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Timex 2000 series

No change in size, 18:41, 10 November 2015
m
JEDEC KB
| rom =
| ram =
| rampage = ?×8kB×8KB
| manu = Timex Portugal
| volume =
| cpu = [[Z80|Z80A]] @ ?MHz
| rom =
| ram = 48kB48KB| rampage = 6×8kB 6×8KB fixed
| manu = Timex Portugal
| volume =
| rom =
| ram =
| rampage = ?×8kB×8KB
| manu = Timex
| volume =
* The TC2068 and TS2068 have RGB signals on their expansion bus. The TC2048 lacks these signals.
There are also two modified versions of the TC2048; the TC2128 (Rebuiltion or similar) and the TC2144 (by Jarek Adamski). The TC2128 extends the TC2048 to 128kB 128KB using the [[ZX Spectrum 128]] memory scheme. The TC2144 does the same but provides an extra 16kB 16KB of memory between 0x8000 and 0xc000. Both upgrades allow the ULA to use the shadow screen in Bank 7 giving the machine a total of four screen areas.
Although the Timex machines are similar to the 48K machine there are some timing differences:
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The Timex machines feature a horizontal memory management unit. In the TS2068 and TC2068 it is used to support the extended BASIC and cartridges plugged into the dock. It is present in the TC2048 but there is no direct way to connect anything to it (although the refresh signals are available to connect an additional 128kB 128KB of RAM to the horizontal MMU).
Memory is paged in 8K banks from either the DOCK or the EX-ROM, but these banks are mutually exclusive—you cannot page in a bank from both simultaneously. Both DOCK and EX-ROM banks are uncontended. Bit 7 of port 0xff determines which bank to use (0=DOCK, 1=EX-ROM). Port 0xf4 determines which banks are to be paged in with each bit referring to the relevant bank (0–7 or 0′–7′). When memory is being paged, interrupts should be disabled and the stack should be in an area which is not going to change.

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