Timer Unit
- Operates as a One-shot counter with single value
- Count uS, mSec or secs (allows for different resolutions)
- Write to count value starts timer
- Poll timer status
Address Value Read/Write Data
0 uSec Count Write 0-255 uS count - write starts timer
1 mSec Count Write 0-255 mS count - write starts timer
2 Sec Count Write 0-255 sec count - write starts timer
3 Not Used Write Not used
0-3 Status Read 1 = Count In progresss
0 = Done
Timer Unit Subroutines
- Pass number of secs to wait in Reg1
WAITSECS IOW 0X01 0X06 STORE REG0 TO START TIMER
WTLPSEC IOR 0X01 0X04 READ TIMER
ARI 0X01 0X01 CHECK BUSY
BNZ WTLPSEC
RTS
Entity
-- ____________________________________________________________________________________
-- Timer Unit
w_timerAdr <= '1' when (w_peripAddr(7 downto 2) = "000010") else '0';
timerUnit : entity work.TimerUnit
port map
(
-- Clock and Reset
i_clk => i_clock,
i_n_reset => w_resetClean_n,
-- The key and LED on the FPGA card
i_timerSel => w_timerAdr,
i_writeStrobe => w_peripWr,
i_regSel => w_peripAddr(1 downto 0),
i_dataIn => w_peripDataFromCPU,
o_dataOut => w_timerOut
);
Resources (EP4CE15)
- Logic Cells: 89
- Registers: 49
- Memory Bits: 0
