be set to ‘1’ to ACK the last byte received or
‘0’ to NACK the last byte received.
•
address: Hardware address match detection status bit: This must by cleared by writing a
‘0’ to this bit position.
•
transmit: Used by firmware to define the direction of a byte transfer.
•
lrb: Last Received Bit status. This bit indicates the state of the 9th bit (ACK/NACK)
response from the receiver for the last byte transmitted.
•
byte_complete: Transmit or receive status since last read of this register. In Transmit
mode this bit indicates 8-bits of data have been transmitted since last read. In Receive
mode this bit indicates 8-bits of data have been received since last read of this register.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 27 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
I2C_DATA
The data register is available in the fixed function hardware block for runtime transmit and receipt
of data.
Bits
7
6
5
4
Value
•
3
2
1
0
data
data: In Transmit mode this register is written with the data to transmit. In Receive mode
this register is read upon status receipt of byte_complete.
I2C_MCSR
The Master control and status register is available in the fixed function hardware block for
runtime control and status feedback of Master mode operations.
Bits
7
6
Value
5
4
RSVD
3
bus_busy
2
1
master_mode restart_gen
0
start_gen
•
bus_busy: Indicates bus status, 0 means a stop condition was detected, 1 indicates a
start condition was detected.
•
master_mode: When hardware device is operating as master, 0 indicates a stop condition
was detected, 1 indicates a start condition was detected.
•
restart_gen: Control registers to create a restart condition on the bus. This bit is cleared
by hardware after the restart has been implemented (may be read as status after setting
to poll for completion of the condition).
•
start_gen: Control registers to create a start condition on the bus. This bit is cleared by
hardware after the start has been implemented (may be read as status after setting to poll
for completion of the condition).
UDB Master
The UDB register definitions are derived from the Verilog implementation of I2C. Please refer to
the specific mode implementation Verilog for more information on these registers definitions.
I2C_CFG
The control register is available in the UDB implementation for runtime control of the hardware
Bits
7
Value
RSVD
•
6
5
stop_gen restart_gen
4
3
2
1
0
nack
RSVD
transmit
en_master
RSVD
stop_gen: Used to generate a stop condition on the bus. This bit must be cleared by
firmware after a suitable amount of time.
PRELIMINARY
Page 28 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
•
restart_gen: Used to generate a restart condition on the bus. This bit must be cleared by
firmware after a suitable amount of time.
•
nack: Used to NAK the next read byte. This bit must be cleared by firmware between
bytes.
•
transmit: Used to set the current mode to transmit or receive a byte of data. This but must
be cleared by firmware after the byte has started transmitting.
•
en_master: Used to enable the hardware block.
I2C_CSR
The status register is available in the UDB implementation for runtime status feedback from the
hardware. The status data is registered at the input clock edge of the counter giving all bits
configured as Mode=1 the timing resolution of the counter, these bits are sticky and are cleared
on a read of the status register. All other bits configured as mode=0 are transparent and read
directly from the inputs to the status register, they are not sticky and therefore not clear on read.
All bits configured as Mode=1 are indicated with an asterisk (*) in the definitions listed below.
Bits
7
Value
6
5
4
lost_arb* stop_status* bus_busy
3
2
1
0
RSVD
RSVD
lrb
byte_complete
•
lost_arb*: Indicates the arbitration was lost (Multi-Master Modes).
•
stop_status*: Stop detection status bit.
•
bus_busy: Indicates the bus is busy. Data is currently being transmitted or received.
•
lbr: Last Received Bit. Indicates the state of the last received bit which is the ACK/NACK
received for the last byte transmitted.
•
byte_complete: Indicates 8-bits were received or transmitted.
I2C_INT_MASK
The Interrupt mask register is available in the UDB implementation to configure which status bits
are enabled as interrupt sources. Any of the status register bits may be enabled as in interrupt
source with a 1-to-1 bit correlation to the status registers bit-field definitions in I2C_CSR above.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 29 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
I2C_ADDRESS
The slave address register is available in the UDB implementation to configure the slave device
address for hardware comparison mode.
