lvd wrote:it couldn't be hardware equivalent since nobody knows internal logic structure of KR1818VG93.
Nobody knows ... but I know.
KOE wrote:Nobody knows ... but I know.
KOE wrote:1 mb ram -> 7ffd (pentagon standard)
ram above 1 mb -> additional port
port eff7 bit5 enables additional port. The address of this port is not appointed now. It can be additional register in the same 7ffd address.
Video modes (except standard zx screen) is under development now.
VELESOFT wrote:As absolutly best feature can be - ZX ULA timing emulation. If new Pentagon can use also screen and CPU timing as original ZX Spectrum 128, then can use any original software without modifications.
VELESOFT wrote:Or use readable port 7FFD.
VELESOFT wrote:INT will after screen as on original Pentagons ?
VELESOFT wrote:AY ABC/ACB switching - AY clk switching (Pentagon/ZX128)
VELESOFT wrote: support ULA timing of: PENTAGON, SCORPION, ZX SPECTRUM 128
VELESOFT wrote: new 16colour mode with palette (screen data is linear as in SAM COUPE)
KOE wrote:Now the mixing is left = b+c; right = a + b; the channels are mixed digitally in fpga. External DAC has 2 channels (left and right). Channel mixing can be easily changed if one needs it.
KOE wrote:The computer name is "Pentagon", that's why only Pentagon mode represents my interests. As an expection I can support standart ZX128 mode but all other modes/timings will not be supported.
VELESOFT wrote:You are right, only Pentagon and ZX128 is two big standards. CPU timing of other machines is not supported in software.
lvd wrote:Which ZX128 exactly? as far as I know there are different zx128's with different timings and even with different distribution of slow-fast pages. pentagon is definitely better - at least it is rigid.
You all have nothing but old zx128, so you call it 'standard'
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