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Texas Instruments TMS1000

The TMS1000 is actually a series of 4-bit Microcontrollers containing ROM, RAM, I/O, & CPU on one chip produced by Texas Instruments. The units are not capable of expansion in any way. The highest clock frequency attainable by the series is 0.4MHz. This results in a 2.5 microsecond clock cycle. All instructions execute in 6 clock cycles. The devices were fabricated using PMOS and required a single -15V supply.

TMS1000The only data input available is through the 4 bit K input lines. Input instructions collect whatever signals are available on the input lines at the time. Output data exist as 8 O lines and 11, 13, or 16 control, or R lines. The accumulator and the status flag determine the bit pattern of the O lines. This information has to be requested when the chip is produced. What this means is that only 32 distinct patterns can be generated by the O lines. The Y register determines which individual R control line is being set or reset. All of these units have internal clock logic which can be connected to an RC circuit with one end of the capacitor connected to Vss, one end of the resistor connected to Vdd and the opposite ends of the components connected to both OSC1 and OSC2. If an externally generated signal is to be used, it must be connected to OSC1 while OSC2 is grounded. The INIT (reset signal) should be held high for at least 6 clock cycles after power is applied. Reset causes the Page Address and Page Buffer registers to be loaded with binary ones. The O and R outputs as well as the program counter are zeroed.

 

The TMS 1000 Family

TMS 1000 TMS 12000 TMS 1070 TMS 1270 TMS 1100 TMS 1300
Pin Count 28 40 28 40 28 40
ROM program Bytes 1024 1034 1024 1024 2048 2048
Ram Data 64 64 64 64 128 128
R signals Output 11 13 11 13 11 16
O Data Outputs  8  8  8  10  8  8

 

 

 


 

 

 

 

with permission of the author     www.datamath.org