Bits
7
Value
RSVD
•
6
5
4
3
2
1
0
slave_address
slave_address: Used to define the 7-bit slave address for hardware address comparison
mode
I2C_DATA
The data register is available in the UDB implementation block for runtime transmit and receipt of
data.
Bits
7
6
5
4
Value
•
3
2
1
0
data
data: In Transmit mode this register is written with the data to transmit. In Receive mode
this register is read upon status receipt of byte_complete.
I2C_GO
The Go register forces data in the data register to be transmitted. Any write to this register will
force a byte transmit.
UDB Slave
The UDB register definitions are derived from the Verilog implementation of I2C. Please refer to
the specific mode implementation Verilog for more information on these registers definitions.
I2C_CFG
The control register is available in the UDB implementation for runtime control of the hardware
Bits
7
6
5
4
3
2
1
0
Value
RSVD
RSVD
RSVD
nack
any_address
transmit
RSVD
en_slave
•
nack: Used to NACK the last byte received. This bit must be cleared by firmware between
bytes.
•
any_address: Used to enable the device to respond any device addresses it receives
•
transmit: Used to set the mode to transmit or receive data. This bit must be cleared by
firmware between bytes.
•
en_slave: Used to enable or disable the hardware block.
PRELIMINARY
Page 30 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
I2C_CSR
The status register is available in the UDB implementation for runtime status feedback from the
hardware. The status data is registered at the input clock edge of the counter giving all bits
configured as Mode=1 the timing resolution of the counter, these bits are sticky and are cleared
on a read of the status register. All other bits configured as mode=0 are transparent and read
directly from the inputs to the status register, they are not sticky and therefore not clear on read.
All bits configured as Mode=1 are indicated with an asterisk (*) in the definitions listed below.
Bits
7
6
5
4
3
2
1
0
Value
RSVD
RSVD
stop*
RSVD
address
RSVD
lrb
byte_complete
•
stop*: Indicates a stop condition was detected on the bus.
•
address: Address detection. Indicates that an address byte was received.
•
lbr: Last Received Bit. Indicates the state of the last received bit which is the ACK/NACK
received for the last byte transmitted.
•
byte_complete: Indicates 8-bits were received or transmitted.
I2C_INT_MASK
The Interrupt mask register is available in the UDB implementation to configure which status bits
are enabled as interrupt sources. Any of the status register bits may be enabled as in interrupt
source with a 1-to-1 bit correlation to the status register bit-field definitions in I2C_CSR above.
I2C_ADDRESS
The slave address register is available in the UDB implementation to configure the slave device
address for hardware comparison mode.
Bits
7
Value
RSVD
•
6
5
4
3
2
1
0
slave_address
slave_address: Used to define the 7-bit slave address for hardware address comparison
mode
I2C_DATA
The data register is available in the UDB implementation block for runtime transmit and receipt of
data.
Bits
7
6
Value
•
5
4
3
2
1
0
data
data: In Transmit mode this register is written with the data to transmit. In Receive mode
this register is read upon status receipt of byte_complete.
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 31 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
I2C_GO
The Go register forces data in the data register to be transmitted. Any write to this register will
force a byte transmit.
I2C_TX_DATA
The data register is available in the UDB implementation block for runtime transmit of data. It is
defined as the same address as I2C_DATA as they are interchangeable.
Bits
7
6
5
4
Value
•
3
2
1
0
data
data: In Transmit mode this register is written with the data to transmit. In Receive mode
this register is read upon status receipt of byte_complete.
Component Debug Window
The I2C component supports the PSoC Creator component debug window. Refer to the
appropriate device data sheet for a detailed description of each register. The following registers
are displayed in the I2C component debug window. Some registers are available in the UDB
implementation (indicated by *) and some registers are only available in the Fixed Function
Implementation (indicated by **). All other registers are available for either configuration.
