Datasheet

Data Sheet AD9558

Rev. B | Page 61 of 104

SOFT PIN PROGRAMMING OVERVIEW

The soft pin program function is controlled by a dedicated

purpose of soft pin program is to use the register bits to mimic

the hard pins for the configuration section. When in soft pin

program mode, both SPI and I

C port are available.

• Address 0x0C00[0] enables accessibility to Address 0x0C01

and Address 0x0C02 (Soft Pin Section 1). This bit must be

set in soft pin mode.

• Address 0x0C03[0] enables accessibility to Address 0x0C04 to

Address 0x0C06 (Soft Pin Section 2). This bit must be set

in soft pin mode.

• Address 0x0C01[3:0] select one of 16 input frequencies.

• Address 0x0C01[7:4] select one of 16 output frequencies.

• Address 0x0C02[1:0] select the system clock configuration.

• Address 0x0C06[1:0] select one of four input frequency

tolerance ranges.

• Address 0x0C06[3:2] select one of four DPLL loop

bandwidths.

• Address 0x0C06[4] selects the DPLL phase margin.

• Address 0x0C04[3:0] scales the REFA/REFB/REFC/REFD

input frequency down by divide-by-1, divide-by-4, divide-

by-8, divide-by-16 independently. For example, when

Address 0x0C01[3:0] = 0101 to select input frequency as

622.08 MHz for all REFA/REFB/REFC/REFD, setting

Address 0x0C04[1:0] = 0x01 scales down the REFA input

frequency to 155.52 MHz (= 622.08 MHz/4). This is done

by internally scaling the R divider for REFA up by 4× and

the REFA period up by 4×.

• Address 0x0C05[3:0] scales the Channel 0/1/2/3 output

frequency down by divide-by-1, divide-by-4, divide-by-8,

or divide-by-16. (Channel 2 and Channel 3 are available

only for the AD9558).