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MFRC-522 RFID
Tap a card, read the UID
Page 56 drives an MFRC-522 over SPI: tapping a card shows its UID (4 or 7 bytes), card type and recent taps; MIFARE Classic sectors can also be read and written.
β The SPI bus is shared with the on-board SD card, so the two cannot be hammered at the same time; the page arbitrates the bus at startup.
Screen
On-screen interface
A recreation of this page on the 2.41-inch AMOLED display (600 Γ 450). Actual interaction and layout follow the latest firmware.
UIDA1B2C3D4MIFARE 1K
A1 B2 C3 D4MIFARE 1K21:03
04 8F 2C 9A 61 33 80NTAG21320:58
E7 11 5D 42MIFARE 1K20:41
SPI shared with SD β do not hammer both
Screen Β· Page 56
May differ from the actual interface; the screen of the real device is the final reference.
Highlights
Key capabilities
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UID readout
4/7-byte UID in hex.
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Sector access
Read and write MIFARE Classic 1K.
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Tap history
Keeps the last few cards.
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Health score
Antenna, no-card and bus conflicts separated.
Specifications
Technical specs
InterfaceSPI (shared with SD)
Frequency13.56 MHz
CardsMIFARE Classic 1K/4K, NTAG
Firmware pagePage 56
Use Cases
Typical scenarios
Access log
Record card UID and time on each tap.
Card research
Dump sectors for backup analysis.
Commands
Related commands
page 56 Open the RC522 page rfid Read a card UID
β Boundaries & notes
- SPI is shared with the SD card β heavy use of one slows the other.
- Encrypted sectors need keys; you cannot read them blind.
- Too close to metal and the card will not be seen.
Other feature pages
π Overview Home12-tile quick launch plus everyday toggles β the power-on default, and where everything starts.β‘Dashboard Β· Power & ConsumptionBLE-connected current meter with live voltage/current/power curves at fixed-point 10βΆ precision.πWaveform PanelLive curves for frame rate, heap and task load β spot the bottleneck at a glance.π΅BLE DebuggerBLE scan/connect/service discovery with full GATT tree browsing and read/write.