Multiprocessor eliminates need for special input/output, memory,
or other interfaces devices
This microprocessor can reduce or eliminate problems associated with
interface, according to the manufacturer. Program memory may also be reduced.
The n-channel device, designated the 2650, requires a single +5 volt power supply
and is completely TTL compatible on all input/output pins, including the
single-phase TTL clock output. The interface structure of the 2650
eliminates the need for external level shifters, pull-up resistors, and
and/or latches, when connected to other TTL or NMOS devices.
The processor has a basic bus architecture with an 8-bit bidirectional data bus
and a separate 15-bit address bus. The fixed instruction set includes 75 arithmetic,
logical, branch, and control instructions. The processor has seven general-purpose
registers, a main arithmetic logic unit and a separate address adder, and eight-level
return address stack, and a BCD arithmetic capability.
Three input/output modes are provided, including a two-byte parallel mode, a
single-byte parallel mode, and a unique serial input/output mode using the flag
and sense lines. The serial mode is powerful in minimal system configurations
since it provides a means of performing serial computations under program control.
As a result, a low-cost interface can be designed for communicating with teletype
and other serial input devices without memory buffering or reformatting the data.
The 2650 also has a hardware vectored interrupt capability that can handle up to
64 different I/O devices.
The device has been designed using static logic only. Therefore, the clock can
be stopped in its low state for indefinite periods of time without any loss of
status or data currently on the chip.
The introductory price of the 2650 is $165 in single-unit quantities and under $100
for quantities exceeding 1000 units.
Contact Signetics, 811 East Arques Ave., Sunnyvale, Calif. 94086.