AD9915BCPZ データシートの表示（PDF） - Analog Devices

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AD9915BCPZ

2.5 GSPS Direct Digital Synthesizer with 12-Bit DAC

Analog Devices 

Data Sheet

AD9915

REGISTER BIT DESCRIPTIONS

The serial input/output port registers span an address range of 0

to 27 (0x00 to 0x1B in hexadecimal notation). This represents a

total of 28 individual serial registers. If programming in parallel

mode, the number of parallel registers increases to 112 individual

parallel registers. Additionally, the registers are assigned names

according to the functionality. In some cases, a register is given a

mnemonic descriptor. For example, the register at Serial

Address 0x00 is named Control Function Register 1 and is

assigned the mnemonic CFR1.

This section provides a detailed description of each bit in the

AD9915 register map. For cases in which a group of bits serves

a specific function, the entire group is considered a binary word

and is described in aggregate.

Control Function Register 1 (CFR1)—Address 0x00

This section is organized in sequential order of the serial addresses

of the registers. Each subheading includes the register name and

optional register mnemonic (in parentheses). Also given is the

serial address in hexadecimal format and the number of bytes

assigned to the register.

Following each subheading is a table containing the individual

bit descriptions for that particular register. The location of the

bit(s) in the register is indicated by a single number or a pair of

numbers separated by a colon; that is, a pair of numbers (A:B)

indicates a range of bits from the most significant (A) to the

least significant (B). For example, [5:2] implies Bit Position 5 to

Bit Position 2, inclusive, with Bit 0 identifying the LSB of the

register.

Unless otherwise stated, programmed bits are not transferred to

the internal destinations until the assertion of the I/O_UPDATE

pin or a profile pin change.

Table 17. Bit Description for CFR1

Bits Mnemonic

[31:25] Open

24

VCO cal enable

[23:18] Open

17

Parallel port streaming enable

16

Enable sine output

15

Load LRR at input/output update

14

Autoclear digital ramp

accumulator

13

Autoclear phase accumulator

12

Clear digital ramp accumulator

11

Clear phase accumulator

10

Open

Description

1 = initializes the auto internal PLL calibration. The calibration is required if the PLL is to

provide the internal system clock. Must first be reset to Logic 0 before another calibration can

be issued.

Open.

0 = the 32 bit parallel port needs an input/output update to activate or register any FTW, POW,

or AMP data presented to the 32-bit parallel port.

1 = the parallel port continuously samples data on the 32 input pins using SYNC_CLK and

multiplexes the value of FTW/POW/AMP accordingly, per the configuration of the F0 to F3 pins,

without the need of an input/output update. Data must meet the setup and hold times of the

SYNC_CLK rising edge. If the function pins are used dynamically to alter data between

parameters, they must also meet the timing of the SYNC_CLK edge.

0 = cosine output of the DDS is selected.

1 = sine output of the DDS is selected (default).

Ineffective unless CFR2[19] = 1.

0 = normal operation of the digital ramp timer (default).

1 = interrupts the digital ramp timer operation to load a new linear ramp rate (LRR) value any

time I/O_UPDATE is asserted or a PS[2:0] change occurs.

0 = normal operation of the DRG accumulator (default).

1 = the digital ramp accumulator is reset for one cycle of the DDS clock (SYNC_CLK), after

which the accumulator automatically resumes normal operation. As long as this bit remains

set, the ramp accumulator is momentarily reset each time an input/output update is asserted

or a PS[2:0] change occurs. This bit is synchronized with either an input/output update or a

PS[2:0] change and the next rising edge of SYNC_CLK.

0 = normal operation of the DDS phase accumulator (default).

1 = synchronously resets the DDS phase accumulator anytime I/O_UPDATE is asserted or a

profile change occurs.

0 = normal operation of the digital ramp generator (default).

1 = asynchronous, static reset of the DRG accumulator. The ramp accumulator remains reset as

long as this bit remains set. This bit is synchronized with either an input/output update or a

PS[2:0] change and the next rising edge of SYNC_CLK.

0 = normal operation of the DDS phase accumulator (default).

1 = asynchronous, static reset of the DDS phase accumulator as long as this bit is set. This bit is

synchronized with either an input/output update or a PS[2:0] change and the next rising edge

of SYNC_CLK.

Open.

Rev. F | Page 41 of 47

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