Register:
I2C_1_XCFG*
Name:
Extended Configuration Register
Description:
Used to configure some of the advanced configuration options of the Fixed Function block.
Refer to I2C_XCFG register description above for bit-field definitions.
Register:
I2C_1_ADDR
Name:
Slave Address Register
Description:
Used to indicate the 7-bit slave address for hardware address match detection in both fixed
function and UDB implementations.
Register:
I2C_1_CFG
Name:
Configuration Register
Description:
Used to configure the standard configuration options of the Fixed Function and UDB
implementations. Refer to I2C_CFG register descriptions above for bit-field definitions. Note
that the bit-fields are not the same for UDB and Fixed Function implementations.
PRELIMINARY
Page 32 of 34
Document Number: 001-62887 Rev. *A
2
PSoC® Creator™ Component Data Sheet
I C Master/Multi-Master/Slave
Register:
I2C_1_CSR
Name:
Status Register
Description:
For the Fixed Function block this register is the status feedback register from hardware and
includes some run-time control bits as a shared register. The UDB implementation of these
registers are independent and become the CSR (Status Register) and CFG Control register.
Refer to I2C_CSR register descriptions above for bit-field definitions.
Register:
I2C_1_DATA
Name:
Transmit and Receive Data Register
Description:
Used to load transmit data and read received data. Refer to I2C_DATA register descriptions
above for bit-field definitions.
Register:
I2C_1_MCSR*
Name:
Master Control and Status Register
Description:
Used for runtime control and status feedback of Master mode operations within the Fixed
Function Hardware Block. Refer to I2C_MCSR register description above for bit-field
definitions.
References
Not applicable
DC and AC Electrical Characteristics
5.0V/3.3V DC and AC Electrical Characteristics
Parameter
Typical
Min
Max
Units
Conditions and Notes
Input
Input Voltage Range
---
Vss to Vdd
V
Input Capacitance
---
---
pF
Input Impedance
---
---
Maximum Clock Rate
---
67
MHz
PRELIMINARY
Document Number: 001-62887 Rev. *A
Page 33 of 34
2
I C Master/Multi-Master/Slave
PSoC® Creator™ Component Data Sheet
Component Changes
This section lists the major changes in the component from the previous version.
Version
2.0.a
Description of Changes
Reason for Changes / Impact
Moved component into subfolders
of the component catalog
Minor datasheet edits and
updates
2.0
Added Sleep/Wakeup and
Init/Enable APIs.
To support low power modes, as well as to provide common
interfaces to separate control of initialization and enabling of most
components.
Component was updated to
support PSoC 3 ES3 and above.
Updated the Configure dialog:
New requirements to support the PSoC 3 ES3 device, thus a new
2.0 version was created.
Version 1.xx supports PSoC 3 ES2 and PSoC 5 ES1 silicon
revisions
2
The I C component will be able to wake up the device from Sleep
Added configuration of I2C pins
2
connection port for the wakeup on mode on I C address match.
2
I C address match feature.
Data sheet was updated.
The Parameters and Setup, Clock Selection, and Resources
sections have been updated to reflect the UDB Implementation.
Error in sample code has been fixed.
Add Reentrancy support to the
component.
Allows users to make specific APIs reentrant if reentrancy is desired.
© Cypress Semiconductor Corporation, 2009-2010. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the
use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to
be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its
products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress
products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
PSoC® is a registered trademark, and PSoC Creator™ and Programmable System-on-Chip™ are trademarks of Cypress Semiconductor Corp. All other trademarks or registered trademarks
referenced herein are property of the respective corporations.
Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and
foreign), United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create
derivative works of, and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in
conjunction with a Cypress integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as
specified above is prohibited without the express written permission of Cypress.
Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein.
Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in lifesupport systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application
implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
PRELIMINARY
Page 34 of 34
Document Number: 001-62887 Rev. *A