| Rev |
Log message |
Author |
Age |
Path |
| 197 |
Fixed incorrect comments |
jshamlet |
1559d 12h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1559d 12h |
/open8_urisc/trunk/VHDL/ |
| 195 |
Added dual-port RAM core for SDLC interface. |
jshamlet |
1560d 07h |
/open8_urisc/trunk/VHDL/ |
| 194 |
Cleaned up licensing sections |
jshamlet |
1560d 07h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1560d 08h |
/open8_urisc/trunk/VHDL/ |
| 192 |
Added SDLC packet engine |
jshamlet |
1560d 08h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1560d 08h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1572d 06h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1573d 06h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1573d 09h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1575d 05h |
/open8_urisc/trunk/VHDL/ |
| 186 |
Merged the interrupt override logic into the case structure, simplifying how interrupts are processed. |
jshamlet |
1578d 05h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1578d 08h |
/open8_urisc/trunk/VHDL/ |
| 184 |
More file/entity renaming to match private versions. |
jshamlet |
1580d 07h |
/open8_urisc/trunk/VHDL/ |
| 183 |
Renamed core to o8_cpu to match new naming scheme |
jshamlet |
1580d 08h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1580d 08h |
/open8_urisc/trunk/VHDL/ |
| 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 |
1581d 04h |
/open8_urisc/trunk/VHDL/ |
| 180 |
Added additional Open8 compatible modules |
jshamlet |
1585d 08h |
/open8_urisc/trunk/VHDL/ |
| 177 |
Fixed comments in RTC module |
jshamlet |
2905d 09h |
/open8_urisc/trunk/VHDL/ |
| 176 |
Fixed documentation errors,
Modified uSec_Tick such that it is always generated regardless of the interval. |
jshamlet |
2910d 06h |
/open8_urisc/trunk/VHDL/ |
| 175 |
Added 4 and 8-bit LCD interfaces with backlight and contrast DACs |
jshamlet |
2910d 11h |
/open8_urisc/trunk/VHDL/ |
| 174 |
Added ROM/RAM wrappers |
jshamlet |
3105d 06h |
/open8_urisc/trunk/VHDL/ |
| 173 |
Added a couple of useful interfaces for detecting button presses and clock changes. |
jshamlet |
3105d 06h |
/open8_urisc/trunk/VHDL/ |
| 172 |
General code cleanup |
jshamlet |
3105d 06h |
/open8_urisc/trunk/VHDL/ |
| 171 |
Fixed comments for offsets 0x0 - 0x3 to indicate the read value |
jshamlet |
3105d 06h |
/open8_urisc/trunk/VHDL/ |
| 170 |
Added 24-bit resolution epoch timer / alarm clock |
jshamlet |
3105d 06h |
/open8_urisc/trunk/VHDL/ |
| 169 |
Corrected issue with CMP and SBC generating an inverted carry flag and added new constants to the package file to simplify interfacing new modules. |
jshamlet |
3160d 07h |
/open8_urisc/trunk/VHDL/ |
| 168 |
Simplified write data path logic,
Converted RTC to packed BCD,
Corrected several bugs in real time clock component, |
jshamlet |
3939d 03h |
/open8_urisc/trunk/VHDL/ |
| 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 |
3947d 01h |
/open8_urisc/trunk/VHDL/ |
| 164 |
Modified the data path to allow the bus to go idle while waiting for an interrupt. This makes it easier to debug code that uses the WAI instruction, as both Wr_Enable and Rd_Enable go low. |
jshamlet |
4582d 21h |
/open8_urisc/trunk/VHDL/ |
