hsp45102 Intersil Corporation, hsp45102 Datasheet - Page 5

• Manufacturer Part Number: hsp45102
• Description: 12-bit Nco 28 Soic, 40mhz, Comm
• Manufacturer: Intersil Corporation

input register. At each clock, the contents of this register are
summed with the current contents of the accumulator to step to
the new phase. The phase accumulator stepping may be
inhibited by holding ENPHAC high. The phase accumulator
may be loaded with the value in the input register by asserting
LOAD, which zeroes the feedback to the phase accumulator.
The phase adder sums the encoded phase modulation bits
P0-1 and the output of the phase accumulator to offset the
phase by 0°, 90°, 180° or 270°. The two bits are encoded to
produce the phase mapping shown in Table 1. This phase
mapping is provided for direct connection to the in-phase
and quadrature data bits for QPSK modulation.
MSB/LSB
SFTEN
MSB/LSB
SCLK
SFTEN
SD
SCLK
SD
SEL_L/M
ENPHAC
OUT0-11
CLK
LOAD
TXFR
5
1
FIGURE 2B. FREQUENCY LOADING CONTROLLED BY SCLK
FIGURE 2A. FREQUENCY LOADING ENABLED BY SFTEN
2
0
3
0
1
4
FIGURE 3. I/O TIMING
1
HSP45102
2
5
2
6
ROM Section
The ROM section generates the 12-bit sine value from the
13-bit output of the phase adder. The output format is offset
binary and ranges from 001 to FFF hexadecimal, centered
around 800 hexadecimal.
7
P1
0
0
1
1
61
8
61
62
TABLE 1. PHASE MAPPING
9
62
P0
0
1
0
1
63
P0-1 CODING
10
63
PHASE SHIFT (DEGREES)
11
DATA
NEW
270
180
90
0
April 25, 2007
FN2810.9