MICRF505

Micrel

M9999-051304

10

May 13, 2004

How to write:

• Bring CS high

• Use SCLK and IO to clock in the 23 octets

• Bring CS low

Refer to the figure in the next section, “Writing to n registers

having incremental addresses”.

Writing to n registers having incremental

addresses

In addition to entering all bytes, it is also possible to enter a

set of n bytes, starting from address i = “A6, A5, ... A0.”

Typical example: Clock in a new set of frequency dividers

(i.e. change the RF frequency). “Incremental addresses”:

Registers to be written are located in i, i+1, i+2 ...

What to write

Field

Comments

Address:

7 bit = A6, A5, ... A0 (A6 = msb, A0 = lsb) (address of first byte to write to)

R/W bit:

“0” for writing

Values:

n* 8 bits =

D7, D6, ... D0 (D7 = msb, D0 = lsb) (written to control reg. with address “i”)

D7, D6, ... D0 (D7 = msb, D0 = lsb) (written to control reg. with address “i+1”)

...

D7, D6, ... D0 (D7 = msb, D0 = lsb) (written to control reg. with address “i+n-1 “)

Table 5. “Address” and “R/W bit” Together Make 1 Octet.

In addition, n octets with programming bits are entered. Totally, 1 + n octets are clocked into the MICRF505.

How to write:

• Bring CS high

• Use SCLK and IO to clock in the 1 + n octets

• Bring CS low

In Figure 1, n = 2 (write to 2 registers in the MICRF505). In

the figure, IO is changed at positive edges of SCLK. The

MICRF505 samples the IO line at negative edges. The value

of the R/W bit is always “0” for writing.

Figure 2.

D0

D7

D0

D7

RW

A0

A5

A6

CS

SCLK

IO

Address of first

register to write to,

register i

RW

Data to write

into register i

Internal load pulse made here

Data to write

into register i+1