TMP8253P-5

The TMP8253P-5 (hereinafter referred to as TMP8253) is a programmable counter/timer chip designed for use as the TLCS-85A microcomputer peripheral. It is organized as 3 independent 16 bit counters, each operates with a count rate of up to 2.6MHz. All modes of operation are software programmable.(The TMP8253P-5 contains logic that will allow the programmer to easily read the contents of any of the three counters without disturbing the actual count in progress. There are two methods that the programmer can use to read the value of the counters. The first method involves the use of simple I/O read operations. By controlling the A0, A1 inputs to the TMP8253P-5, the programmer can select the counter to be read. The only requirement with this method is that in order to assure a stable count reading the actual operation of the selected counter must be inhibited either by controlling the GATE input or by external logic that inhibits the clock input. The contents of the counter selected must be read in the sequence programmed in the Mode Control Word (RLO, RLI). When RLO, RL1 is 11. First I/O read contains the least significant byte second I/O read contains the most significant byte and the two bytes must be read before any loading WR command can be sent to the same counter. The second method allows the programmer to read the contents of any counter without affecting or disturbing the counting operation. When the programmer wishes to read the contents of a selected counter "On-the-fly", he loads the MODE register with a special code which latches the present count value into a storage register so that its contents contain an accurate, stable quantity. The programmer then issues a normal read command to the selected counter. The contents of the latched register must be read in the sequence programmed in the Mode Control Word (RLO, RLI). This commands has no effect on the counters mode.)

The features of TMP8253P-5 can be summarized as (1)count binary or BCD; (2)3 independent 16 bit counters; (3)single + 5V supply; (4)count rate DC to 2.6MHz; (5)6 programmable counter modes; (6)compatible with lntel's 8253-5.

The absolute maximum ratings of TMP8253P-5 are (1)VCC(Vcc supply voltage (with respect to Vss [GND]): -0.5 to +7V; (2)VIN(input voltage (with respect to Vss [GND]): -0.5 to Vcc+0.5V; (3)VOUT(output voltage (with respect to Vss [GND]):- 0.5 to Vcc + 0.5V; (4)PD(power dissipation): 1W; (5)Tsol(soldering temperature (sodlering time 10 sec)): 260°C; (6)Tstg(storage temperature):- 65 to +150°C; (7)Topr(operating temperature):0 to + 70°C.