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Rev Log message Author Age Path
227 Added a demonstration Open8_cfg.vhd file, which is used to configure the system constants. It also provides a function that makes it easy to merge read buses. jshamlet 1701d 07h /
226 Forgot the updated package file... jshamlet 1701d 11h /
225 Added Halt_Ack to go with Halt_Req. jshamlet 1701d 11h /
224 Finished new Open8 bus record, which now includes the clock, reset and a microsecond tick. The CPU now accepts a clock and pll_locked signal, which it uses to generate the system reset in the bus record. It also contains a simple microsecond counter to feed the usec_tick in the record. This logic was removed from the real time clock and system timer entities, which now use the global version. Bus connections should be dramatically simplified, as only the read logic and interrupts are still run as separate signals. jshamlet 1701d 13h /
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 1702d 06h /
222 Created a modified version of the epoch timer with a 32-bit, 1-uS resolution timer/comparator. jshamlet 1702d 11h /
221 o8_vdsm8.vhd now has a default value assigned at compile time, o8_register.vhd was cleaned up some more. jshamlet 1703d 06h /
220 More revision sections added jshamlet 1703d 06h /
219 Added revision block and corrected creation date. jshamlet 1703d 06h /
218 Revision sections added,
vdsm8.vhd added.
jshamlet 1703d 07h /
217 Broke out the vdsm8 as a separate entity, since it is used in several places,
Even MORE code cleanup.
jshamlet 1703d 07h /
216 Fixed missing parenthesis jshamlet 1703d 09h /
215 More code cleanup jshamlet 1703d 09h /
214 Initial add of some older code jshamlet 1707d 07h /
213 Code and comment cleanup jshamlet 1707d 08h /
212 Fixed issue with rewritten epoch timer not clearing alarm on set point write. jshamlet 1707d 14h /
211 Ok, this time with feeling. Timer should now properly reset on interval update. jshamlet 1708d 11h /
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 1708d 14h /
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 1709d 03h /
208 Removed unnecessary package references jshamlet 1709d 12h /

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