ADF4106
On first applying power to the ADF4106, it needs at three writes
(one each to the R counter latch, the N counter latch and the
function latch) for the output to become active.
I/O port lines on the ADuC812 are also used to control
power-down (CE input) and to detect lock (MUXOUT config-
ured as lock detect and polled by the port input).
When operating in the mode described, the maximum SCLOCK
rate of the ADuC812 is 4 MHz. This means that the maximum
rate at which the output frequency can be changed will be 166 kHz.
SCLOCK
MOSI
ADuC812
I/O PORTS
SCLK
SDATA
LE ADF4106
CE
MUXOUT
(LOCK DETECT)
Figure 8. ADuC812 to ADF4106 Interface
ADSP-2181 Interface
Figure 9 shows the interface between the ADF4106 and the
ADSP-21xx Digital Signal Processor. The ADF4106 needs a
24-bit serial word for each latch write. The easiest way to
accomplish this using the ADSP-21xx family is to use the
Autobuffered Transmit Mode of operation with Alternate Framing.
This provides a means for transmitting an entire block of serial
data before an interrupt is generated. Set up the word length for
8 bits and use three memory locations for each 24-bit word. To
program each 24-bit latch, store the three 8-bit bytes, enable the
Autobuffered mode and then write to the transmit register of the
DSP. This last operation initiates the autobuffer transfer.
SCLOCK
MOSI
ADSP-21xx TFS
I/O FLAGS
SCLK
SDATA
LE ADF4106
CE
MUXOUT
(LOCK DETECT)
Figure 9. ADSP-21xx to ADF4106 Interface
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