First VHDL-attempts to remove DC from BladeRF-outputs
Well,
subject says it all.
Last few
weeks I did study VHDL a lot and came up with the following change of the
lms6002d.vhdl piece:
library ieee ;
use ieee.std_logic_1164.all ;
use ieee.numeric_std.all ;
-- modified to remove
DC-component
-- March-2014 KdG
entity lms6002d is
port (
-- RX Controls
rx_clock :
in std_logic ;
rx_reset :
in std_logic ;
rx_enable :
in std_logic ;
-- RX Interface with LMS6002D
rx_lms_data :
in signed(11 downto 0) ;
rx_lms_iq_sel :
in std_logic ;
rx_lms_enable :
buffer std_logic ;
-- RX Sample Interface
rx_sample_i :
buffer signed(11 downto 0) ;
rx_sample_q :
buffer signed(11 downto 0) ;
rx_sample_valid :
buffer std_logic ;
-- TX Controls
tx_clock :
in std_logic ;
tx_reset :
in std_logic ;
tx_enable :
in std_logic ;
-- TX Sample Interface
tx_sample_i :
in signed(11 downto 0) ;
tx_sample_q :
in signed(11 downto 0) ;
tx_sample_valid :
in std_logic ;
-- TX Interface to the LMS6002D
tx_lms_data :
buffer signed(11 downto 0) ;
tx_lms_iq_sel :
buffer std_logic ;
tx_lms_enable :
buffer std_logic
) ;
end entity ;
architecture arch of
lms6002d is
signal rx_average_i,
rx_average_q : signed(11 downto 0);
signal accum_i :
signed(18 downto 0) ;
signal accum_q :
signed(18 downto 0) ;
begin
-------------
-- Receive --
-------------
rx_sample : process(rx_clock, rx_reset)
begin
if( rx_reset = '1' ) then
rx_sample_i <= (others =>'0')
;
rx_sample_q <= (others =>'0')
;
rx_average_i <= (others
=> '0'); -- KdG
rx_average_q <= (others
=> '0'); -- KdG
rx_sample_valid <= '0' ;
rx_lms_enable <= '0' ;
elsif( rising_edge( rx_clock ) ) then
if( rx_lms_iq_sel = '0' ) then
rx_lms_enable <= rx_enable ;
end if ;
rx_sample_valid <= '0' ;
if( rx_lms_enable = '1' ) then
if(rx_lms_iq_sel = '1' ) then
-- rx_sample_i <=
rx_lms_data;
rx_sample_i <= rx_lms_data -
rx_average_i; -- KdG
else
-- rx_sample_q <=
rx_lms_data;
rx_sample_q <= rx_lms_data - rx_average_q
; -- KdG
rx_sample_valid <= '1' ;
end if ;
end if ;
end if ;
end process ;
--------------
-- Transmit --
--------------
tx_sample : process(tx_clock, tx_reset)
variable tx_q_reg :
signed(11 downto 0) ;
begin
if( tx_reset = '1' ) then
tx_lms_data <= (others =>'0')
;
tx_lms_iq_sel <= '0' ;
tx_lms_enable <= '0' ;
tx_q_reg := (others =>'0') ;
elsif( rising_edge( tx_clock ) ) then
if( tx_lms_iq_sel = '0' ) then
tx_lms_enable <= tx_enable ;
end if ;
if( tx_sample_valid = '1' ) then
tx_lms_data <= tx_sample_i ;
tx_q_reg := tx_sample_q ;
tx_lms_iq_sel <= '0' ;
elsif( tx_lms_enable = '1' ) then
tx_lms_data <= tx_q_reg ;
tx_lms_iq_sel <= '1' ;
else
tx_lms_data <= (others
=>'0') ;
tx_lms_iq_sel <= '0' ;
end if ;
end if ;
end process ;
average: process(rx_sample_valid)
variable count : integer ;
begin
if( rising_edge( rx_sample_valid ) ) then
if(rx_lms_iq_sel = '1' ) then
accum_i <= accum_i + rx_lms_data;
else
accum_q <= accum_q + rx_lms_data;
end if;
count := count + 1;
if ( count > 128 ) then
count := 0;
rx_average_i(11 downto 0) <= accum_i (18
downto 7);
rx_average_q(11 downto 0) <= accum_q (18
downto 7);
accum_i <= (others =>'0') ;
accum_q <= (others =>'0') ;
end if;
end if;
end
process average;
end architecture ;
I
declared some signals and calculate the average in a separate process.
I get
some errors from Quartus:
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[11]" at lms6002d.vhd(114)
Error
(10029): Constant driver at lms6002d.vhd(53)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[10]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[9]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[8]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[7]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[6]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[5]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[4]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[3]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[2]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[1]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_i[0]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[11]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[10]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[9]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[8]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[7]" at lms6002d.vhd(114)
Error
(10028): Can't resolve multiple constant drivers for net
"rx_average_q[6]" at lms6002d.vhd(114)
Thusfar
I do not understand this error-messages.
Because
it was a long time ago already that I posted something on my blog, this is a
kind of “I am still alive message”.
I will
dig into this problem, but I would LOVE to get some hints from VHDL-gurus!
Next time I hope to come up with a working VHDl-solution.
