Changes
/* CSYNC signal */
When CRTC HSYNC is active, the Gate Array immediately outputs the palette colour black. If the HSYNC is set to 14 characters then black will be output for 14µs.
If a video graphics mode change is pending, the HSYNC pulse width needs to be at least 2µs for Gate Array to change the video graphics mode.
The HSYNC is modified before being sent to the monitor. It happens 2µs after activation of the CRTC HSYNC and stay a maximum of 4µs (signal is cut short if HSYNC width is greater than 6).
The Gate Array uses 2 internal counters to create its CSYNC signal:
* H06 which counts the number of CRTC characters processed during an HSYNC. H06 is incremented by the Gate Array for each CRTC character when CRTC HSYNC is active. The Gate Array activates the C-HSYNC signal when H06 reaches 2, and changes its graphics mode if a change was pending. It deactivates this signal when H06 reaches 6.
* V26 which counts the number of HSYNCs occuring during a VSYNC. V26 is incremented by the Gate Array when the CRTC signals an end of HSYNC. The Gate Array activates the C-VSYNC signal when V26 reaches 2. It deactivates this signal when V26 reaches 6.
