Category:Oric Atmos

Based on a 1 MHz MOS Technology 6502 CPU, the Oric-1 came in 16 KB or 48 KB RAM variants for £129 and £169 respectively, matching the models available for the popular ZX Spectrum and undercutting the price of the 48 KB version of the Spectrum by a few pounds. The circuit design requires 8 memory chips, one chip per data line of the CPU. Due to the sizing of readily available memory chips the 48 KB model has 8 * 8 KB (64 KBit) chips, making a total of 64 KB. As released only 48 KB is available to the user, with the top 16 KB of memory overlaid by the BASIC ROM; The optional disc drive unit contains some additional hardware that allows it to enable or disable the ROM, effectively adding 16 KB of RAM to the machine. This additional memory is used by the system to store the Oric DOS software.[citation needed] Both Oric-1 versions have a 16 KB ROM containing the operating system and a modified BASIC interpreter.

The Oric-1 has a sound chip, the programmable General Instrument AY-3-8910.

Two graphics modes are handled by a semi-custom ASIC (ULA) which also manages the interface between the processor and memory. The two modes are a “LORES” (low resolution) text mode (though the character set can be redefined to produce graphics) with 28 rows of 40 characters and a “HIRES” (high resolution) mode with 200 rows of 240 pixels above three lines of text. Like the Spectrum, the Oric-1 suffers from attribute clash–albeit to a much lesser degree in HIRES mode, since 2 different colours can be defined for each 6×1 block of 6 pixels,

The system has a built-in television RF modulator as well as RGB output. A standard audio tape recorder can be used for external storage. There is a Centronics compatible printer interface. [Text from Wikipedia]