Varthall wrote:
So does it mean that it's a second clockport
Nope, the clockport is only the rightmost 22pins of the bottom header(P9B)
There aren`t any address,interrupt or chip select lines available to make a pseudo clockport ..
The top header(P9A) carries different signals (mainly D16-24, and the row and column strobes from the budgie chip.
As the previous poster explained, it was put there plug in another 1MB of chip ram, but for once Commodore had a good idea and shipped the 1200 with 2Mb onboard, so the top header is pretty useless.
As you`ve found out, there were several balls ups when they made the 1200.
Early machines had both sets of header pins built in, then to cut costs, they decided to only use the 22 pins needed for the clock, but sometimes they left in the wrong 22pins (on the left), othertimes they left them out completely!
