DATAMATH CALCULATOR MUSEUM
The MK502X is a programmable single-chip calculator which is both pin compatible and function compatible with the Texas Instruments one-chip calculator circuit TMS0102. Improved features are available from the MK502X, including:
• Lower power
• Single supply operation
• Broader supply voltage operating range
• Internal clock oscillator
• More extensive programmability
The first four functions above were made possible through the use of MOSTEK's ion-implantation, depletion-mode load, P-channel MOS process. These features make the MK502X ideal for battery operated hand-held calculators where battery life and calculator compactness are prime considerations. The more extensive programmability of the MK502X allows implementation of complex special functions through custom programming.
Due to a flexible design concept with both programmable PLA and ROM techniques a lot of design variations appeared. These include different types of the key-matrix, 8 or 10 digits of 7- or 8-segmented outputs. The two letters behind the product designation define the ROM-code (A,B,C...) and package (P for ceramic housing).
A typical calculator built around the MK502X family performs the four basic functions +, -, *, and : with either Constant or Chain operation. The calculations are done on a floating decimal-point operation but the display of the results could be selected between the floating-point or a fixed-point format. The keyboard scanning, debouncing and encoding in performed inside the chip. The display outputs are fully decoded with a leading zero suppression and multiplexed.
|CK||182||kHz||200kOhm and 36pF|
The MK502X P uses a 0.6” wide 28-pin CDIP or DIP (Ceramic Dual In-line Package or Dual In-line Package with a 0.1” / 2.54 mm lead pitch).
|1||I||Clock Input||28||V||Common Voltage|
|2||I||Keymatrix input P||27||I||Keymatrix input Q|
|3||O||Digit driver 1 (LSD)||26||I||Keymatrix input N|
|4||O||Digit driver 2||25||I||Keymatrix input O|
|5||O||Digit driver 3||24||O||Segment driver DP|
|6||O||Digit driver 4||23||O||Segment driver H|
|7||O||Digit driver 5||22||O||Segment driver G|
|8||O||Digit driver 6||21||O||Segment driver F|
|9||O||Digit driver 7||20||O||Segment driver E|
|10||O||Digit driver 8 (MSD8)||19||O||Segment driver D|
|11||O||Digit driver 9||18||O||Segment driver C|
|12||O||Digit driver 10 (MSD10)||17||O||Segment driver B|
|13||O||Digit driver 11 (OVER)||16||O||Segment driver A|
|14||T||Test input||15||V||Negative Voltage VGG|
|The Segment drivers A-H and the Decimal point are connected to a display in the pictured way.|
The keyboards of all calculators based on the MK502X family consist of a x/y-matrix connected to the digit driver outputs D1-D11 and the keymatrix inputs KN and KO. In the fixed-point output format mode the position of the decimal point is selected with the KP input. The Constant/Chain switch is connected between D10-KQ.
|D7||7||+/-||DP7||RND up||D7||7||+/-||DP7||RND up|
|D9||9||.||RND dwn||D9||9||.||DP9||RND dwn|
Calculators based on the MK502X use normally LED displays. Texas Instruments introduced together with their calculator chips two pre-configured LED-modules (DIS40, DIS95) based on the TIL360 arrays, the corresponding segment drivers (SN75491) and digit drivers (SN75492). Most designs make use of these parts.
If you have additions to the above datasheet please email: firstname.lastname@example.org.
© Joerg Woerner, February 02, 2001. No reprints
without written permission.