Kontron COMe Starterkit Eval T2 - Manual (Page 211)

Appendix B: Sourcecode for Port 80 Decoder
LPC_State <= IDLE; -- abort cycle, bad frame
-- or address mismatch
else
-- Write address valid. Subsequent Data displays.
LPC_State <= WDATN0; -- Next state will get
-- first data nibble
end if;
when WDATN0 => -- Data LSN (Least Significant Nibble)is
-- sent first
W_Data(3 downto 0) <= lad_rin; -- latch data (LSN)
if (lframe_nreg = '1') then
LPC_State <= WDATN1; ¬¬¬-- Next state gets
-- 2nd data nibble
else
LPC_State <= IDLE;
end if;
when WDATN1 => -- Data MSN (Most Significant Nibble)
W_Data(7 downto 4) <= lad_rin; -- latch data (MSN)
if (lframe_nreg = '1') then
LPC_State <= WHTAR0;
else
LPC_State <= IDLE;
end if;
when WHTAR0 => -- Write Data Turn Around Cycle 0
if (lframe_nreg = '1') and (lad_rin = "1111") then
LPC_State <= WHTAR1;
else
LPC_State <= IDLE;
end if;
when WHTAR1 => -- Write Data Turn Around Cycle 1
if (lframe_nreg = '1') then
LPC_State <= WSYNC;
else
LPC_State <= IDLE;
end if;
when WSYNC => -- Write Data Sync Cycle
-- Note: No device to respond with a synch at I\O addr
-- 080h. Therefore bus should time out and abort.
-- State ==> to IDLE
if (lframe_nreg = '1') then
LPC_State <= WPTAR;
else
LPC_State <= IDLE;
end if;
when WPTAR => -- Write Data Final Turn Around Cycle
-- (not needed -- see WSYNC)
LPC_State <= IDLE; -- I/O write cycle end
when others =>
LPC_State <= IDLE; -- all other cases
end case;
end if;
end if;
end process;
P_sseg_decode: process(lclk) -- decode section for 7 seg displays
begin
if (lclk'event and lclk='1') then
case W_Data(7 downto 4) is -- Most sig digit for display
when "0000" => seven_seg_H <= "00000011"; -- Hex 03 displays a 0
when "0001" => seven_seg_H <= "10011111";-- Hex 9f displays a 1
when "0010" => seven_seg_H <= "00100101"; -- Hex 25 displays a 2
when "0011" => seven_seg_H <= "00001101"; -- Hex 0d displays a 3
when "0100" => seven_seg_H <= "10011001"; -- Hex 99 displays a 4
when "0101" => seven_seg_H <= "01001001"; -- Hex 49 displays a 5
when "0110" => seven_seg_H <= "01000001"; -- Hex 41 displays a 6
PICMG ® COM Express ® Carrier Board Design Guide Rev. 2.0 / December 6, 2013
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