uart_package.vhd

此为FPGA上的一个串口通信程序

-- 库声明
library IEEE;
use IEEE.STD_LOGIC_1164.all; 

-- 包声明
PACKAGE UART_PACKAGE IS	 
	
-- 信号监测器状态
type dt_state is 
(
dt_unlock,			-- 未锁定状态
dt_lock 			-- 锁定状态
);	 

-- UART状态
type UART_STATE is
( 
UART_IDLE,
UART_LOAD,
UART_SEND,	
UART_END_SEND,
UART_RECV,
UART_END_RECV
);

-- 计数器计数范围
type BD_COUNT is range 65535 downto 0;

-- 9600波特率对应参数
constant BD9600_FPC : BD_COUNT := 1152;
constant BD9600_HPC : BD_COUNT := 576;

-- 奇偶校验规则定义
type PARITY is
(
NONE,		-- 无奇偶校验
ODD,		-- 奇校验
EVEN		-- 偶校验
);

-- 函数声明
function MultiXOR(
	din : in std_logic_vector )
  	return std_logic;

END UART_PACKAGE;

-- 包体
PACKAGE BODY UART_PACKAGE IS

-- 函数实现
function MultiXOR(
	din : in std_logic_vector )
  	return std_logic is
	variable check : std_logic;
begin
	check := din(din'LOW);
	for i in 1 to (din'HIGH) loop
		check := check xor din(i);
	end loop;
		
	return check;
end MultiXOR;

END UART_PACKAGE;