Atari Lynx
The Atari Lynx is a hand-held cartridge game console released by the Atari Corporation in September of 1989 in the US. Europe and Japan customers could buy the console a few months later in early 1990. The Atari Lynx display was a liquid-crystal color screen.
The Lynx II was released in 1991 in an effort to make the machine more compact, and introduce a longer battery life, which was the main gripe of many gamers. Where the Lynx had a battery life of 3-4 hours, the Nintendo Gameboy could be played all day. Of course, technically the Lynx was far superior, but that doesn't hold the interest of a gamer if the batteries are dead.
The Lynx II was sold at a lower price point of $99 in an effort to win back some market share. But in 1993 Atari shifted its attention away from the Lynx towards the development of the Jaguar home console
Like the Lynx I, the II used the same 8/16-bit hybrid architecture, powered by a 65C02 8-bit CPU running at 16MHz and a custom 16-bit blitter that took the graphics to a whole other level compared to the monochrome Gameboy from Nintendo that was released earlier in 1989.
The Lynx started as the Handy Game project and was developed at Epyx by two former Commodore Amiga designers. Even though the machine was technically superior to the Gameboy, there were only 73 games published for the Lynx. The device was ultimately discontinued in 1995.
Technical Specifications
- Mikey 8-bit custom CMOS chip containing:
- 8-bit 65SC02 CPU @4MHz
- Sound Engine: 4 channels each with an 8-bit DAC
- Video DMA driver for the Color LCD:
- 160x102 pixels
- 4096 colors
16 colors per scanline
- variable framerate up to 75 fps
- 'Unlimited' number of blitter sprites with collision detection
- Hardware sprite scaling, distortion and tilting
- Hardware decoding of compressed sprite data
- Hardware clipping and multi-directional scrolling
- Math engine (16bit x 16bit multiplication, 32-bit by 16-bit division, parallel processing)
CPU - The Motorola 6502
The 6502 is an 8-bit MicroProcessor designed by MOS Technology. The team was led by Chuck Peddle and had also worked on the Motorola 6800. The 6502 is a simplified, but faster and cheaper design than the 6800.
The 6502 was introduced in 1975 and was the cheapest microprocessor on the market. Together with the Zilog Z80, the 6502 helped start the home computer revolution of the 1980s. The 6502 was used in a wide range of devices: the Atari 2600, the 8-bit Atari home computers, the Apple II, the Nintendo Entertainment System, the Commodore 64, the BBC Micro and many others. All used the 6502 or a variation of it.
The 6502 is a 1MHz design, while the 6502A is designed for 2MHz. The 6502A is 100% compatible with the original 6502.
Commodore soon bought MOS Technology, but conitnued to sell the microprocessor to competitors and licensed the design to other manufacturers.
Source: WikiPedia - MOS Technology 6502The 650x Instruction Set
| Mnemonic | Operation | Description |
|---|---|---|
| ADC | Add with Carry | Adds a memory location and the carry bit to the accumulator. |
| AND | Logical AND | Performs a logical AND between memory and the accumulator. |
| ASL | Arithmetic Shift Left | Shifts all bits one position to the left (in memory or accumulator). |
| BCC | Branch on Carry Clear | Branches to a new address if the carry flag is clear (0). |
| BCS | Branch on Carry Set | Branches to a new address if the carry flag is set (1). |
| BEQ | Branch on Equal (Zero Set) | Branches to a new address if the zero flag is set (1). |
| BIT | Bit Test | Tests bits in memory with the accumulator without modifying the accumulator. |
| BMI | Branch on Minus | Branches to a new address if the negative flag is set (1). |
| BNE | Branch on Not Equal | Branches to a new address if the zero flag is clear (0). |
| BPL | Branch on Plus | Branches to a new address if the negative flag is clear (0). |
| BRK | Force Break | Forces an interrupt request and pushes status and PC to the stack. |
| BVC | Branch on Overflow Clear | Branches to a new address if the overflow flag is clear (0). |
| BVS | Branch on Overflow Set | Branches to a new address if the overflow flag is set (1). |
| CLC | Clear Carry Flag | Clears the processor carry flag. |
| CLD | Clear Decimal Mode | Clears the processor decimal mode flag. |
| CLI | Clear Interrupt Disable | Clears the interrupt disable flag, allowing maskable interrupts. |
| CLV | Clear Overflow Flag | Clears the processor overflow flag. |
| CMP | Compare Accumulator | Compares the contents of a memory location with the accumulator. |
| CPX | Compare X Register | Compares the contents of a memory location with the X register. |
| CPY | Compare Y Register | Compares the contents of a memory location with the Y register. |
| DEC | Decrement Memory | Subtracts one from the value held at a specified memory location. |
| DEX | Decrement X Register | Subtracts one from the X register. |
| DEY | Decrement Y Register | Subtracts one from the Y register. |
| EOR | Exclusive OR | Performs a logical Exclusive OR between memory and the accumulator. |
| INC | Increment Memory | Adds one to the value held at a specified memory location. |
| INX | Increment X Register | Adds one to the X register. |
| INY | Increment Y Register | Adds one to the Y register. |
| JMP | Jump | Sets the program counter to a new address. |
| JSR | Jump to Subroutine | Pushes the return address to the stack and jumps to a new address. |
| LDA | Load Accumulator | Loads a byte of memory into the accumulator. |
| LDX | Load X Register | Loads a byte of memory into the X register. |
| LDY | Load Y Register | Loads a byte of memory into the Y register. |
| LSR | Logical Shift Right | Shifts all bits one position to the right (in memory or accumulator). |
| NOP | No Operation | Performs no operation, consuming 2 machine cycles. |
| ORA | Logical Inclusive OR | Performs a logical OR between memory and the accumulator. |
| PHA | Push Accumulator | Pushes a copy of the accumulator onto the stack. |
| PHP | Push Processor Status | Pushes a copy of the status flags onto the stack. |
| PLA | Pull Accumulator | Pulls a byte from the stack into the accumulator. |
| PLP | Pull Processor Status | Pulls a byte from the stack into the processor status flags. |
| ROL | Rotate Left | Rotates all bits one position left through the carry flag. |
| ROR | Rotate Right | Rotates all bits one position right through the carry flag. |
| RTI | Return from Interrupt | Pulls the processor flags and program counter from the stack. |
| RTS | Return from Subroutine | Pulls the program counter from the stack and resumes execution. |
| SBC | Subtract with Carry | Subtracts memory and the inverse of the carry bit from the accumulator. |
| SEC | Set Carry Flag | Sets the processor carry flag. |
| SED | Set Decimal Flag | Sets the processor decimal mode flag. |
| SEI | Set Interrupt Disable | Sets the interrupt disable flag, preventing maskable interrupts. |
| STA | Store Accumulator | Stores the contents of the accumulator in memory. |
| STX | Store X Register | Stores the contents of the X register in memory. |
| STY | Store Y Register | Stores the contents of the Y register in memory. |
| TAX | Transfer Accumulator to X | Copies the current value of the accumulator into the X register. |
| TAY | Transfer Accumulator to Y | Copies the current value of the accumulator into the Y register. |
| TSX | Transfer Stack Pointer to X | Copies the current value of the stack pointer into the X register. |
| TXA | Transfer X to Accumulator | Copies the current value of the X register into the accumulator. |
| TXS | Transfer X to Stack Pointer | Copies the current value of the X register into the stack pointer. |
| TYA | Transfer Y to Accumulator | Copies the current value of the Y register into the accumulator. |