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Created page with '== LK1,LK2,LK3 Manufacturer ID == LK1,LK2,LK3 connect to [[8255|PPI]] Port B, Bit1-3. The links select the manufacturer name (which is displayed by the BIOS in the power-up mess…'
== LK1,LK2,LK3 Manufacturer ID ==
LK1,LK2,LK3 connect to [[8255|PPI]] Port B, Bit1-3. The links select the manufacturer name (which is displayed by the BIOS in the power-up message). These LKs exist on all CPC mainboards (in CPC Plus/GX4000 schematics they are named LK101,LK102,LK103).
== LK4 Screen Refresh Rate ==
LK4 connects to [[8255|PPI]] Port B, Bit4. The link tells the BIOS whether it should set-up the [[CRTC]] for 50Hz or 60Hz refresh rate.
== CPC6128 : LK5,LK6,LK8 ==
The CPC6128 contains 128K RAM, RAM banking is controlled by a PAL (which assists its [[Gate Array]]). However, the 6128 mainboard can be also used for 64K computers - in that case, only 64K would be installed, the PAL would be missing, and LK5,LK6,LK8 would be installed (bypassing the RAM banking logic, and passing signals directly to unbanked RAM).
== DDI-1 : LK1 ==
In the DDI-1, LK1 connects ''both'' to the Expansion Port /EXP pin, ''and'' to the AMSDOS ROM bank number selection logic. The latter one allow to map AMSDOS to bank 7 (default), or bank 0. If AMSDOS sees itself mapped to bank 0, then it does automatically load & start the boot sector from drive A (equivalent as when typing |CPM after power-up).
== DDI-1 : LK2,LK3 ==
In DDI-1, LK2-LK3 connect to the Disc Data Separator. Purpose...?
== CPC6128 : LK7 ==
== CPC Plus : LK105 ==
== CPC Plus : R128,R129,R130 ==
== CPC Plus Cartridges : LK1-LK6 ==
LK1,LK2,LK3 connect to [[8255|PPI]] Port B, Bit1-3. The links select the manufacturer name (which is displayed by the BIOS in the power-up message). These LKs exist on all CPC mainboards (in CPC Plus/GX4000 schematics they are named LK101,LK102,LK103).
== LK4 Screen Refresh Rate ==
LK4 connects to [[8255|PPI]] Port B, Bit4. The link tells the BIOS whether it should set-up the [[CRTC]] for 50Hz or 60Hz refresh rate.
== CPC6128 : LK5,LK6,LK8 ==
The CPC6128 contains 128K RAM, RAM banking is controlled by a PAL (which assists its [[Gate Array]]). However, the 6128 mainboard can be also used for 64K computers - in that case, only 64K would be installed, the PAL would be missing, and LK5,LK6,LK8 would be installed (bypassing the RAM banking logic, and passing signals directly to unbanked RAM).
== DDI-1 : LK1 ==
In the DDI-1, LK1 connects ''both'' to the Expansion Port /EXP pin, ''and'' to the AMSDOS ROM bank number selection logic. The latter one allow to map AMSDOS to bank 7 (default), or bank 0. If AMSDOS sees itself mapped to bank 0, then it does automatically load & start the boot sector from drive A (equivalent as when typing |CPM after power-up).
== DDI-1 : LK2,LK3 ==
In DDI-1, LK2-LK3 connect to the Disc Data Separator. Purpose...?
== CPC6128 : LK7 ==
== CPC Plus : LK105 ==
== CPC Plus : R128,R129,R130 ==
== CPC Plus Cartridges : LK1-LK6 ==
