TMP82C79P-2

The TMP82C79P-2(hereinafter referred to as TMP82C79) is a programmable keyboard/display interface. The keyboard portion can provide a scanned interface up to 64-contact key matrix.Also, the keyboard portion can interface to an array of sensors or a strobed interface keyboard.  Key depressions can be 2-key lockout or N-key rollover.The display portion has 16 X 8 bits display RAM which can be treated as dual 16 X 4 bits.Both right entry and left entry display formats are possible.

Features of the TMP82C79P-2 are:(1)simultaneous keyboard display operation; (2)scanned keyboard mode; (3)scanned sensor matrix mode; (4)strobed input entry mode; (5)Built-in 8-Character FIFO or 64 bit sensor RAM; (6)programmable 2-key lockout or N-key rollover with contact debounce; (7)built-in 16 X 8bit display RAM; (8)programmable scan timing; (9)extend operating temperature range -40 to+85.Return lines which are connected to the scan Iines through the key or sensor switches. Each line has an internal pullup to keep it high until a switch closure pulls it low. They also serve as an 8-bit input in Strobed Input mode.

The absolute maximum ratings of the TMP82C79P-2 can be summarized as:(1)Vcc supply voltage:-0.5 to 7.0V;(2)storage temperature range:-65 to 150;(3)input voltage:-0.5 to Vcc+0.5 V;(4)output voltage:-0.5 to Vcc+0.5 V;(5)soldering temperature:260;(6)power dissipation:250mW;(7)operating temperature range:-40 to 85.The TMP8279 generates alI timing and multiplexing signals by means of the internal prescaler.The prescaler generates internal reference clocks by dividing an external supply clock by a programmable value PPPPP. Any number from 2 to 31 can be set as a prescaler value. When this value is set to 0 or 1,it is interpreted to be 2. If the internal reference clock is set to 100kHz, it is possible to obtain 5.lms keyboard scan time and 10.3ms debounce time. The value PPPPP is set to 31 after reset, but cannot be changed by the Clear command.