Characterization of Single-chip Calculator Circuits - Other Devices

AMI S2144

The DCM-50A Platform supports the Characterization of the S2144 Device with the TMS1000 Textool Test Socket set to DCM-50A (TMS1000) mode and patching (swapping) most of the pins. One additional patch wire is needed to connect the external clock oscillator not available on the TMS1000 Socket but on the TMS0100 Socket or directly through the Digilent Digital Discovery Interface. The voltages V_SS and V_GG are set to 6.5V and -3.5V, respectively and V_DD is patched to the TMS0800 Socket.

Device-under-Test:

Keyboard: The Melcor Model 1000 makes use of a keyboard with 18 of its 20 switches arranged in an 9*2 matrix with the rows connected to the D1 to D9 Outputs (Display Scan) and the columns connected to the KN and KO Inputs (Keyboard Scan) of the S2144 single-chip calculator circuit. The [ON] and [OFF] keys are used with additional electronics to replace a traditional sliding switch.

Keyboard Matrix of the Melcor Model 1000:

Display: The Melcor Model 1000 makes use of an unknown Nine-Digit Calculator Numeric Seven-Segment LED Display module controlled with 2 additional SN75492-style digit drivers from the corresponding Output pins D1 to D9 and the segments SA to SDP driven directly from the S2144 chip.

Display Layout:

The Output Decoder of the S2144 is programmed for 7-Segment displays with the following Output Assignments:

Display Fonts:

Scanning: Display and keyboard scanning is performed in D1 → D9 direction at a rate of about 1,250 Hz with one Blank State after D9:

Mostek MK5020A

The DCM-50A Platform supports the Characterization of Mostek MK5020 Product Family Devices with the TMS1000 Textool Test Socket set to DCM-50A (TMS1000) mode and patching (swapping) most of the pins. One additional patch wire is needed to connect the Segment H output not available on the TMS1000 Socket but on the TMS0100 Socket and an additional "pull-down" resistor is necessary for the Clock Output pin of the MK5020 chip. The voltages V_SS and V_DD/V_GG are set to 9.5V and -5.5V, respectively. Alternatively the MK5020 chip can be placed in the TMS0100 Textool Test Socket set to DCM-50A (TMS0100) mode and Pin 14 isolated.

Device-under-Test:

Keyboard: The Heathkit IC-2006 makes use of a keyboard with 17 switches arranged in an 11*2 matrix with the rows connected to the D1-D11 Outputs (Display Scan) and the columns connected to the KN and KO Inputs (Keyboard Scan) of the MK5020A single-chip calculator circuit. The Constant/Chain sliding switch is connected between D10-KQ.

Keyboard Matrix of the Heathkit IC-2006:

Display: The Heathkit IC-2006 makes use of 3 National Semiconductor NSN33 Three-Digit Calculator Numeric Seven-Segment LED Displays mounted directly on the Main-PCB and controlled with 9 discrete digit drivers and 8 discrete segment drivers from the corresponding Output pins D1 to D9 and SA to SDP of the MK5020A chip with SH not connected.

Display Layout:

The Output Decoder PLA of the MK5020A is programmed for 7-Segment displays with the following Output Assignments:

Display Fonts:

Scanning: Display and keyboard scanning is performed in D11 → D1 direction at a rate of about 350 Hz:

TMS3707NC

The DCM-50A Platform supports the Characterization of the TMS3878 Five Decade Counter and the closely related TMS3707 with some supporting circuitry and the TMS1000 Textool Test Socket set to DCM-50A (TMS1000) mode. We added on a small breadboard a 10.24 MHz crystal oscillator with a 5-bit frequency divider to generate the 320 kHz time base clock of the TMS3707, a 6 MHz crystal oscillator with a 4-bit frequency divider to generate test frequencies between 375 kHz and 6 MHz, a 4-bit prescaler for the pulse input pin of the TMC3707 and a voltage regulator to generate the necessary V_DD voltage of -5V. The voltages V_SS and V_DD/V_GG at the TMS1000 Textool Test Socket are set to their lowest voltages of 5.5V and -3.0V, respectively.

Device-under-Test:

Keyboard: The TMS3707NC is in its known applications not connected to a keyboard.

Display: The Philips AM/FM car radios Coupé Digital 890 and 894 (22AC890, 22AC894) are using a green 3½-digit Sanyo SL-2405 LED display while the TMS3707 is supporting 5-digit LED displays.

Display Layout:

The Output Decoder PLA of the TMS3707 is programmed for 7-Segment displays with the following Output Assignments:

Display Fonts:

Scanning: Display scanning is performed in D1 → D5 direction with an Active Digit Time of 3.3 ms and a Blanking Time of 0.1 ms at a rate of about 60 Hz. The Segments A to G and the Decimal Point have an Active Segment Time of 2.4 ms and are activated in a staggered timing of 0.1 ms steps: