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275 Fixed a minor comment error. jshamlet 1327d 08h /open8_urisc/
274 Updated comments with more corrections jshamlet 1327d 15h /open8_urisc/
273 Updated comments with corrections jshamlet 1327d 17h /open8_urisc/
272 Updated the HTML documentation to reflect the removed generic. jshamlet 1337d 16h /open8_urisc/
271 Removed deleted generic define. jshamlet 1337d 16h /open8_urisc/
270 Moved CPU internal constants to o8_cpu.vhd and replace the generic that set the RSP direction flag with a constant instead. This removes the need to expose internal architectural flags externally.

Also added a hard-coded version register that takes a major and minor value as bytes using generics. This is a read-only register to the CPU.
jshamlet 1337d 16h /open8_urisc/
269 Modified the write data path to use separate enumerated states rather than reuse the .reg field to improve performance. jshamlet 1340d 06h /open8_urisc/
268 Added a 16-input external interrupt manager and dedicated SPI tx-only transmitter (for use with DACs, etc.). Also updated the soft-DACs with cleaned up HDL. jshamlet 1340d 07h /open8_urisc/
267 Corrected the file description to indicate this is an example package. jshamlet 1340d 07h /open8_urisc/
266 Accidentally uploaded incorrect example file for Open8_cfg.vhd jshamlet 1340d 07h /open8_urisc/
265 Fixed a bug where "reg" wasn't being initialized with Poly_Init at reset. jshamlet 1432d 15h /open8_urisc/
264 Updated comments jshamlet 1442d 13h /open8_urisc/
263 Fixed a very old bug in the CPU core where autoincrements weren't affecting the upper register in the pair, causing it to loop around the lower 256 bytes. This only affected LDX/LDO, as the proper ALU signals were being generated in STO/STX and UPP. Wow, that bug has been in there for AGES.

Also separated the SDLC TX and RX interrupts so that they could be handled separately.
jshamlet 1442d 13h /open8_urisc/
262 Added comments to LCD controllers - specifically that reading either register 0 or 1 will return the ready status. This code was already present, but not mentioned in the register map. jshamlet 1451d 16h /open8_urisc/
261 Increased delay timer to 7 bits for button press detection. jshamlet 1458d 16h /open8_urisc/
260 Added missing comments for Sequential_Interrupts generic, as well as comments explaining portions of the CPU operations. jshamlet 1471d 15h /open8_urisc/
259 Fixed issue where Write_Fault wasn't defaulting to '0' when Write_Protect was set to FALSE,
Added a pulse interval measurement entity,
Fixed comments.
jshamlet 1471d 17h /open8_urisc/
258 Fixed write bug in o8_ltc2355_2p.vhd, added a newer Open8_cfg.vhd, and the sys_tick.vhd utility entity. jshamlet 1472d 15h /open8_urisc/
257 Fixed misnamed signal in o8_7seg.vhd and added a replacement switch interface that handles both static and pushbutton switches. jshamlet 1472d 15h /open8_urisc/
256 Removed unused generic from the status_led.vhd and cleaned up comments on the CPU jshamlet 1472d 16h /open8_urisc/
255 Modified code to make ModelSim happy (It didn't like the generate blocks for some reason). Also added a block describing the new generic. jshamlet 1472d 21h /open8_urisc/
254 Simplified the ISR address logic so that the upper 12 bits are constant (set by generic) and only the lower 4 bits are registered/computed. jshamlet 1473d 11h /open8_urisc/
253 Fixed spelling error in comment jshamlet 1473d 12h /open8_urisc/
252 (This time the CPU model was included...)
Added the ability to use unsigned offsets to the LDO/STO instructions. The original behavior of signed offsets is preserved if the Unsigned_Index_Offsets is left unset or set to FALSE. While inserting this code, pipeline registers were also inserted into the address generation logic for indexed instructions. This simplifies the final multiplexor and improves FMax at the slight expense of LDO/SDO now taking one additional clock cycle to execute.
jshamlet 1473d 12h /open8_urisc/
251 Added RAM write fault detection, which can be used to indicate a memory write violation by the CPU. This allows a clean shutdown in the event of a memory problem/program crash.

Fixed a bug in the status_led.vhd entity that kept the flashing light function from working. The new code uses a maximal length 24-bit LFSR to create long delays. This is more efficient than a binary counter, but results in non-exact frequencies as a function of SYSTEM_FREQUENCY / (2^24-1).

Added the ability to use unsigned offsets to the LDO/STO instructions. The original behavior of signed offsets is preserved if the Unsigned_Index_Offsets is left unset or set to FALSE. While inserting this code, pipeline registers were also inserted into the address generation logic for indexed instructions. This simplifies the final multiplexor and improves FMax at the slight expense of LDO/SDO now taking one additional clock cycle to execute.
jshamlet 1473d 12h /open8_urisc/
250 Removed monitor RAM from SDLC model, as it is now proven to work. jshamlet 1477d 20h /open8_urisc/
249 Added a 32-bit wide register and split the status_led core from o8_status_led.vhd, allowing it to be used as a subcomponent elsewhere. jshamlet 1489d 12h /open8_urisc/
248 Removed Default_Int_Flag generic from CPU, as it is duplicated by Supervisor_Mode. jshamlet 1489d 20h /open8_urisc/
247 Fixed problem where parallel interface was always forcing the data registers due to bad alias. jshamlet 1490d 13h /open8_urisc/
246 The system timer module now allows for an optional millisecond resolution (settable through a generic). This prescalar enable permits the timer to operate from 1 to 256 mS, which is useful for a variety of tasks, such as serial timeouts and watchdog timers. The enable is not software settable, as this would complicate the register interface and isn't generally useful in an HDL based SOC design.

The vector interface now has a parallel interface that runs beside the serial interface, and is useful for connecting to DIO cards or other parallel interfaces.
jshamlet 1490d 18h /open8_urisc/

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