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| java.lang.Object | |
| ↳ | android.nfc.tech.MifareUltralight |
Provides access to MIFARE Ultralight properties and I/O operations on a Tag.
Acquire a MifareUltralight object using get(Tag).
MIFARE Ultralight compatible tags have 4 byte pages PAGE_SIZE.
The primary operations on an Ultralight tag are readPages(int) and
writePage(int, byte[]).
The original MIFARE Ultralight consists of a 64 byte EEPROM. The first 4 pages are for the OTP area, manufacturer data, and locking bits. They are readable and some bits are writable. The final 12 pages are the user read/write area. For more information see the NXP data sheet MF0ICU1.
The MIFARE Ultralight C consists of a 192 byte EEPROM. The first 4 pages are for OTP, manufacturer data, and locking bits. The next 36 pages are the user read/write area. The next 4 pages are additional locking bits, counters and authentication configuration and are readable. The final 4 pages are for the authentication key and are not readable. For more information see the NXP data sheet MF0ICU2.
Implementation of this class on a Android NFC device is optional.
If it is not implemented, then
MifareUltralight will never be enumerated in getTechList().
If it is enumerated, then all MifareUltralight I/O operations will be supported.
In either case, NfcA will also be enumerated on the tag,
because all MIFARE Ultralight tags are also NfcA tags.
Note: Methods that perform I/O operations
require the NFC permission.
| Constants | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| int | PAGE_SIZE | Size of a MIFARE Ultralight page in bytes | |||||||||
| int | TYPE_ULTRALIGHT | A MIFARE Ultralight tag | |||||||||
| int | TYPE_ULTRALIGHT_C | A MIFARE Ultralight C tag | |||||||||
| int | TYPE_UNKNOWN | A MIFARE Ultralight compatible tag of unknown type | |||||||||
| Public Methods | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Disable I/O operations to the tag from this
TagTechnology object, and release resources. | |||||||||||
Enable I/O operations to the tag from this
TagTechnology object. | |||||||||||
Get an instance of
MifareUltralight for the given tag. | |||||||||||
Return the maximum number of bytes that can be sent with
transceive(byte[]). | |||||||||||
Get the
Tag object backing this TagTechnology object. | |||||||||||
Get the current
transceive(byte[]) timeout in milliseconds. | |||||||||||
Return the MIFARE Ultralight type of the tag.
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Helper to indicate if I/O operations should be possible.
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Read 4 pages (16 bytes).
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Set the
transceive(byte[]) timeout in milliseconds. | |||||||||||
Send raw NfcA data to a tag and receive the response.
| |||||||||||
Write 1 page (4 bytes).
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Inherited Methods | |||||||||||
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From class
java.lang.Object
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From interface
android.nfc.tech.TagTechnology
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From interface
java.io.Closeable
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From interface
java.lang.AutoCloseable
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Size of a MIFARE Ultralight page in bytes
A MIFARE Ultralight tag
A MIFARE Ultralight C tag
A MIFARE Ultralight compatible tag of unknown type
Disable I/O operations to the tag from this TagTechnology object, and release resources.
Also causes all blocked I/O operations on other thread to be canceled and
return with IOException.
Requires the NFC permission.
| IOException |
|---|
Enable I/O operations to the tag from this TagTechnology object.
May cause RF activity and may block. Must not be called
from the main application thread. A blocked call will be canceled with
IOException by calling close() from another thread.
Only one TagTechnology object can be connected to a Tag at a time.
Applications must call close() when I/O operations are complete.
Requires the NFC permission.
| IOException |
|---|
Get an instance of MifareUltralight for the given tag.
Returns null if MifareUltralight was not enumerated in
getTechList() - this indicates the tag is not MIFARE
Ultralight compatible, or that this Android
device does not implement MIFARE Ultralight.
Does not cause any RF activity and does not block.
| tag | an MIFARE Ultralight compatible tag |
|---|
Return the maximum number of bytes that can be sent with transceive(byte[]).
transceive(byte[]).
Get the Tag object backing this TagTechnology object.
Tag backing this TagTechnology object.
Get the current transceive(byte[]) timeout in milliseconds.
Requires the NFC permission.
Return the MIFARE Ultralight type of the tag.
One of TYPE_ULTRALIGHT or TYPE_ULTRALIGHT_C or
TYPE_UNKNOWN.
Depending on how the tag has been formatted, it can be impossible to accurately classify between original MIFARE Ultralight and Ultralight C. So treat this method as a hint.
Does not cause any RF activity and does not block.
Read 4 pages (16 bytes).
The MIFARE Ultralight protocol always reads 4 pages at a time, to reduce the number of commands required to read an entire tag.
If a read spans past the last readable block, then the tag will return pages that have been wrapped back to the first blocks. MIFARE Ultralight tags have readable blocks 0x00 through 0x0F. So a read to block offset 0x0E would return blocks 0x0E, 0x0F, 0x00, 0x01. MIFARE Ultralight C tags have readable blocks 0x00 through 0x2B. So a read to block 0x2A would return blocks 0x2A, 0x2B, 0x00, 0x01.
This is an I/O operation and will block until complete. It must
not be called from the main application thread. A blocked call will be canceled with
IOException if close() is called from another thread.
Requires the NFC permission.
| pageOffset | index of first page to read, starting from 0 |
|---|
| TagLostException | if the tag leaves the field |
|---|---|
| IOException | if there is an I/O failure, or the operation is canceled |
Set the transceive(byte[]) timeout in milliseconds.
The timeout only applies to transceive(byte[]) on this object,
and is reset to a default value when close() is called.
Setting a longer timeout may be useful when performing transactions that require a long processing time on the tag such as key generation.
Requires the NFC permission.
| timeout | timeout value in milliseconds |
|---|
Send raw NfcA data to a tag and receive the response.
This is equivalent to connecting to this tag via NfcA
and calling transceive(byte[]). Note that all MIFARE Classic
tags are based on NfcA technology.
Use getMaxTransceiveLength() to retrieve the maximum number of bytes
that can be sent with transceive(byte[]).
This is an I/O operation and will block until complete. It must
not be called from the main application thread. A blocked call will be canceled with
IOException if close() is called from another thread.
Requires the NFC permission.
| IOException |
|---|
Write 1 page (4 bytes).
The MIFARE Ultralight protocol always writes 1 page at a time, to minimize EEPROM write cycles.
This is an I/O operation and will block until complete. It must
not be called from the main application thread. A blocked call will be canceled with
IOException if close() is called from another thread.
Requires the NFC permission.
| pageOffset | index of page to write, starting from 0 |
|---|---|
| data | 4 bytes to write |
| TagLostException | if the tag leaves the field |
|---|---|
| IOException | if there is an I/O failure, or the operation is canceled |