MICRF610TR MICREL [Micrel Semiconductor], MICRF610TR Datasheet - Page 11

• Manufacturer Part Number: MICRF610TR
• Description: 868-870 MHz ISM Band Transceiver Module
• Manufacturer: MICREL [Micrel Semiconductor]

Programming Summary
Micrel, Inc.
December 2005
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Use CS, SCLK, and IO to get access to the control
registers in MICRF610.
SCLK is user-controlled.
Write to the MICRF610 at positive edges
(MICRF610 reads at negative edges).
Read from the MICRF610 at negative edges
(MICRF610 writes at positive edges)
After power-on: Write to the complete set of
control registers.
Address field is 7 bits long. Enter msb first.
R/W bit is 1 bit long (“1” for read, “0” for write)
Address and R/W bit together make 1 octet
All control registers are 8 bits long. Enter/read msb
in every octet first.
Always write 8 bits to/read 8 bits from a control
register. This is the case for registers with less
than 8 used programming bits as well.
Writing: Bring CS high, write address and R/W bit
followed by the new values to fill into the
addressed control register(s) and bring CS low for
loading, i.e., activation of the new control register
values.
Reading: Bring CS high, write address and R/W
bit, set IO as an input, read present contents of the
addressed control register(s), bring CS low and
set IO an output.
11
Frequency Synthesizer
The frequency synthesizer consists of a voltage-controlled
oscillator (VCO), a crystal oscillator, phase select
prescaler, programmable frequency dividers and a phase-
detector. The length of the N, M, and A registers are 12,
12 and 6 respectively. The N, M, and A values can be
calculated from the formula:
PhD: Phase detector comparison frequency
f
f
f
There are two sets of each of the divide factors (i.e. A0
and A1). Storing the ‘0’ and the ‘1’ frequency in the 0- and
the 1 registers respectively, does the 2-FSK. The receive
frequency must be stored in the ‘0’ registers.
Crystal Oscillator (XCO)
0001001
The crystal oscillator is a reference for the RF output
frequency and the LO frequency in the receiver. It is
possible to tune the internal crystal oscillator by switching
in internal capacitance using 5 tune bits XCOtune4 –
XCOtun0. The benefit of tuning the crystal oscillator is to
eliminate the initial tolerance and the tolerance over
temperature and aging. By using the crystal tuning feature
the noise bandwidth of the receiver can be reduced and a
higher sensitivity is achieved.
XCOtune0 = 0 no internal capacitors are connected to the
crystal pins. When XCOtune4 – XCOtune0 = 1 all of the
internal capacitors are connected to the crystal pins.
Figure 5 shows the tuning range.
XCO
VCO
RF
Adr
: Input/output RF frequency
0001010
0001011
0001100
0001101
0001110
0001111
0010000
0010001
0010010
0010011
A6…A0
: Crystal oscillator frequency
: Voltage controlled oscillator frequency
f
D7
‘0’
PhD
M0_7
M1_7
N0_7
N1_7
D6
‘1’
=
D7
-
-
-
-
-
-
f
XCO
M
D5
‘1’
N0_6
M0_6
N1_6
M1_6
D6
-
-
-
-
-
-
XCOtune4
=
D4
(
M0_5
M1_5
A0_5
N0_5
A1_5
N1_5
31
D5
-
-
-
-
1 ≤ A < N
×
f
VCO
N
XCOtune3
M0_4
M1_4
A0_4
N0_4
A1_4
N1_4
D4
D3
-
-
-
-
+
A
) (
N0_11
M0_11
N1_11
M1_11
M0_3
M1_3
A0_3
N0_3
A1_3
N1_3
D3
=
XCOtune2
When XCOtune4 –
D2
31
N0_10
M0_10
N1_10
M1_10
f
A0_2
N0_2
M0_2
A1_2
N1_2
M1_2
×
D2
RF
N
M9999-120205
XCOtune1
×
D1
+
MICRF610
2
M0_9
M0_1
M1_9
M1_1
A0_1
N0_9
N0_1
A1_1
N1_9
N1_1
D1
A
)
,
XCOtune0
N0_8
N0_0
M0_8
M0_0
N1_8
N1_0
M1_8
M1_0
A0_0
A1_0
D0
D0