1 -- A JTAG complient tap controller implementation
2 -- This is implemented based on the IEEE 1149.1 standard
5 use ieee.std_logic_1164.ALL;
9 entity c4m_jtag_tap_controller is
11 DEBUG: boolean := false;
13 IR_WIDTH: integer := 2;
16 MANUFACTURER: std_logic_vector(10 downto 0) := "10001111111";
17 PART_NUMBER: std_logic_vector(15 downto 0) := "0000000000000001";
18 VERSION: std_logic_vector(3 downto 0) := "0000"
28 -- The Instruction Register
29 IR: out std_logic_vector(IR_WIDTH-1 downto 0);
31 -- The FSM state indicators
33 CAPTURE: out std_logic;
35 UPDATE: out std_logic;
37 -- The I/O access ports
38 CORE_IN: out std_logic_vector(IOS-1 downto 0);
39 CORE_EN: in std_logic_vector(IOS-1 downto 0);
40 CORE_OUT: in std_logic_vector(IOS-1 downto 0);
42 -- The pad connections
43 PAD_IN: in std_logic_vector(IOS-1 downto 0);
44 PAD_EN: out std_logic_vector(IOS-1 downto 0);
45 PAD_OUT: out std_logic_vector(IOS-1 downto 0)
47 end c4m_jtag_tap_controller;
49 architecture rtl of c4m_jtag_tap_controller is
50 signal S_RESET: std_logic;
51 signal S_ISIR: std_logic;
52 signal S_ISDR: std_logic;
53 signal S_CAPTURE: std_logic;
54 signal S_SHIFT: std_logic;
55 signal S_UPDATE: std_logic;
56 signal S_IR: std_logic_vector(IR_WIDTH-1 downto 0);
58 signal IR_TDO: std_logic;
59 signal IR_TDO_EN: std_logic;
60 signal ID_TDO: std_logic;
61 signal ID_TDO_EN: std_logic;
62 signal IO_TDO: std_logic;
63 signal IO_TDO_EN: std_logic;
67 CAPTURE <= S_CAPTURE and S_ISDR;
68 SHIFT <= S_SHIFT and S_ISDR;
69 UPDATE <= S_UPDATE and S_ISDR;
85 -- The instruction register
86 IRBLOCK: c4m_jtag_irblock
97 CAPTURE => S_CAPTURE and S_ISIR,
98 SHIFT => S_SHIFT and S_ISIR,
99 UPDATE => S_UPDATE and S_ISIR
103 IDBLOCK: c4m_jtag_idblock
105 IR_WIDTH => IR_WIDTH,
106 PART_NUMBER => PART_NUMBER,
107 MANUFACTURER => MANUFACTURER,
116 CAPTURE => S_CAPTURE and S_ISDR,
117 SHIFT => S_SHIFT and S_ISDR,
118 UPDATE => S_UPDATE and S_ISDR
122 IOBLOCK: c4m_jtag_ioblock
124 IR_WIDTH => IR_WIDTH,
133 CAPTURE => S_CAPTURE and S_ISDR,
134 SHIFT => S_SHIFT and S_ISDR,
135 UPDATE => S_UPDATE and S_ISDR,
136 CORE_OUT => CORE_OUT,
144 TDO <= IR_TDO when IR_TDO_EN = '1' else
145 ID_TDO when ID_TDO_EN = '1' else
146 IO_TDO when IO_TDO_EN = '1' else
149 CHECK_EN: if DEBUG generate
150 signal EN: std_logic_vector(2 downto 0) := "000";
152 EN <= IR_TDO_EN & ID_TDO_EN & IO_TDO_EN;
153 assert EN = "000" or EN = "100" or EN = "010" or EN = "001"
154 report "TDO conflict in c4m_jtag_tap_controller"
156 end generate CHECK_EN;