U4255BM-M Datasheet, PDF (16/32 Pages) ATMEL Corporation – AM / FM RECEIVER IC

Table 30. Sensitivity of the MNC
Sensitivity MNC (Threshold)
Off
Low
(-18 dB)
Normal (-12 dB)
High (-9 dB)
Bit 93
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Bit 92
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Bit 84
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Bit 83
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Bit 82
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Bit 81
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
3-wire Bus Description
The register settings of U4255BM-M are programmed by a 3-wire bus protocol. The bus
protocol consists of separate commands. A defined number of bits is transmitted
sequentially during each command.
One command is used to program all bits of one register. The different registers avail-
able (see Table 31) are addressed by the length of the command (number of transmitted
bits) and by three address bits that are unique for each register of a given length. 8-bit
registers are programmed by 8-bit commands and 24-bit registers are programmed by
24-bit commands.
Each bus command starts with a rising edge on the enable line (EN) and ends with a
falling edge on EN. EN has to be kept HIGH during the bus command.
The sequence of transmitted bits during one command starts with the LSB of the first
byte and ends with the MSB of the last byte of the register addressed. The DATA is
evaluated at the rising edges of CLK. The number of LOW to HIGH transitions on CLK
during the HIGH period of EN is used to determine the length of the command.
The bus protocol and the register addressing of U4255BM-M are compatible to the
addressing used in U4256BM. That means U4255BM-M and U4256BM can be operated
on the same 3-wire bus as shown in the application circuit.
16 U4255BM-M
4519C–AUDR–07/02