This register exists only in CPCs with 128K RAM (like the CPC 6128, or CPCs with [[Standard Memory Expansions]]). Note: In the CPC 6128, the register is a separate [[PAL16L8|PAL chip]] that assists the Gate Array chip. See its wiki page.
{|{{Prettytable|width: 700px; font-size: 2em;}}class="wikitable"|-| ''!Bit'' || ''!Value'' || ''!Function''
|-
| 7 || 1 || rowspan="2" | Gate Array MMR register