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Documentation update (nw)

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AJR 2017-12-10 15:32:24 -05:00
parent 0306e6e119
commit e733af5b08
1 changed files with 15 additions and 1 deletions
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16
docs/source/techspecs/device_rom_interface.rst
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@ -41,7 +41,16 @@ rom description for the system, it will be automatically picked up as
the connected rom. An address map has priority over the region if
present in the machine config.
| void **set_rom**\ (const void \*base, UINT32 size);
| void **set_rom_endianness**\ (endianness_t endian)
| void **set_rom_data_width**\ (u8 width)
| void **set_rom_addr_width**\ (u8 width)
These methods, intended for generic devices with indefinite hardware
specifications, override the endianness, data bus width and address
bus width assigned through the constructor. They must be called from
within the device before **config_complete** time.
| void **set_rom**\ (const void \*base, u32 size);
At any time post- **interface_pre_start**, a memory block can be
setup as the connected rom with that method. It overrides any
@ -76,3 +85,8 @@ Using that interface makes the device derive from
**device_memory_interface**. If the device wants to actually use the
memory interface for itself, remember that AS_0/AS_PROGRAM is used by
the rom interface, and don't forget to upcall **memory_space_config**.
For devices which have outputs that can be used to address ROMs but
only to forward the data to another device for processing, it may be
helpful to disable the interface when it is not required. This can be
done by overriding **memory_space_config** to return an empty vector.