micrf405 Micrel Semiconductor, micrf405 Datasheet - Page 9

• Manufacturer Part Number: micrf405
• Description: Micrf405 290mhz To 980mhz Ism Band Ask/fsk Transmitter
• Manufacturer: Micrel Semiconductor

April 2006
Writing to the Control Registers in MICRF405
Writing: A number of octets are entered into
MICRF405 followed by a load-signal to activate the
new setting. Making these events is referred to as a
“write sequence.” It is possible to update all, 1, or n
control registers in a write sequence. The address to
write to (or the first address to write to) can be any
valid address (0-29). The SIO line is always an input
to the MICRF405 (output from user) when writing.
Field
Address:
R/W bit:
Values:
How to write:
Bring SEN low to start a write sequence. The active
state of the SEN line is “low”. Use the SCK/SIO
serial interface to clock in “Address” and “R/W” bit
and “Values” into the MICRF405. MICRF405 will
sample the SIO line at negative edges of SCK. Make
sure to change the state of the SIO line before the
negative edge, for instance on positive edge. Refer
to Figure 2.
Bring SEN inactive to make an internal load-signal
and complete the write-sequence. Note: there is an
exception to this point. If the programming bit called
“load_en” (D0 in ControlRegister0) is “0”, then no
load pulse is generated.
Field
Address:
R/W bit:
Values:
How to write:
Micrel
• Bring SEN low
• Use SCK and SIO to clock in the 2 octets
• Bring SEN high
Table 4. When writing to a Single Register, totally 2 octets are clocked into the MICRF405.
Comments
A 7-bit field, ranging from 0 to 29. MSB is written first.
A 1-bit field, = “0” for writing
A number of octets (1-30 octets). MSB in every octet is written first. The first octet is written to the control
register with the specified address (=”Address”). The next octet (if there is one) is written to the control
register with address = “Address + 1” and so on.
Comments
7 bit = A6, A5, …A0 (A6 = MSB. A0 = LSB)
“0” for writing
8 bits = D7, D6, …D0 (D7 = MSB, D0 = LSB)
Table 3. Writing to the Control Registers.
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What to write:
The two different ways to “program the chip”
are:
Writing to a Single Register
Writing to a control register with address “A6, A5,
…A0” is described here. During operation, writing to
1 register is sufficient to change the way the
transmitter works. Typical example: Change from
transmit mode to power-down.
• The address of the control register to write to (or
• A bit to enable reading or writing of the control
• The values to write into the control register(s).
• Write to a number of control registers (0-29)
• Write to a number of control registers when the
if more than 1 control register should be written
to, the address of the 1st control register to write
to).
registers. This bit is called the R/W bit.
when the registers have incremental addresses
(write to 1, all or n registers)
registers have non-incremental addresses.
MICRF405
[phone]
M9999-041906