#### Issue 4 Model - Xilinx Artix-7™ A15T FPGA (XC7A15T) implementing: - CPU:Z80N CPU with extended instruction set @ 3.5/7/14/28 MHz - All standard ZX Spectrum and Timex video-modes with the addition of Layer 2, Layer 3 and LoRes video with 9 bit colour and hardware scrolling - TurboSound compatibility (3 PSGs) - 3 x AY-3-8912 or YM-2149 compatible PSG audio chips with stereo output - Covox™/Soundrive™/SpecDrum™ compatible digital audio - Selectable DMA controller (Z80DMA and zxnDMA) - Amiga™ like Copper hardware - Hardware Sprite Engine - EnhancedULA extending legacy Spectrum and Timex modes to 256 colours out of a 512 colour palette - Multiface compatible NMI handling hardware - Two programmable UARTs - Programmable CTC chip (8 channels) - I₂C bus - SPI bus - PS/2 keyboard and mouse controller - Two joystick controllers compatible with Kempston, Sinclair and Cursor standards - divMMC interface with an external SD card slot (as well as additional possibility for a secondary internal micro SD card slot, only via expert soldering at user's own risk) - Memory:2MB SRAM standard - 58 key laptop-style low profile tactile matrix keyboard - Video out ports: RGB / VGA Analog and HDMI-compatible Digital Video Port - Stereo Audio Out port - Two multipurpose controller and I/O ports for joystick and serial communications - Tape support, with joint Mic and Ear ports - Original external bus expansion port - I₂C RTC (Real Time Clock) device (DS-1307) - Wi-Fi module, with a full TCP/IP stack (ESP8266). - Internal accelerator expansion port (for optional Raspberry Pi Zero accelerator) - On board GPIO for user expansion - Multicore capability