TK87C751 Microcontroller, 64K Flash

Features

8 Bit Microcontroller with 8051 architecture 64Kx8 Internal Flash ROM (2Kx8 in original) 128 bytes of Internal RAM (64 bytes in original) Low standby current at full supply voltage 0-20 MHz operation Classic architecture instruction timing 3 Bidirectional ports (19 bits) 28 pin PLCC package Built in power management Two Wire Interface (TWI) (I2CTM compatible) 16 bit Timer/Counter with auto-reload. Fixed rate Timer LED compatible outputs Direct replacement for Philips S83C751 / S87C751 microprocessors. Implemented with the Tekmos Customer Configured Microprocessor (CCM) technology

General Description

The TK87C751 is a derivative of the 8051 microprocessor architecture.  With 64Kx8 of Flash ROM, and 128x8 of scratchpad RAM, this part is a pin-for-pin replacement of the Philips 87C751 microprocessor.

The TK87C751 is intended to provide the 80C51 architecture in a small package and with a hardware Two Wire Interface (TWI).  The integrated TWI interface allows the TK83C751 or operate as either a master or a slave on the TWI bus.

To achieve this, port P2, and 5 bits of port P0 were removed, along with the external bus control pins.  This allows the TK83C751 to fit within either a 24 pin, 300 mil PDIP package, or a 28 pin PLCC package.

The 8051 architecture has been modified to provide a Two-Wire Interface (TWI).  Starting with the basic 80C51 design, the serial port and the two timers in the 80C51 were removed and replaced with the TWI interface and its associated timers.  The external interrupt pins and the timer gate and count pins were relocated from port P3 to port P1. The interrupt controller was simplified to provide only a single set of priorities.

The ability of the design to access external program and data memory was also removed, along with the PSEN, ALE, and EA pins.

The TK87C751 is built utilizing the Tekmos Customer Configured Microprocessor (CCM) technology.  Refer to the CCM data sheet for details on creating other microprocessors.

Ordering

The TK87C751 is FLASH programmed and may be ordered directly from Tekmos in quantities as low as 1 unit.

Tekmos will program the parts on request.

Please note that the TK87C751 is only available in the 28 pin PLCC version.  Die size restrictions prevent us from offering it in the 24 pin, 300 mil PDIP package.  We expect to offer the TK87C751 in a 24 pin DIP package early in 2008.  Tekmos does provide the TK83C751 masked ROM version in the 24 pin DIP package.

Documentation

The data sheet is available here.

Differences with the NXP Part

The TK87C751 is available in the 28 PLCC only.

We are offering a 24 pin version that is built using a 28 pin device on a daughtercard.  The daughtercard is 19/32" wide (15.5mm) by 1 7/32" long (30.5mm).  The overhang of the daughtercard may prevent this from being used in all applications.  The PDIP24 package is currently available in the ROM version only.  We expect to have a 24 pin version available in Q2 of 2008.

The Tekmos TK87C751 does not have the security bits that prevent the reading of the ROM code.