User:Asgalon/LH5801

LH5801 The LH5801 is an 8-bit microprocessor unit (MPU) in static CMOS technology produced by the Sharp Corporation from around 1980 to mid/late 1980ies (exact dates to be researched). It was used in the Sharp PC-1500 pocket computer series.

Overview
The processor features an 8-bit wide data bus and 16 bit wide address bus, which allows 64KB of main memory. A 1-bit memory enable signal allows addressing of a further 64KB of external memory in direct access for a total of 128KB capacity. The processor has 3 16-bit exclusive registers P, S and W, an 8-bit accumulator, 8 bit status register and 3 general purpose 16-bit registers named U, X and Y, which can be addressed as separate 8-bit registers (for example UL and UH). The processor has a timer function, three types of interrupt (Maskable, non-maskable and timer), DMA and multiprocessor capabilities, memory access control functionality, an 8-bit input port with clock signal for external latch, memory backup function and LCD back plate control. .

The processor works with a clock rate of 2.6MHz which yields an internal machine cycle of 1.3MHz for a minimum instruction execution time of 1.3µs for single cycle instructions.

History
The actual release date has to be researched, probably around 1980. Detailed information about the processor were made available to the public in English in 1983, before that most users were restricted to using BASIC as programming language in the pocket computers using this CPU.

Architecture
The processor is an 8-bit CISC CPU with a basic design similar to the Z80, but with additional I/O capabilities such as direct LCD display control circuitry and connectors, targeted for its main usage in Sharp' series of pocket computers.

Block diagram
The block diagram was published in the PC-1500 Technical Reference Manual in 1983.

Connectors
The processor as used in the Sharp PC-1500 is packaged in a 76 pin QFP variant (missing detailed measurements/documentation). The pins are numbered counterclockwise starting with the dot-marked corner.

Address modes
The names are inserted here for clarification and are not taken from original documentation.