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Rev Log message Author Age Path
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 1546d 20h /
208 Removed unnecessary package references jshamlet 1547d 06h /
207 Added a simple 8-bit, fixed asynchronous serial interface with compile time settable bit-rate, parity enable, and parity mode generics. jshamlet 1547d 23h /
206 Merged interrupt logic with other clocked process. jshamlet 1551d 18h /
205 More code and comment cleanup for the new SDLC engine jshamlet 1551d 18h /
204 Fixed more incorrect comments jshamlet 1551d 18h /
203 Removed an extra delay FF from the bitclock rising edge signal for the clock slave configuration to better center the rising edge pulse on the receive signal. jshamlet 1552d 00h /
202 Fixed receiver bug that caused false flag detection,
Split the large sdlc_serial_ctrl entity into sub-entities to make debugging easier.
jshamlet 1552d 01h /
201 Fixed comments regarding RX Checksum location jshamlet 1553d 22h /
200 Renamed dual-port buffer to match other entities. jshamlet 1553d 22h /
199 Added monitor ram for debugging and fixed issue with dual-port read path. jshamlet 1553d 23h /
198 Removed debugging memory jshamlet 1554d 07h /
197 Fixed incorrect comments jshamlet 1554d 07h /
196 Modified the update logic to allow direct writes to offset 0xFE for refreshing the clock status. This way, any write to the clock status register will immediately be undone. (Writing 0x00 to offset 0xFF is once-more ignored) jshamlet 1554d 07h /
195 Added dual-port RAM core for SDLC interface. jshamlet 1555d 02h /
194 Cleaned up licensing sections jshamlet 1555d 02h /
193 Fixed incorrect comment in o8_alu16.vhd. The value of the write to 0x1F doesn't matter, as the write itself triggers the calculation. jshamlet 1555d 03h /
192 Added SDLC packet engine jshamlet 1555d 03h /
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 1555d 03h /
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 1567d 01h /
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 1568d 01h /
188 Added a generic to alter the behavior of RTI so that it can optionally skip restoring the general purpose flags GP4 to GP7, allowing ISR's to make persistent changes to them. Also exported these flags to the top level for use outside the CPU. jshamlet 1568d 04h /
187 Added the CPU_Halt input, only now as an input to the instruction decoder. The CPU_Halt line will assert the registered CPU_Halt_Req, which will cause the instruction decoder to abort the current instruction, reset the PC, then enter a hold state until the line is deasserted. Additionally, a very minor bug that could cause the SMSK instruction to effectively execute twice if interrupted was fixed. Lastly, cleaned up the comments even more. jshamlet 1570d 00h /
186 Merged the interrupt override logic into the case structure, simplifying how interrupts are processed. jshamlet 1573d 00h /
185 1) Fixed an apparently long-standing bug where the interrupt bit wasn't being cleared after an RTI
2) Modified the program counter logic to be simpler. It now always increments, and states control the increment using the offset field. A new set of constants was added to replace the old states.
3) Modified the ALU to always use Operand1 instead of ALU_Ctrl.Data (and removed the field in the record). A new ALU command, ALU_GMSK, was added, as it was the only instruction to set the .Data field to something other than Operand1 (Int_Mask)
4) Modified the package file so that flag names match what the assembler calls them. FL_Z is now PSR_Z, FL_GP1 is now PSR_GP4, etc.
5) Cleaned up the comments and code formatting
jshamlet 1573d 03h /
184 More file/entity renaming to match private versions. jshamlet 1575d 02h /
183 Renamed core to o8_cpu to match new naming scheme jshamlet 1575d 03h /
182 Simplified the address generation logic at the expense of making LDX take one additional clock cycle. This allowed the address logic to be split out of the main state machine and simplified (greatly). During this process, a bug in SDO was found and fixed that caused it to return through the wrong pipe fill state wnen auto increment was disabled. jshamlet 1575d 03h /
181 Altered the RSP instruction to allow the stack pointed to either be restored from registers or stored to registers based on the status of a processor bit. Also modified LDX to simplify the address logic. jshamlet 1575d 23h /
180 Added additional Open8 compatible modules jshamlet 1580d 03h /

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