Datasheet

AD9834
Rev. C | Page 24 of 36
INITIALIZATION
APPLY RESET
USING PIN
SET RESET PIN = 1
USING PIN
USING CONTROL
BIT
(CONTROL REGISTER WRITE)
RESET = 1
PIN/SW = 0
(CONTROL REGISTER WRITE)
PIN/SW = 1
USING CONTROL
BIT
SET RESET = 0
SELECT FREQUENCY REGISTERS
SELECT PHASE REGISTERS
(CONTROL REGISTER WRITE)
RESET BIT = 0
FSEL = SELECTED FREQUENCY REGISTER
PSEL = SELECTED PHASE REGISTER
PIN/SW = 0
(APPLY SIGNALS AT PINS)
RESET PIN = 0
FSELECT = SELECTED FREQUENCY REGISTER
PSELECT = SELECTED PHASE REGISTER
WRITE TO FREQUENCY AND PHASE REGISTERS
FREQ0 REG = f
OUT0
/f
MCLK
× 2
28
FREQ1 REG = f
OUT1
/f
MCLK
× 2
28
PHASE0 AND PHASE1 REG = (PHASESHIFT × 2
12
)/2π
(SEE FIGURE 33)
02705-029
Figure 32. Initialization
NO
YES
DATA WRITE
NO
YES
YES
NO
YES
NONO
YES
YES
WRITE A FULL 28-BIT WORD
TO A FREQUENCY REGISTER?
(CONTROL REGISTER WRITE)
B28 (D13) = 1
WRITE TWO CONSECUTIVE
16-BIT WORDS
(SEE TABLE 11 FOR EXAMPLE)
WRITE ANOTHER FULL
28-BIT TO A
FREQUENCY REGISTER?
WRITE 14 MSBs OR LSBs
TO A FREQUENCY REGISTER?
(CONTROL REGISTER WRITE)
B28 (D13) = 0
HLB (D12) = 0/1
WRITE A 16-BIT WORD
(SEE TABLES 12 AND 13
FOR EXAMPLES)
WRITE 14 MSBs OR LSBs
TO A
FREQUENCY REGISTER?
WRITE TO PHASE
REGISTER?
D15, D14 = 11
D13 = 0/1 (CHOOSE THE
PHASE REGISTER)
D12 = X
D11 ... D0 = PHASE DATA
(16-BIT WRITE)
WRITE TO ANOTHER
PHASE REGISTER?
02705-030
Figure 33. Data Write