--[[
Eugeniy Mikhailov
1 June 2021
 (copied over from past work)]]

-- there are 8 registers to track for lmx2487
-- labeled R0, R1, ..., R7 in the manual
lmx2487_registers   = {0, 0, 0, 0, 0, 0, 0, 0}
-- if a register needs update set to true, updater script will resend this register
lmx2487_need_update = {true, true, true, true, true, true, true, true}

function set_lmx2487register(value, register)
	-- register labeled 0, 1, 2, ..., 7
	if (lmx2487_registers[register+1] ~= value) then
		-- this is new value and thus needs to be updated in hardware
		lmx2487_registers[register+1] = value
		lmx2487_need_update[register+1] = true
	end
end

function get_lmx2487register(register)
	-- register labeled 0, 1, 2, ..., 7
	local value = (lmx2487_registers[register+1])
	return value
end

function send_register_lmx2487( register)
	if ( lmx2487_need_update[register +1] ) then
		if DEBUG then
			print("sending register " .. register .. " with value " .. get_lmx2487register( register ) )
		end
		-- do hardware talking
		microwire_send_data( get_lmx2487register( register ) )
		lmx2487_need_update[register+1]=false
	end
end

function update_lmx2487state()
	for register=7,0,-1 do
		-- going over registers
		-- manual suggest to send R0 as last one
		send_register_lmx2487( register )
	end
end


function set_lmx2487_board_to_default_state()
	-- this defaults are historic and borrowed from lmx2487lib.tcl
	-- defaults (set RF freq to 6.83468635e9 GHz and lock it to 10MHz oscillator)
	lmx2487_need_update = {true, true, true, true, true, true, true, true}
	set_lmx2487register(11197502  , 0)
	set_lmx2487register(4352515   , 1)
	set_lmx2487register(8560613   , 2)
	set_lmx2487register(15925287  , 3)
	set_lmx2487register(10618633  , 4)
	set_lmx2487register(393579    , 5)
	set_lmx2487register(8126541   , 6)
	set_lmx2487register(10639     , 7)

	update_lmx2487state()
end

function freq2regestersValues(freq)

  local F_COMP = 5000000 -- magic number
  local N = freq / F_COMP

  local RF_N = math.floor(N)

  local frac = math.abs(N - RF_N)

  local RF_FD = 4000000 --magic number
  local RF_FN = math.floor( (frac * RF_FD) + 0.5)
   
  return freq, RF_N, RF_FN, RF_FD
end
-- test freq2regestersValues
fIn = 6.834e9
freq, RF_N, RF_FN, RF_FD = freq2regestersValues(fIn)
if freq ~= fIn and RF_N ~= 1366 and RF_FN ~= 3200000 and 4000000 then
	print("ERROR in freq2regestersValues")
end
fIn=nil
freq=nil
RF_N=nil
RF_FN=nil
RF_FD=nil
-- end of freq2regestersValues test


-- bits in mask counted starting from position 1,
-- i.e. 1 sets bit in 1st pos, 2 sets bit in 2nd pos
mask_bits14to24=bit.lshift( bit.bit(11)-1, 13)
mask_bits2to13=bit.lshift( bit.bit(12)-1, 1)
mask_bits5to16=bit.lshift( bit.bit(12)-1, 4)
mask_bits5to14=bit.lshift( bit.bit(10)-1, 4)
mask_bits15to24=bit.lshift( bit.bit(10)-1, 14)
mask_bits5to24=bit.bor(mask_bits5to14, mask_bits15to24)
mask_low12bits = bit.bit(12)-1
mask_bits13andAbove = bit.bnot(mask_low12bits)

function FreqToSettings(freq)
    local freq, RF_N, RF_FN, RF_FD = freq2regestersValues(freq)
    R0_new=get_lmx2487register(0)
    R1_new=get_lmx2487register(1)
    R5_new=get_lmx2487register(5)

    -- This code is extremely convoluted, refer to the lmx2487 manual
    -- to see what bits are used in what place in a register.
    -- But I show in comments obsolete but human readable notation:
    -- tableReplace( Rn, bitSlice(..), stPos, endPos)

    -- settings["R0"]=tableReplace(settings["R0"], bRF_N, 14, 24)
    bitsRF_N = bit.lshift(RF_N, 13)
    R0_new = bit.band(R0_new, bit.bnot(mask_bits14to24))
    R0_new = bit.bor(R0_new, bitsRF_N)

    -- settings["R0"]=tableReplace(settings["R0"], bitSlice(bRF_FN, 1, 12), 2, 13)
    bitsRF_FN_low = bit.band( RF_FN, mask_low12bits)
    R0_new = bit.band(R0_new, bit.bnot(mask_bits2to13))
    R0_new = bit.bor(R0_new, bit.lshift(bitsRF_FN_low,1))

    -- settings["R1"]=tableReplace(settings["R1"], bitSlice(bRF_FD, 1, 12), 5, 16)
    bitsRF_FD_low = bit.band( RF_FD, mask_low12bits)
    R1_new = bit.band(R1_new, bit.bnot(mask_bits5to16))
    R1_new = bit.bor(R1_new, bit.lshift(bitsRF_FD_low,4))

    -- settings["R5"]=tableReplace(settings["R5"], bitSlice(bRF_FN, 13, 22), 5, 14)
    -- settings["R5"]=tableReplace(settings["R5"], bitSlice(bRF_FD, 13, 22), 15, 24)
    RF_FN_above_12 = bit.band( RF_FN, mask_bits13andAbove)
    RF_FN_part = bit.rshift(RF_FN_above_12, 12)
    RF_FD_above_12 = bit.band( RF_FD, mask_bits13andAbove)
    RF_FD_above_12 = bit.rshift( RF_FD_above_12, 2)
    new_bits = bit.bor(RF_FN_part, RF_FD_above_12)
    R5_new = bit.band(R5_new, bit.bnot(mask_bits5to24))
    R5_new = bit.bor(R5_new, bit.lshift(new_bits,4))

    set_lmx2487register(R0_new, 0)
    set_lmx2487register(R1_new, 1)
    set_lmx2487register(R5_new, 5)
end

-- test setFreq
set_lmx2487_board_to_default_state()
FreqToSettings(6.834e9)
if 
	get_lmx2487register(0) ~= 11192320 
	and get_lmx2487register(1) ~= 4362243
	and get_lmx2487register(2) ~= 8560613 -- should not change
	and get_lmx2487register(5) ~= 16003291
then
	print("ERROR in FreqToSettings: registers do not match")
end
FreqToSettings(6.8204e9)
if 
	get_lmx2487register(0) ~= 11174912 
	and get_lmx2487register(1) ~= 4362243 -- should not change
	and get_lmx2487register(2) ~= 8560613 -- should not change
	and get_lmx2487register(5) ~= 15992043
then
	print("ERROR in FreqToSettings: registers do not match")
end
FreqToSettings(6.8346e9)
if 
	get_lmx2487register(0) ~= 11193856 
	and get_lmx2487register(1) ~= 4362243 -- should not change
	and get_lmx2487register(2) ~= 8560613 -- should not change
	and get_lmx2487register(5) ~= 16005163
then
	print("ERROR in FreqToSettings: registers do not match")
end

function setFreq(freq)
	FreqToSettings(freq)
	update_lmx2487state() 
end