This table lists the known ICs used, with their part number, manufacturer and type number.
{|{{Prettytable|width: 700px; font-size: 2em;}}|''Part number ''||''Manufacturer ''||''Type number (note 3) ''|-|UM6845 ||UMC ||0 |-|HD6845S ||Hitachi ||0 |-|UM6845R ||UMC ||1 |-|MC6845 ||Motorola ||2 |-|AMS40489 ||Amstrad ||3 (note 1) |-|??? ||Amstrad? ||4 (note 2) |}
'''NOTES'''
NOTES: 1. The CRTC functionality is integrated into the CPC+ ASIC. This type exists only in the CPC464+,CPC6128+ and GX4000.
The CRTC functionality is integrated into the CPC+ ASIC2. This type exists only in the CPC464+,CPC6128+ and GX4000. As far as I know, this type exists only in "cost-down" CPC6128 systems. In the "cost-down" CPC6128, the CRTC functionality is integrated into a single ASIC IC. This ASIC is often refered to as the "Pre-ASIC" because it preceeded the CPC+ ASIC. 3. In the Amstrad community each 6845 implementation has been assigned a type number. This type identifies a group of implementations which operate in exactly the same way.
As far as I know, the type number system was originally used by demo programmers.
In most cases, the type of the detected 6845 is reported.
4. As far as I know, the KC compact used HD6845S only.
The 6845 is selected when bit 14 of the I/O port address is set to "0". Bit 1 and 0 of the I/O port address define the function to access. The remaining bits can be any value, but it is adviseable to set these to "1" to avoid conflict with other devices in the system.