Other Parts Discussed in Thread: TICSPRO-SW
Hello,
I am having a problem with the LMX2582 locking after I re-write all the registers. I found issue after noticing the synthesizer was not locked after a power cycle. I tried to send all the registers again and it locked. I added the functionality to my code to re-send the all the initialize commands when I command it to and found that about 50% of the time the synthesizer would no lock. I read back the contents of all the registers and verified that they contained what I had written.
The OSC input is coming from a single-ended 10MHz CMOS output through an RC (1K, 18pF) filter so the waveform being fed to the OSCinP pin is a 0-1.5v signal while the OSCinN pin is tied to ground through a 1K resistor to match impedances. Both inputs also have an 0.01uF AC-coupling capacitor.
I cannot think of anything else to try and was hoping for some help in finding what I am doing wrong. Please see below the values for the registers I am writing to the synthesizer, my code sends the address and data from the bottom of the list (index 43) to the top (index 0).
// LMX2582 Synthesizer Defaults
SYN_REG code synth_inits[REG_CNT] = {
{ 0, 0x221C},
{ 1, 0x0808},
{ 2, 0x0500},
{ 4, 0x1943},
{ 7, 0x28B2},
{ 8, 0x1084},
{ 9, 0x0302},
{10, 0x10DB},
{11, 0x0018},
{12, 0x7001},
{13, 0x4000},
{14, 0x0FFF},
{19, 0x0965},
{20, 0x012C},
{22, 0x2300},
{23, 0x8842},
{24, 0x0509},
{25, 0x0000},
{28, 0x2924},
{29, 0x0084},
{30, 0x0034},
{31, 0x0401},
{32, 0x210A},
{33, 0x2A0A},
{34, 0xC3EA},
{35, 0x089B}, // set for /12
{36, 0x0421},
{37, 0x5000},
{38, 0x00F0}, // N Divider = 120
{39, 0x8204},
{40, 0x03F9},
{41, 0x40AB}, // PLL Den = 66,666,667 => 0.05 Hz resolution
{42, 0x0000},
{43, 0x0000},
{44, 0x0262}, // just a default, but ...
{45, 0x5A00}, // PLL Num = 40,000,000 => 402 MHz
{46, 0x00A3},
{47, 0x00C0},
{48, 0x03FC},
{59, 0x0000},
{61, 0x0001},
{62, 0x0000},
{64, 0x03AF},
{ 0, 0x2206},
};
