Motorola 6809
The Motorola 6809 is an 8 -bit microprocessor and further development of the successful also supplied by Motorola model 6800, which was available in various versions from 1978. The combination of the two 8 -bit accumulator register of the processor a processing width of 16 bits is possible in the arithmetic area. The maximum clock rate is 2 MHz, the clock is provided either by a built- in microprocessor or an externally connected clock generator. The latter version is identified by a processor name suffix symbol " E".
Differences for 6800
- New commands to load effective address in register and to change the contents of registers
- New commands for affecting the Stacks
- New page register in order to improve the direct addressing mode
- Indexed addressing is augmented with new modes
- 16-bit relative branches could be used to create larger position independent programs
- 16-bit data processing
Use
It was used among others in several home computers and arcade games, there mostly as a second processor for sound and input control. In addition, he was, for example, Logic Analyzer 1630A/1631A, used by the company HP as standard CPU in screen-based instruments such as the in the signal generators 8115A, 8118A and 8175A, and in the 54200/54201A oscilloscopes and many other instruments. In the manuals of these devices are frequently found also measurement examples and test setups with the 6809th
Specifications
- 8 -bit processor
- 8 -bit-wide data bus
- Two 8 -bit data registers ( A and B), coupled to a 16 -bit data register ( D)
- Two 16-Bit-Stapelzeiger/Stackpointer (S and U)
- Two 16 -bit index register ( X and Y)
- Support for interrupts (interrupt )
- First 8 -bit microprocessor having 8 × 8 → 16-bit multiply instruction
- 59 machine instructions
- About 6800 transistors
Manufacturers and types of 6809
- AMS ( Austria Mikro Systeme International) S6809, S68A09, S68B09
- Fairchild Semiconductor F68B09P
- Fujitsu MBL68B09E
- Hitachi HD68B09
- Motorola MC6809L
- SGS -Thomson EF68B09J
- Thomson EF6809P
Pin assignment
The processor was offered in both the 40 -legged DIP/CERDIP- and in the 44 -legged PLCC package