Texas Instruments TMC0598 Multi-Register Chip

• Features

Texas Instruments announced on September 16, 1975 with the SR-52 their first Keystroke Programmable Handheld Calculator based on the TMC0500 Building Blocks for Scientific and Programmable Calculators introduced already in January 1974 with the SR-50 “Slide Rule” calculator. While the SR-50 used only the minimum configuration of this groundbreaking architecture combining the TMC0501 Arithmetic Chip and one TMC0521 SCOM (Scanning Read-Only Memory) Chip with the necessary display drivers for its 14-digit LED display plus power supply and clock generation, went the SR-52 a step ahead and made full use of the TMC0500 Building Blocks. The TI Programmable 59 – nicknamed SR-52 II - was introduced in May 1977 as successor of the SR-52 and perfectly applied Moore’s Law integrating more memory capacity in smaller packages while lowering complexity. A closer look at the PCB (printed circuit board) of the TI-59 reveals a total of nine PMOS (P-channel Metal–oxide Semiconductor) chips:

• TMC0501E: Enhanced Arithmetic Chip – Register Processor with five 16-digit Registers and segment decoder/driver
• TMC0582, TMC0583: TMC0580 Double Scanning and Read-Only Memory Chip – 2.5k*13 Bits Instruction Memory with serial interface to Arithmetic Chip, 32 Constants with 16 digits, eight 16-digit Registers and 16-digit display scanning, each
• TMC0571: TMC0560 Bare Read-Only Memory Chips – 1k*13 Bits Instruction Memory with serial interface to Arithmetic Chip for a combined 6k*13 Bits Instruction Memory
• TMC0594: Magnetic I/O Chip – Four channel interface for magnetic card reader to save and load programs with up to 480 steps
• TMC0598*4: Four Multi-Register Chips – 240*8 Bits Random Access Memory with 4-bit I/O Bus to Arithmetic Chip, stores 240 program steps or 30 numbers of 16 digits, each

The TMC0598 Multi-Register Chip integrates 240*8 Bits RAM (Random Access Memory) storing 240 program steps or 30 numbers of 16 digits, each and accessible through a 4-bit bidirectional I/O bus. The design of the TMC0598 with one Chip Select (C.S.) and two Address pins (ADD0, ADD 1) allows for both compact designs with stacking two by two chips, each in a piggyback manner with cutting one of the two Address pins and large designs with an external address decoder activating the Chip Select pin:

Address TMC0598 Stack 1 TMC0598 Stack 2
Chip Position Top Chip Bottom Chip Top Chip Bottom Chip
ADD 0 n.c. VSS n.c. VSS
ADD 1 n.c. n.c. VSS VSS
C.S. n.c. n.c. n.c. n.c.
Active Bank Bank 0 Bank 1 Bank 2 Bank 3

Communication between the TMC0501E Enhanced Arithmetic Chip to the TMC0598 Multi-Register Chip is realized with multiple means:

• IDLE, CLK 1 and CLK 2 Outputs are used to synchronize all peripherals connected to the TMC0501E Enhanced Arithmetic Chip with the 16 States of its Instruction Cycle
• EXT Output indicates that the TMC0501E Enhanced Arithmetic Chip is addressing external memories/registers
• IRG Input to receive the 13-bit Instruction Words from the TMC0530/TMC0540/TMC0560/TMC0580 ROM Chips
• 4-bit bidirectional I/O Bus I/O 8, I/O 4, I/O 2, and I/O 1 to communicate with registers

QUICK-LINK to TMS0500 Family.

• Applications

TI-58, TI-59, TI-5230

Calculator Program steps Data memory TMC0599
TI-58 0-480 60-0 2
TI-59 160-960 100-0 4
TI-5230 t.b.d. t.b.d. 7

• Revisions

Revision Products First Prototypes Comments
TMC0598 SR-52 II (TI-59) November 1976 Initial design
Formerly TMC0599 Rev E

• Technical Specifications

Item Min Typ Max Unit Comments
VSS   0   V  
VDD -10.5 -10.0 -9.5 V  
PHI1, PHI2   225 230 kHz Opposite phases

• Technology

The TMC0598 is manufactured in a 7.5 um metal gate PMOS process (metal width = 0.30 mil / 7.5 um, metal spacing = 0.30 mil / 7.5 um, diffusion width = 0.25 mil / 6.0 um, diffusion spacing = 0.35 mil / 9.0 um).

The die size of the TMC0598 is approximately 210 mils * 140 mils / 5.3 mm * 3.6 mm.

• Packaging

The TMC0598 uses a standard 0.3” wide 16-pin DIP (Dual In-line Package with a 0.1” / 2.54 mm lead pitch).

• Pin Configuration

Pin IO Function Pin IO Function
1 V Negative Voltage VDD 16 I External access
2 I Calculating status 15 I CS (not connected)
3 I Clock Input 1 14 I SAMP (not connected)
4 I Clock Input 2 13 O Instruction words
5 IO SCOM Interface D0 12 I Bank-Select 1 (VSS, nc)
6 IO SCOM Interface D1 11 I Bank-Select 0 (VSS, nc)
7 IO SCOM Interface D2 10 IO SCOM Interface D3
8 V Common Voltage 9 V Negative Voltage VDD


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© Joerg Woerner, February 02, 2001. No reprints without written permission.