MC44S803EP FREESCALE [Freescale Semiconductor, Inc], MC44S803EP Datasheet - Page 20

• Manufacturer Part Number: MC44S803EP
• Description: Low Power CMOS Broadband Tuner
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

DIGITAL TUNE MODULE (CR-9)
the crystal clock while all other registers are latched with the
SPI/I2C clock. Therefore, the crystal oscillator must be
running before data is written to CR-9.
the capacitors in the VCOs for both VCO 1 and VCO 2. This
is used as a course tune adjustment for the VCO frequency.
Rst. Writing a 1 to this bit will cause all Tune Request bits to
clear, the count registers will clear, and the tuning state
machine will return to idle state. To resume normal operation,
first clear this bit and then proceed. This bit is for abnormal
error recovery situations and should normally not be required.
Table 28. Prescaler Selection
MC44S803
20
MSB
MSB
R19 R18 R17 R16 R15 R14 R13 R12 R11 R10 R9
R19 R18 R17 R16 R15 R14 R13 R12 R11 R10 R9
DC
DC
15
15
0
CR-9 is unique in that CR-9 register data is latched with
The Digital Tune module is a state machine that controls
8.2 MHz ≤ x < 16.5 MHz
16.5 MHz ≤ x ≤ 28 MHz
4.0 MHz ≤ x < 4.2 MHz
4.2 MHz ≤ x < 8.2 MHz
DC
MT1 AT1
14
DC
0
14
0
Crystal Freq
DC
13
0
DC
13
0
DC
12
0
DC
12
0
DC
11
0
DC
11
0
DC
10
0
DC
10
Figure 19. Digital Tune Register: LO1 Reference Register Format
0
DC
0
9
DC
0
9
Figure 18. Digital Tune Register: XO Prescale Format
Rst
Prescale
DC
0
8
DC
LO1 Reference Count
1
2
4
8
0
8
DC
0
7
DC
0
7
DC
0
6
DC
0
6
DC
0
5
DC
0
5
XOd1
DC
R8
0
4
0
0
1
1
DC
R8
0
4
DC
R7
0
3
DC
R7
0
3
DC
R6
0
2
The Digital Tune Module is controlled through five registers.
In addition to the normal control register address, it uses an
additional three address bits (DT Address) to access one of
the five Digital Tune registers. There is also a RW bit that
determines which register is read back; 1 = Read and
0 = Write. The following diagrams show a description of the
registers.
XOd. This field is used to specify a pre-scale value. It is set
according to what the crystal oscillator frequency is. Refer to
the following table. This allows the count of the VCO cycles
to exceed 2000 in the lowest VCO frequency case and be
less than 8000 in the highest VCO frequency case.
DC
R6
0
2
DC
R5
0
1
XOd0
DC
XOd
R5
0
1
0
1
0
1
DC
R4
0
0
DC
R4
0
0
RW DA2 DA1 DA0
R3
0
RW
R3
0
DT Address
DT Address
R2
0
DA
R2
0
2
R1
0
R1
DA
0
1
R0
VCO Counting Time
0
DA
R0
1
0
120 XO clocks
15 XO clocks
30 XO clocks
60 XO clocks
A3
1
A3
1
Freescale Semiconductor
Address Bits
Address Bits
A2
0
A2
0
A1
A1
0
0
LSB
LSB
A0
A0
1
1
Reset
Reset
State
State