Question
I am working on AD6636 chip (Programing the chip thro SPI interface from FPGA ) .This chip does not respond to "Hop soft Sync".But it is working for"Start Soft Sync".As we are working on GSM System ,we need to change the freqency(NCO) frequently on live using "Hop soft Sync" only.I amprogramming the chip as below to change freq of all 6 channels as per the datasheet.Pls help me to correct the issue.
0x03013F - channel enable reg- CH0 to CH5 are enabled.
0x020109 - Channel I/O Access cntrl reg -only CH0 &CH3 are accessed.0x7304& CW(32bit) - NCO for CH0 & CH3
0x020112 - Channel I/O Access cntrl reg -only CH1 &CH4 are accessed.0x7304& CW(32bit) - NCO for CH1 & CH4
0x020124 - Channel I/O Access cntrl reg -only CH2 &CH5 are accessed.0x7304& CW(32bit) - NCO for CH2 & CH5
0x02013F - CH0 - CH5 are accessed0x6D020001 -NCO Freq hold-off cntr(0x0001)
0x050100 -Soft Sync Confgn Reg (0x00)
0x0501BF -Soft Hop Sync is enabled for CH0-CH5
0x0501BF -Soft Hop Sync is enabled for CH0-CH5 (Repeated for SPI programing)
Programmed from top to bottom serially with MSB first.Each row contains Start add+(R/W~+Cont)+Data bytes
Answer
Please refer to the following suggestion.
I have attached a very simple procedure that I have tried previously in my lab that just hops a single channel.