Datasheet

Product data sheet Rev. 03 — 20 March 2008 15 of 107

NXP Semiconductors

TEF6901A

Integrated car radio

After a tuning action, which is activated by the state machine, the IF counter is reset at

that moment when tuning is established (PLL in-lock). The ﬁrst counter result is available

from 2 ms after reset. For FM further results can be obtained from 4 ms, 8 ms, 16 ms and

32 ms after reset, the increasing count time attenuates inﬂuence of FM modulation on the

counter result. After this, the counter continues at the maximum count time of 32 ms (see

Figure 5). For AM the count time is ﬁxed to 2 ms and results are available every 2 ms.

After AF Update (AFU) sampling the IF counter read value is held (IFCM = 10) (see

Figure 6, Figure 17 and Figure 18) for easy I

C-bus read-out. The counter itself remains

active in the background in 2 ms count time mode. The IF counter data hold is released

after I

C-bus read.

IFCM reads 00 immediately after I

C-bus start of PRESET, SEARCH, AFU, JUMP or

CHECK until the ﬁrst new tuning IFC result is available.

1 1 0 1 13 kHz to 14 kHz 104 kHz to 112 kHz 6.5 kHz to 7 kHz 52 kHz to 56 kHz

1 1 1 0 14 kHz to 15 kHz 112 kHz to 120 kHz 7 kHz to 7.5 kHz 56 kHz to 60 kHz

1 1 1 1 15 kHz to 16 kHz ≥ 120 kHz 7.5 kHz to 8 kHz ≥ 60 kHz

Table 8. IF counter result

…continued

IFC3 IFC2 IFC1 IFC0 Deviation from nominal value in FM Deviation from nominal value in AM

IFCA = 0 IFCA = 1 IFCA = 0 IFCA = 1

Fig 5. IF counter in FM mode after tuning

001aab785

2 ms 2 ms 4 ms 8 ms 16 ms 32 ms32 ms

tuning

f1 f2

time

C-bus

2 ms

4 ms

8 ms

16 ms

32 ms

32 ms 32 ms

reset

counter time