Soldered. Would be nice to make that easier. On Saturday, September 3, 2022, B 9 <hacke...@gmail.com> wrote:
> I agree with Birt, those micrograbbers are finicky. How does the wire for > RexCPM connect securely in the T102? > > —b9 > > On Mon, Aug 29, 2022 at 5:25 PM Stephen Adolph <twospru...@gmail.com> > wrote: > >> Bit of a step forward in terms of REXCPM for T200. >> >> In experiments on a real T200 (not virtualT), I get the following nice >> result. >> >> Question: What memory is accessed in the "address hole" from 8000-9FFF" >> when Option ROM is selected (BANK3)? >> - ideally CP/M needs a full 64k >> - we have ram from A000-FFFF >> - we have "REXCPM RAM" from 0000-7FFF (when BANK3 is active) >> - ... and, we know that the 2nd 8K MAIN ROM is accessed from 8000-9FFF >> when BANK1 is active. >> >> Turns out that the Option ROM is actually chip selected for the entire >> address range from 0000-7FFF AND 8000-9FFF! >> --> when I run a "peeker" program that switches the option ROM on, and >> then reads back the memory value from an address, the laptop responds with >> the SAME value from 0000-1FFF and 8000-9FFF. >> >> --> if the option ROM socket had the A15 signal, then it could >> distinguish between the addresses. >> >> Said another way, >> If the Option ROM socket had a 33rd signal, A15, it could support 40KB >> worth of ROM memory. >> >> Maybe we can use something like this as an easy way to grab A15 from an >> internal location? >> >> https://www.ebay.ca/itm/253076010211?hash=item3aec8174e3:g: >> U6cAAOSwbmdZgrNP&amdata=enc%3AAQAHAAAA8O%2BKwe9wfSB0ZCf9NL04BWAEWnVZHPJ >> %2BT%2BHLBzEY1gVeSf7OTaXsaxnr6JwWChHUHT7prORrrMSMiHFq%2F1% >> 2Bjtp6bDA8e9kV2jiEeIOs3%2BGUpm7kzMlXvBrqcxGnckEHOk6dda >> qGdNkxwD%2BXT3mw6PRS4fvgyEb6F%2B%2B6n1HNINZA87pEbiSn7B6AZkEVbVi >> f2zL7S0cJbabZHXoFcWtu0WhUYfu56fE4OdjuyRx%2BafocbP2PnQ%2Fn% >> 2Fu9tCqD9TYlXbA7n%2F75Ph6UZCTUtcgh36XdeqMgK5xDfYo9C8GnRVZRhmXRc8TM82NB% >> 2FmMpp7aSL4fA%3D%3D%7Ctkp%3ABk9SR5DLx7_dYA >> >> >> Steve >> >> Therefore, the only "additional signal" needed, for REXCPM in T200, is to >> bring A15 to the memory area. >> >> >>
