DS87C520/DS83C520 EPROM/ROM high speed microcontroller is a fast 8051 compatible microcontroller. They feature a redesigned processor core with no wasted clock or memory cycles. Thus, at the same crystal speed, every 8,051 instructions are executed 1.5 to 3 times faster than the original. Using the same code and the same crystals, a typical application will be 2.5 times faster.
Block Diagram
The DS87C520/DS83C520 provides a maximum crystal speed of 33MHz, resulting in an apparent execution speed of 82.5MHz (about 2.5 times). The DS87C520/DS83C520 is compatible with all three packages of the standard 8051 and includes standard resources such as three timers/counters, serial ports, and four 8-bit I/O ports. They have 16kB EPROM or mask ROM, plus 1kB of data RAM. Both OTP and window packages are available. In addition to faster speed, the microcontroller also includes a second all-hardware serial port, seven additional interrupts, programmable watchdog timer, outage monitor, and power failure reset.
The device also provides dual data Pointers (DPTRs) to speed up the movement of block data memory. It can also adjust the speed of MOVX data memory access from two to nine machine cycles for flexibility in selecting external memory and peripherals. A new power management mode (PMM) is very useful for portable applications. This feature allows the software to select a lower speed clock as the primary time base. A normal machine runs at 4 clocks per cycle, while the PMM runs the processor at 64 or 1024 clocks per cycle. For example, at 12MHz, the standard operating machine has a periodic rate of 3MHz.
In power management mode, the software can choose a machine cycle rate of 187.5kHz or 11.7kHz. Power consumption is reduced when the processor is running slower. EMI reduction allows the software to select reduced emission modes. This will disable the ALE signal when it is not needed.
