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ADF4350 SPI programming through LPC2148

Question asked by tejasmit on Dec 27, 2011
Latest reply on Jan 6, 2012 by tejasmit

Hi,

i want to sweep in frequency range from 2.2 GHz- 2.5GHz in steps of 500 KHz

i'm using the evaluation board ADF4350EB1Z

initially i tried generating a single frequecy of 2.4 GHz

i could succesfully generate it using the software provided by analog devices but when i use the SAME REGISTER VALUES and send them from my controller i dont get any output and there is no locking too

i send the registers in the sequence r5,r4,r3,r2,r1,r0

i sent a high pulse on le line after each set of 32 bits were sent i.e i made le high and then low again to get a pulse of approx 100ns width

i m using spi at 4MHz frequency

register values are-

r5-0x00580005

r4-0x008c803c

r3-0x000004b3

r2-0x00004ec2

r1-0x08008191

r0-0x00300008

this sequence was ideally supposed to generate 2400.5MHz but i am not getting any output at all

do i need to take care of any timing considerations or anything else that is causing my code to not work properly

is there any major mistake that i hav done

i am using cpha=0

i am using lpc2148 controller

any help will b great!!

thanks a lot!!

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