API Reference for the SFE_ST25DV64KC_IO class

Brief Overview

The SFE_ST25DV64KC_IO class provides the interface to the ST25DV hardware via I²C. It provides methods to: read and write single and multiple register values, set or clear individual register bits, and confirm if a register bit is set.

Initialization

begin()

This method records the specified TwoWire port and uses that for all future I²C communication.

It also calls isConnected() and returns the result, confirming whether the ST25DV has been detected successfully.

bool begin(TwoWire &wirePort)

Parameter	Type	Description
`wirePort`	`TwoWire &`	The I²C port to be used to communicate with the ST25DV
return value	`bool`	`true` if the ST25DV is detected, otherwise `false`

isConnected()

This method confirms if the ST25DV is connected by polling one of its I²C addresses.

bool isConnected()

Parameter	Type	Description
return value	`bool`	`true` if the ST25DV is detected, otherwise `false`

Register Read / Write

readSingleByte()

This method reads a single register and returns the contents.

bool readSingleByte(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, uint8_t *value)

Possible values for address are:

DATA,          // E2 = 0, E1 = 1
SYSTEM,        // E2 = 1, E1 = 1
RF_SWITCH_OFF, // E2 = 0, E1 = 0
RF_SWITCH_ON,  // E2 = 1, E1 = 0

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The register address
`value`	`uint8_t *`	`value` will hold the register value on return
return value	`bool`	`true` if the read was successful, otherwise `false`

writeSingleByte()

This method writes a value to the specified register.

bool writeSingleByte(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, const uint8_t value)

Possible values for address are:

DATA,          // E2 = 0, E1 = 1
SYSTEM,        // E2 = 1, E1 = 1
RF_SWITCH_OFF, // E2 = 0, E1 = 0
RF_SWITCH_ON,  // E2 = 1, E1 = 0

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The register address
`value`	`const uint8_t`	The value to be written
return value	`bool`	`true` if the write was successful, otherwise `false`

readMultipleBytes()

This method reads and returns multiple register values, starting at registerAddress.

Note

buffer must be sufficiently large to hold all packetLength bytes.

bool readMultipleBytes(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, uint8_t *const buffer, const uint16_t packetLength)

Possible values for address are:

DATA,          // E2 = 0, E1 = 1
SYSTEM,        // E2 = 1, E1 = 1
RF_SWITCH_OFF, // E2 = 0, E1 = 0
RF_SWITCH_ON,  // E2 = 1, E1 = 0

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The start register address
`buffer`	`uint8_t *const`	A pointer to the array of uint8_t which will hold the read values
`packetLength`	`const uint16_t`	The number of registers to be read
return value	`bool`	`true` if the read was successful, otherwise `false`

writeMultipleBytes()

This method writes values to multiple registers, starting at registerAddress.

bool writeMultipleBytes(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, uint8_t *const buffer, const uint16_t packetLength)

Possible values for address are:

DATA,          // E2 = 0, E1 = 1
SYSTEM,        // E2 = 1, E1 = 1
RF_SWITCH_OFF, // E2 = 0, E1 = 0
RF_SWITCH_ON,  // E2 = 1, E1 = 0

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The start register address
`buffer`	`uint8_t *const`	A pointer to the array of uint8_t which holds the values to be written
`packetLength`	`const uint16_t`	The number of values to be written
return value	`bool`	`true` if the write was successful, otherwise `false`

Register Bit Manipulation

setRegisterBit()

This method will set the bit(s) defined by bitMask in the selected register.

This method uses a read-modify-write to set the bit(s).

bool setRegisterBit(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, const uint8_t bitMask)

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The register address
`bitMask`	`const uint8_t`	Defines which bits will be set. Each bit set in `bitMask` will cause the corresponding bit in `registerAddress` to be set
return value	`bool`	`true` if the write was successful, otherwise `false`

clearRegisterBit()

This method will clear the bit(s) defined by bitMask in the selected register.

This method uses a read-modify-write to clear the bit(s).

bool clearRegisterBit(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, const uint8_t bitMask)

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The register address
`bitMask`	`const uint8_t`	Defines which bits will be cleared. Each bit set in `bitMask` will cause the corresponding bit in `registerAddress` to be cleared
return value	`bool`	`true` if the write was successful, otherwise `false`

isBitSet()

This method returns true if the bit selected in bitMask is set.

Note

If multiple bits are set in bitMask, the method will return true if any one of those bits is set.

bool isBitSet(const SF_ST25DV64KC_ADDRESS address, const uint16_t registerAddress, const uint8_t bitMask)

Parameter	Type	Description
`address`	`enum class SF_ST25DV64KC_ADDRESS`	The register type, equivalent to the I²C address
`registerAddress`	`const uint16_t`	The register address
`bitMask`	`const uint8_t`	Defines which bits will be tested
return value	`bool`	`true` if the bit defined by `bitMask` is set, otherwise `false`

Member Variables

Note

When the ST25DV is busy writing to its internal DATA memory, it will NACK any further attempted I²C transmissions until the write is complete. The write duration is variable and depends on whether the write crosses block boundaries. Therefore, the library implements a retry strategy. Each read or write will be attempted up to maxRetries times, with a delay of retryDelay in between, before an error is triggered.

Parameter	Type	Description
`readWriteChunkSize`	`uint8_t`	The number of bytes that will be read or written in a single I²C transmission. Default is 32
`maxRetries`	`const uint8_t`	The maximum number of times a register read or write wil be attempted before triggering an error. Set to 6
`retryDelay`	`const uint8_t`	The number of milliseconds delay between read or write attempts. Set to 5