Kyp escribió: ↑28 Dic 2022, 10:04TR6 es un parche de última hora. ... No tiene nada que ver con el bus flotante.
No sé si estoy entiendo esto bien pero, por aclararlo, cito a Phil Ruston de su documento sobre
DiagROM 1.59 de Agosto de 2022:
1. ULA Analysis:
a) Attempts to determine the ULA type based on the reaction of the EAR input after changing
port 254 bits 4 and 5.
b) Checks the floating bus effect is present (an effect used by some games to synchronize
graphics routines etc). It involves reading an unimplemented port and examining the data that
appears there (it should be whatever byte the ULA was processing at the time, or $FF). The
floating bus test fails if the spider mod on Issue 2 boards (or TR6 on Issue3-6) is not working,
and the effect is absent on early Spectrums that have the “dead cockroach” modification. The
black Amstrad Spectrum 128s (+2A / +3) altered the bus sharing circuit and the floating bus
will not be detected (note: in recent years a similar effect was discovered on these machines
but it is detected differently).
o, como muestra, un extracto de Spectrum Computing:
I've completed the spider mod using that as a guide, much tidier than having it straddling the CPU, my diag cartridge confirms the floating bus is present so I guess that means it's working.
¿estamos malintrerpretando algo?