Zx80, load and Save, TV sound

[ikjordan]

Adds the following features:

TV sound emulation

• Select between sync sounds as generated by TV or by Chroma card
• Chroma sound generates vsync sound when the display is not synchronised
• Sync sound genarates sound on VSYNC (ZX81) or HSYNC and VSYNC (ZX80)
• Can now play 1-bit music such the beatles.p, or the programs created by kmurta

More accurate ZX80 hardware emulation

Can now select:

• ZX80 hardware with 4K and 8K ROM
• ZX81 hardware with Sinclair and BigBang ROMs
• Both the ZX81 and ZX80 versions of Metropolis now run correctly
• The ZX80 hardware emulation is based on the model used in the latest versions of the EightyOne emulator

Code and memory optimisations

Now 15 to 20% faster so:

• Full speed chroma emulation
• Full speed sound emulation

Optional Load and Save graphics and sound

• Relive the 1980s with Load and Save effects at cassette speed!
• Generated through the IN and OUT commands executed during Load and Save. These generate the characteristic display and triggers sound pulses to be played through the speakers. The save sounds generated for both the 4K and 8K ROMs have been recorded as wav files and then successfully loaded into the EightyOne emulator
• When loading, picozx81 will read a p file and generate values which the ROM reads through IN statements. On the ZX81 and ZX80 with 8K ROM this causes sync pulses which generate sound and visual effects. Note: A program cannot be loaded directly from a wav file
• Load and Save sound generation will work regardless of which sound mode is selected in the emulator

No longer patches the ROM to detect load and save

• This removes the risk of inaccurate emulation of pseudo hi-res displays

Run-time selectable LCD and VGA displays (for PICOZX with LCD)

• The PICOZX + LCD code generates LCD output by default. To enable VGA output either hold down the the Fire button at start-up, or enable VGA in the config file