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[/] [open8_urisc/] [trunk/] [VHDL/] [o8_rtc.vhd] - Rev 223

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223 Added an OPEN8_BUS_TYPE record to simplify connection to Open8 modules. The CPU now passes and Open8_Bus out, which supplies the bus address, write enable, write data, and read enable. Read data and interrupts are still handled as separate signals, since they are muxed/connected at the next level up. jshamlet 1700d 13h /open8_urisc/trunk/VHDL/o8_rtc.vhd
217 Broke out the vdsm8 as a separate entity, since it is used in several places,
Even MORE code cleanup.
jshamlet 1701d 14h /open8_urisc/trunk/VHDL/o8_rtc.vhd
213 Code and comment cleanup jshamlet 1705d 15h /open8_urisc/trunk/VHDL/o8_rtc.vhd
211 Ok, this time with feeling. Timer should now properly reset on interval update. jshamlet 1706d 19h /open8_urisc/trunk/VHDL/o8_rtc.vhd
210 Modified the timers to reset on new interval write. This avoids an issue in the original design where the timer had to reach zero before updating, potentially causing unwanted interrupts.
Also added a flag to the CPU to allow interrupts to be processed sequentially based on the state of the I bit. This one is set to false by default, as it is a significant change in interrupt behavior. Long, and reentrant, ISRs can clear the I bit prematurely to allow themselves to be interrupted.
Lastly, added the I bit to the exported flags for possible use in memory protection schemes.
jshamlet 1706d 21h /open8_urisc/trunk/VHDL/o8_rtc.vhd
209 Fixed an issue in the PIT timer that caused an immediate interrupt on interval write,
Fixed an issue in the epoch timer that resulted in a spurious interrupt due to extra LSB's being set by default in the set point register,
While cleaning elsewhere, founding a spacing issue in the CPU HDL,
Added a 4k ROM and MW core.
jshamlet 1707d 10h /open8_urisc/trunk/VHDL/o8_rtc.vhd
194 Cleaned up licensing sections jshamlet 1715d 16h /open8_urisc/trunk/VHDL/o8_rtc.vhd
191 Cleaned up comments, added back the OPEN8_NULLBUS constant, and added some new modules for ADCs and LCD displays.
Also made the button input module more configurable by moving the debounce code to a separate entity and using generics to instantiate it.
jshamlet 1715d 17h /open8_urisc/trunk/VHDL/o8_rtc.vhd
190 Fixed a bug in CPU where RTI/RTS wasn't idling the instruction cache, causing intermittent failures where RTI would execute as RTS, corrupting the stack;
Fixed a bug in the real-time clock where the uSec tick generator would stop if the PIT timer value was left/set to 0x00.
jshamlet 1727d 14h /open8_urisc/trunk/VHDL/o8_rtc.vhd
189 Merged changes from private repository,
added ceil_log2 function to Open8_pkg, since it is used to calculate RAM vectors,
cleaned up comments and removed local copies of the ceil_log2 function from peripherals.
jshamlet 1728d 15h /open8_urisc/trunk/VHDL/o8_rtc.vhd
177 Fixed comments in RTC module jshamlet 3060d 17h /open8_urisc/trunk/VHDL/o8_rtc.vhd
176 Fixed documentation errors,
Modified uSec_Tick such that it is always generated regardless of the interval.
jshamlet 3065d 15h /open8_urisc/trunk/VHDL/o8_rtc.vhd
172 General code cleanup jshamlet 3260d 15h /open8_urisc/trunk/VHDL/o8_rtc.vhd
168 Simplified write data path logic,
Converted RTC to packed BCD,
Corrected several bugs in real time clock component,
jshamlet 4094d 12h /open8_urisc/trunk/VHDL/o8_rtc.vhd
167 Updated CPU model; Pipelined ALU control signals to improve fMAX, corrected issue with interrupt controller priority not being obeyed, fixed bug in auto-indexing instructions where the upper register wasn't being properly incremented, cleaned up code to make the processor model easier to follow.
Added several useful modules that use the Open8 bus.
jshamlet 4102d 10h /open8_urisc/trunk/VHDL/o8_rtc.vhd

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