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Don't use tri-state logic for TDO; introduce TDO_EN signal to indicate when TDO is...
[c4m-jtag.git]
/
rtl
/
vhdl
/
c4m_jtag_idblock.vhdl
diff --git
a/rtl/vhdl/c4m_jtag_idblock.vhdl
b/rtl/vhdl/c4m_jtag_idblock.vhdl
index d4353c1b025dde0435262be9297753f539517587..4c06befd405abc145ed49f45cc87ac59b6c61366 100644
(file)
--- a/
rtl/vhdl/c4m_jtag_idblock.vhdl
+++ b/
rtl/vhdl/c4m_jtag_idblock.vhdl
@@
-18,6
+18,7
@@
entity c4m_jtag_idblock is
TCK: in std_logic;
TDI: in std_logic;
TDO: out std_logic;
TCK: in std_logic;
TDI: in std_logic;
TDO: out std_logic;
+ TDO_EN: out std_logic := '0';
-- JTAG state
STATE: in TAPSTATE_TYPE;
-- JTAG state
STATE: in TAPSTATE_TYPE;
@@
-65,5
+66,7
@@
begin
EN_TDO <= STATE = Shift and DRSTATE = '1' and (IR = CMD_IDCODE or IR = CMD_BYPASS);
TDO <= SR_ID(0) when EN_TDO else
EN_TDO <= STATE = Shift and DRSTATE = '1' and (IR = CMD_IDCODE or IR = CMD_BYPASS);
TDO <= SR_ID(0) when EN_TDO else
- 'Z';
+ '0';
+ TDO_EN <= '1' when EN_TDO else
+ '0';
end rtl;
end rtl;