04-23-2023, 03:15 PM
Early integrated circuit designs are fascinating and a thing of beauty.
I came across a blog article that got my attention for the amount of detail revealed in analyzing a calculator Rockwell LSI. Rockwell four-phase PMOS LSI were used in various brands of calculators in the early 70s. This article highlights the details of one such LSI. If you're a fan of early hardware and schematics like I am, this article does not disappoint!
Decimal point control
Look for example at this beautiful design for a decimal point decoder to display the decimal point:
and its schematic:
Segment driver
The segment driver converts a digit to its 9 segment display output (a VFD tube):
to light segments a to i (and decimal point):
Transistors, resistors, capacitors and gates
A lot of details are explained, such as the four-phase delay clock gate:
Links
Reverse-engineering an early calculator chip with four-phase logic
Reverse-engineering the clock chip in the first MOS calculator
Reverse-engineering the multiplication algorithm in the Intel 8086 processor
Reverse-engineering the division microcode in the Intel 8086 processor
The Texas Instruments TMX 1795: the (almost) first, forgotten microprocessor also features 4004, 8008, AL1, Viatron 2101, MP944 / F-14 CADC (F14 fighter flight control system), TMS 0100 calculator-on-a-chip / microcontroller
- Rob
I came across a blog article that got my attention for the amount of detail revealed in analyzing a calculator Rockwell LSI. Rockwell four-phase PMOS LSI were used in various brands of calculators in the early 70s. This article highlights the details of one such LSI. If you're a fan of early hardware and schematics like I am, this article does not disappoint!
Decimal point control
Look for example at this beautiful design for a decimal point decoder to display the decimal point:
and its schematic:
Segment driver
The segment driver converts a digit to its 9 segment display output (a VFD tube):
to light segments a to i (and decimal point):
Transistors, resistors, capacitors and gates
A lot of details are explained, such as the four-phase delay clock gate:
Links
Reverse-engineering an early calculator chip with four-phase logic
Reverse-engineering the clock chip in the first MOS calculator
Reverse-engineering the multiplication algorithm in the Intel 8086 processor
Reverse-engineering the division microcode in the Intel 8086 processor
The Texas Instruments TMX 1795: the (almost) first, forgotten microprocessor also features 4004, 8008, AL1, Viatron 2101, MP944 / F-14 CADC (F14 fighter flight control system), TMS 0100 calculator-on-a-chip / microcontroller
- Rob