Subversion Repositories neorv32

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==== System Configuration Information Memory (SYSINFO)

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|=======================
| Hardware source file(s): | neorv32_sysinfo.vhd | 
| Software driver file(s): | neorv32.h |
| Top entity port:         | none | 
| Configuration generics:  | * | most of the top's configuration generics
| CPU interrupts:          | none | 
|=======================

**Theory of Operation**

The SYSINFO allows the application software to determine the setting of most of the processor's top entity
generics that are related to processor/SoC configuration. All registers of this unit are read-only.

This device is always implemented – regardless of the actual hardware configuration. The bootloader as well
as the NEORV32 software runtime environment require information from this device (like memory layout
and default clock speed) for correct operation.

.SYSINFO register map
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| Address | Name [C] | Function
| `0xffffffe0` | _SYSINFO_CLK_         | clock speed in Hz (via top's _CLOCK_FREQUENCY_ generic)
| `0xffffffe4` | _SYSINFO_USER_CODE_   | custom user code, assigned via top's _USER_CODE_ generic
| `0xffffffe8` | _SYSINFO_FEATURES_    | specific hardware configuration (see next table)
| `0xffffffec` | _SYSINFO_CACHE_       | cache configuration information (see next table)
| `0xfffffff0` | _SYSINFO_ISPACE_BASE_ | instruction address space base (defined via `ispace_base_c` constant in the `neorv32_package.vhd` file)
| `0xfffffff4` | _SYSINFO_IMEM_SIZE_   | internal IMEM size in bytes (defined via top's _MEM_INT_IMEM_SIZE_ generic)
| `0xfffffff8` | _SYSINFO_DSPACE_BASE_ | data address space base (defined via `sdspace_base_c` constant in the `neorv32_package.vhd` file)
| `0xfffffffc` | _SYSINFO_DMEM_SIZE_   | internal DMEM size in bytes (defined via top's _MEM_INT_DMEM_SIZE_ generic)
|=======================


._SYSINFO_FEATURES_ bits
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| Bit | Name [C] | Function
| `0`  | _SYSINFO_FEATURES_BOOTLOADER_       | set if the processor-internal bootloader is implemented (via top's _INT_BOOTLOADER_EN_ generic)
| `1`  | _SYSINFO_FEATURES_MEM_EXT_          | set if the external Wishbone bus interface is implemented (via top's _MEM_EXT_EN_ generic)
| `2`  | _SYSINFO_FEATURES_MEM_INT_IMEM_     | set if the processor-internal DMEM implemented (via top's _MEM_INT_DMEM_EN_ generic)
| `3`  | _SYSINFO_FEATURES_MEM_INT_DMEM_     | set if the processor-internal IMEM is implemented (via top's _MEM_INT_IMEM_EN_ generic)
| `4`  | _SYSINFO_FEATURES_MEM_EXT_ENDIAN_   | set if external bus interface uses BIG-endian byte-order (via package's `wb_big_endian_c` constant)
| `5`  | _SYSINFO_FEATURES_ICACHE_           | set if processor-internal instruction cache is implemented (via _ICACHE_EN_ generic)
| `14` | _SYSINFO_FEATURES_HW_RESET_         | set if on-chip debugger implemented (via _ON_CHIP_DEBUGGER_EN_ generic)
| `15` | _SYSINFO_FEATURES_HW_RST_           | set if a dedicated hardware reset of all core registers is implemented (via package's _dedicated_reset_c_ constant)
| `15` | _SYSINFO_FEATURES_HW_RST_           | set if a dedicated hardware reset of all core registers is implemented (via package's _dedicated_reset_c_ constant)
| `16` | _SYSINFO_FEATURES_IO_GPIO_          | set if the GPIO is implemented (via top's _IO_GPIO_EN_ generic)
| `17` | _SYSINFO_FEATURES_IO_MTIME_         | set if the MTIME is implemented (via top's _IO_MTIME_EN_ generic)
| `18` | _SYSINFO_FEATURES_IO_UART0_         | set if the primary UART0 is implemented (via top's _IO_UART0_EN_ generic)
| `19` | _SYSINFO_FEATURES_IO_SPI_           | set if the SPI is implemented (via top's _IO_SPI_EN_ generic)
| `20` | _SYSINFO_FEATURES_IO_TWI_           | set if the TWI is implemented (via top's _IO_TWI_EN_ generic)
| `21` | _SYSINFO_FEATURES_IO_PWM_           | set if the PWM is implemented (via top's _IO_PWM_EN_ generic)
| `22` | _SYSINFO_FEATURES_IO_WDT_           | set if the WDT is implemented (via top's _IO_WDT_EN_ generic)
| `23` | _SYSINFO_FEATURES_IO_CFS_           | set if the custom functions subsystem is implemented (via top's _IO_CFS_EN_ generic)
| `24` | _SYSINFO_FEATURES_IO_TRNG_          | set if the TRNG is implemented (via top's _IO_TRNG_EN_ generic)
| `25` | _SYSINFO_FEATURES_IO_SLINK_         | set if the SLINK is implemented (via top's _SLINK_NUM_TX_ / _SLINK_NUM_RX_ generics)
| `26` | _SYSINFO_FEATURES_IO_UART1_         | set if the secondary UART1 is implemented (via top's _IO_UART1_EN_ generic)
| `27` | _SYSINFO_FEATURES_IO_NEOLED_        | set if the NEOLED is implemented (via top's _IO_NEOLED_EN_ generic)
|=======================