Depending on the command, byte 1 through byte N

may assume different functions. They may either be a

direct command (write, read, read all, reset), or an

address or data contents. The commands available in

the MAX7057 SPI are described in detail below:

Write: The write command (0x01) is used to program

the MAX7057 registers (see Tables 2 and 3). The for-

mat shown in Figure 3 must be followed, allowing all the

registers to be programmed within one

CS cycle.

Using a byte descriptive notation, the write command

can be viewed as the following sequence:

Data 0 is then written to the register addressed by

<Initial Address>, Data 1 is written to <Initial Address +

1>, and so on.

Read: To execute an SPI read operation, the general-

purpose output (GPO) pin must be configured to either

a CKOUT_SDO or SDO function (see Tables 15 and 16

for details).

SDI: <0x01> <Initial Address> <Data 0> <Data 1> … <Data N>

300MHz to 450MHz Frequency-Programmable

ASK/FSK Transmitter

______________________________________________________________________________________

11

Figure 2. SPI Format

SDI

SCLK

CS

WRITE COMMAND (0x01)

INITIAL ADDRESS (A[7:0])

DATA 0

DATA N

D7

D7

D6

D5

D4

D3

D2

D1

D0

A7

A6

A5

A4

A3

A2

A1

A0

D0

SDI

DATA 1

DATA N

SCLK

D7

D6

D5

D4

D3

D2

D1

D0

D7

D6

D5

D4

D3

D2

D1

D0

CS

Figure 3. SPI Write Command Format