Maxim Integrated High-Speed Microcontroller - Manual (Page 9)

High-Speed Microcontroller User’s Guide
Rev: 062210 9 of 176
1. INTRODUCTION
Maxim high-speed microcontrollers are 8051-compatible devices that provide improved performance and
power consumption compared to the original version. They retain instruction-set and object-code
compatibility with the 8051, yet perform the same operations in fewer clock cycles. Consequently, more
throughput is possible for the same crystal speed. As an alternative, the high-speed microcontroller’s
more efficient design allows a much slower crystal speed to get the same results as an original 8051,
using much less power.
The fundamental innovation of the high-speed microcontroller is the use of only four clocks per
instruction cycle compared with 12 for the original 8051. This results in up to three times improvement in
performance. In addition, the high-speed microcontroller is updated with several new peripherals and
features while providing all of the standard features of an 80C32. These include 256 bytes of on-chip
RAM for variables and stack, 32 I/O ports, three 16-bit timer/counters, and an on-chip UART.
In addition to improved efficiency, most devices can operate at a maximum clock rate of 33MHz or
40MHz. Combined with the three times performance, this allows for a maximum performance equivalent
to a 99MHz or 120MHz 8051. This level of computing power is comparable to many 16-bit processors,
but without the added expense.
A number of peripherals were added to the original 80C32 core. Some devices have a programmable
watchdog timer to supervise the system. It counts up to a user programmable interval and then reset the
CPU unless cleared by software. Other features such as a second, full-function UART and dual data
pointers are available to minimize external interrupts allows greater flexibility in dealing with external
events.
Some devices incorporate power management modes that allow the device to dynamically vary the
internal clock speed from 4 clocks per cycle (default) to 64 or 1024 clocks per cycle. Because power
consumption is directly proportional to clock speed, the device can reduce its operating frequency during
periods of little or no activity. This greatly reduces power consumption. The switchback feature allows
the device to quickly return in divide-by-4 mode upon receipt of an interrupt or serial port activity,
allowing the device to respond to external events while in power management mode.
Various memory configurations are available with the high-speed microcontroller family. EPROM and
Mask programmable ROM versions are available for program memory. Some versions incorporate
extended MOVX SRAM on-chip, reducing or eliminating the need for external data memory. This
memory can be made nonvolatile in the DS87C530 through the use of an external lithium battery.
Note: Information contained in specific data sheets supersedes general information found in this user’s
guide. Designers are cautioned to obtain and read carefully the data sheets, this user’s guide, and any
relevant supplements before using any Maxim microcontroller.