From 98bb5bd9f1f6a147c2161fd52c023074340f9313 Mon Sep 17 00:00:00 2001 From: Thomas Harte Date: Tue, 31 Jul 2018 23:01:11 -0400 Subject: [PATCH] Ensures flux bits are observable for two cycles rather than one; it should be 1us. --- Components/DiskII/DiskII.cpp | 8 +++++++- Components/DiskII/DiskII.hpp | 1 + 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/Components/DiskII/DiskII.cpp b/Components/DiskII/DiskII.cpp index d02afdb37..b80c68417 100644 --- a/Components/DiskII/DiskII.cpp +++ b/Components/DiskII/DiskII.cpp @@ -73,13 +73,18 @@ void DiskII::select_drive(int drive) { drives_[active_drive_].set_motor_on(motor_is_enabled_); } +// The read pulse is controlled by a special IC that outputs a 1us pulse for every field reversal on the disk. + void DiskII::run_for(const Cycles cycles) { if(preferred_clocking() == ClockingHint::Preference::None) return; int integer_cycles = cycles.as_int(); while(integer_cycles--) { const int address = (state_ & 0xf0) | inputs_ | ((shift_register_&0x80) >> 6); - inputs_ |= input_flux; + if(flux_duration_) { + --flux_duration_; + if(!flux_duration_) inputs_ |= input_flux; + } state_ = state_machine_[static_cast(address)]; switch(state_ & 0xf) { default: shift_register_ = 0; break; // clear @@ -200,6 +205,7 @@ void DiskII::set_disk(const std::shared_ptr &disk, int driv void DiskII::process_event(const Storage::Disk::Track::Event &event) { if(event.type == Storage::Disk::Track::Event::FluxTransition) { inputs_ &= ~input_flux; + flux_duration_ = 2; // Upon detection of a flux transition, the flux flag should stay set for 1us. Emulate that as two cycles. decide_clocking_preference(); } } diff --git a/Components/DiskII/DiskII.hpp b/Components/DiskII/DiskII.hpp index ccb3ce491..e95682101 100644 --- a/Components/DiskII/DiskII.hpp +++ b/Components/DiskII/DiskII.hpp @@ -121,6 +121,7 @@ class DiskII: ClockingHint::Preference clocking_preference_ = ClockingHint::Preference::RealTime; uint8_t data_input_ = 0; + int flux_duration_ = 0; }; }