내가 어떤의 UART의 각 인스턴스에 대해 래티스 다이아몬드에서 이러한 경고를 가지고 왜 볼 수 없습니다 (현재 11)경고 "무부하"하지만
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_14' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_0_COUT1_9_14' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_12' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_10' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_8' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_6' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_4' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_2' has no load
WARNING - ngdbuild: logical net 'UartGenerator_0_Uart_i/Uart/rxCounter_cry_0' has no load
VHDL 코드는
entity UART is
generic (
dividerCounterBits: integer := 16
);
port (
Clk : in std_logic; -- Clock signal
Reset : in std_logic; -- Reset input
ClockDivider: in std_logic_vector(15 downto 0);
ParityMode : in std_logic_vector(1 downto 0); -- b00=No, b01=Even, b10=Odd, b11=UserBit
[...]
architecture Behaviour of UART is
constant oversampleExponent : integer := 4;
subtype TxCounterType is integer range 0 to (2**(dividerCounterBits+oversampleExponent))-1;
subtype RxCounterType is integer range 0 to (2**dividerCounterBits)-1;
signal rxCounter: RxCounterType;
signal txCounter: TxCounterType;
signal rxClockEn: std_logic; -- clock enable signal for receiver
signal txClockEn: std_logic; -- clock enable signal for transmitter
begin
rxClockdivider:process (Clk, Reset)
begin
if Reset='1' then
rxCounter <= 0;
rxClockEn <= '0';
elsif Rising_Edge(Clk) then
-- RX counter (oversampled)
if rxCounter = 0 then
rxClockEn <= '1';
rxCounter <= to_integer(unsigned(ClockDivider));
else
rxClockEn <= '0';
rxCounter <= rxCounter - 1;
end if;
end if;
end process;
txClockDivider: process (Clk, Reset)
[...]
rx: entity work.RxUnit
generic map (oversampleFactor=>2**oversampleExponent)
port map (Clk=>Clk, Reset=>Reset, ClockEnable=>rxClockEn, ParityMode=>ParityMode,
ReadA=>ReadA, DataO=>DataO, RxD=>RxD, RxAv=>RxAv, ParityBit=>ParityBit,
debugout=>debugout
);
end Behaviour;
이 내가이
-- UARTs
UartGenerator: For i IN 0 to uarts-1 generate
begin
Uart_i : entity work.UartBusInterface
port map (Clk=>r_qclk, Reset=>r_reset,
cs=>uartChipSelect(i), nWriteStrobe=>wr_strobe, nReadStrobe=>rd_strobe,
address=>AdrBus(1 downto 0), Databus=>DataBus,
TxD=>TxD_PAD_O(i), RxD=>RxD_PAD_I(i),
txInterrupt=>TxIRQ(i), rxInterrupt=>RxIRQ(i), debugout=>rxdebug(i));
uartChipSelect(i) <= '1' when to_integer(unsigned(adrbus(5 downto 2)))=i+4 and r_cs0='0' else '0';
end generate;
을 사용 나는 그것을 syntesis 수 있고, UART를 작동하지만, 왜 그들에게 모든 (현재 11 개의 UART)을 생성하기 위해 하나의 UART이다 경고 받았어?
IMHO rxCounter는 각 단일 값을 사용해야하지만 두 번째 비트가 각각 "no load"이라는 경고를 생성하는 이유는 무엇입니까?
나는이 그물이 사용되지 않고 제거 될 것이라는 것을 의미하는 어딘가에서 읽었다.
0에서 2^n-1까지 계산하려면 n 비트 이상 필요합니다.
코드를 시뮬레이트 해 보셨습니까? – sonicwave
@sonicwave - 아니요,하지만 syntesis가있을 수 있으며 예상대로 작동합니다. – jeb