ISL5314 Datasheet, PDF (16/17 Pages) Intersil Corporation – Direct Digital Synthesizer

ISL5314
Control Register Description
ADDRESS
0
BITS
7:0
Center frequency bits CF(7:0) (LSB).
DESCRIPTION
RESET
STATE
(Note 14)
00h
1
7:0 Center frequency bits CF(15:8).
00h
2
7:0 Center frequency bits CF(23:16).
00h
3
7:0 Center frequency bits CF(31:24).
00h
4
7:0 Center frequency bits CF(39:32).
00h
5
7:0 Center frequency bits CF(47:40) (MSB). (Reset gives f_CLK/4 output).
40h
6
7:0 Offset frequency bits OF(7:0) (LSB).
00h
7
7:0 Offset frequency bits OF(15:8).
00h
8
7:0 Offset frequency bits OF(23:16).
00h
9
7:0 Offset frequency bits OF(31:24).
00h
10
7:0
11
7:0
12
7:0
7:5
4
3
2
1
0
13
7:0
7
6
5
4:0
14
7:0
5:4
15
7:0
NOTE:
14. b = binary, h = hex
Offset frequency bits OF(39:32).
Offset frequency bits OF(47:40) (MSB).
Serial input control word.
Select number of serial frequency input bits:
1xx = 40-bit word (weighting same as CF(47:8))
011 = 32-bit word (weighting same as CF(47:16))
010 = 24-bit word (weighting same as CF(47:24))
001 = 16-bit word (weighting same as CF(47:32))
000 = 8-bit word (weighting same as CF(47:40))
Serial input sync position select:
1 = sync early. Sync is expected one serial clock period before the first data bit.
0 = sync late. Sync is expected one serial clock after the last data bit.
Serial sync polarity: 1 = active low, 0 = active high.
Serial clock polarity: 0 = rising edge, 1 = falling edge.
Shift direction: 0 = MSB first, 1 = LSB first.
Center frequency enable: 1 = enable, 0 = disable.
This bit can be used to zero the center frequency (CF(47:0)) to the phase accumulator. This does not zero
the processor interface registers—just the data path from the center frequency register to the phase
accumulator. The center frequency resets to f_CLK/4.
NCO control word.
Intersil reserved. Do not change.
Serial output frequency register enable: 1 = enable, 0 = disable.
This bit enables/disables the data path from the serial frequency register to the phase accumulator,
without changing the value of the register. Should be disabled after RESET if not used.
Phase accumulator feedback: 0 = accumulator feedback disabled, 1 = accumulator enabled.
Intersil reserved. Do not change.
Test and timing control register. User must write 00h or 30h to register 14 after RESET.
NCO-to-DAC setup and hold timing control. Write either 11b or 00b to these bits.
Register 15 does not actually exist. Any write to register 15 is an UPDATE. This function is provided to
save one microprocessor control pin from being used for the UPDATE pin, if the user chooses.
00h
00h
01h
000b
0b
0b
0b
0b
1b
F8h
1b
1b
1b
11000b
10h
01b
N/A
16
FN4901.3
January 19, 2010