mfrc531 NXP Semiconductors, mfrc531 Datasheet - Page 50

• Manufacturer Part Number: mfrc531
• Description: Iso/iec 14443 Reader Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
MFRC531_34
Product data sheet
PUBLIC
10.5.1.5 FIFOLength register
Table 46.
Number of bytes in the FIFO buffer.
Table 47.
Table 48.
Bit
2
1
0
Bit
Symbol
Access
Bit
7
6 to 0 FIFOLength[6:0]
Symbol
Err
HiAlert
LoAlert
Symbol
0
PrimaryStatus register bit descriptions
FIFOLength register (address: 04h) reset value: 0000 0000b, 00h bit allocation
FIFOLength bit descriptions
R
Rev. 3.4 — 26 January 2010
7
0
Value Status
1
1
1
Description
reserved
gives the number of bytes stored in the FIFO buffer. Writing
increments the FIFOLength register value while reading decrements
the FIFOLength register value
056634
6
5
Description
any error flag in the ErrorFlag register is set
the alert level for the number of bytes in the FIFO
buffer (FIFOLength[6:0]) is:
otherwise value = logic 0
Example:
the alert level for number of bytes in the FIFO
buffer (FIFOLength[6:0]) is:
value = logic 0
Example:
HiAlert
LoAlert
FIFOLength = 60, WaterLevel = 4 then
HiAlert = logic 1
FIFOLength = 59, WaterLevel = 4 then
HiAlert = logic 0
FIFOLength = 4, WaterLevel = 4 then
LoAlert = logic 1
FIFOLength = 5, WaterLevel = 4 then
LoAlert = logic 0
4
…continued
FIFOLength[6:0]
=
=
(
FIFOLength WaterLevel
64 FIFOLength
–
R
3
ISO/IEC 14443 reader IC
≤
2
MFRC531
) WaterLevel
© NXP B.V. 2010. All rights reserved.
≤
1
otherwise
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