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Extended Interrupt Enable (EIE), Extended

Interrupt priority (EIP) and (TCON) registers.

I/O Ports

– Block contains 8051’s general pur-

pose I/O ports. Each of port’s pin can be

read/write as a single bit or as an 8-bit bus

called P0, P1, P2, P3.

Power Management Unit

– Block contains

advanced power saving mechanisms with

switchback feature, allowing external clock

control logic to stop clocking (Stop mode) or

run core in lower clock frequency (Power Man-

agement Mode) to significantly reduce power

consumption.

Switchback

feature

allows

UARTs, and interrupts to be processed in full

speed mode if enabled. It is very desired when

microcontroller is planned to use in portable

and power critical applications.

DoCD™ Debug Unit

– it’s a real-time hard-

ware debugger provides debugging capability

of a whole SoC system. In contrast to other on-

chip debuggers DoCD™ provides non-intrusive

debugging of running application. It can halt,

run, step into or skip an instruction, read/write

any contents of microcontroller including all

registers, internal, external, program memo-

ries, all SFRs including user defined peripher-

als. Hardware breakpoints can be set and con-

trolled on program memory, internal and exter-

nal data memories, as well as on SFRs. Hard-

ware breakpoint is executed if any write/read

occurred at particular address with certain data

pattern or without pattern. Two additional pins

CODERUN, DEBUGACS indicate the sate of

the debugger and CPU. CODERUN is active

when CPU is executing an instruction. DE-

BUGACS pin is active when any access is per-

formed by DoCD™ debugger. The DoCD™

system includes JTAG interface and complete

set of tools to communicate and work with core

in real time debugging. It is built as scalable

unit and some features can be turned off to

save silicon and reduce power consumption. A

special care on power consumption has been

taken, and when debugger is not used it is

automatically switched in power save mode.

Finally whole debugger is turned off when de-

bug option is no longer used.

Floating Point Unit

– Block contains floating

point arithmetic IEEE-754 compliant instruc-

tions (C float, int, long int types supported). It

is used to execute single precision floating

point operations such as: addition, subtraction,

multiplication, division, square root, compari-

son absolute value of number and change of

sign. Basing on specialized CORDIC algorithm

a full set of trigonometric operations are also

allowed: sine, cosine, tangent, arctangent. It

also has built-in integer to floating point and

vice versa conversion instructions. FPU sup-

ports single precision real numbers, 16-bit and

32-bit signed integers. This unit has included

standard software interface allows easy usage

and interfacing with user C/ASM written pro-

grams.

MDU32 Multiply Divide Unit

– It’s a fixed

point fast 16-bit and 32-bit multiplication and

division unit. It supports unsigned and 2’s

complement signed integer operands. The

MDU32 is controlled by dedicated direct mem-

ory access module (called DMA). All argu-

ments and result registers are automatically

read and written back by internal DMA. This

unit has included standard software interface

allows easy usage and interfacing with user

C/ASM written programs. This module is re-

placement of older MDU.

Timers

– System timers module. Contains two

16 bits configurable timers: Timer 0 (TH0,

TL0), Timer 1 (TH1, TL1) and Timers Mode

(TMOD) registers. In the timer mode, timer

registers are incremented every 12 CLK peri-

ods when appropriate timer is enabled. In the

counter mode the timer registers are incre-

mented every falling transition on their corre-

sponding input pins (T0, T1), if gates are

opened (GATE0, GATE1). T0, T1 input pins

are sampled every CLK period. It can be used

as clock source for UARTs.

Timer 2

– Second system timer module con-

tains one 16-bit configurable timer: Timer 2

(TH2, TL2), capture registers (RLDH, RLDL)

and Timer 2 Mode (T2MOD) register. It can

work as a 16-bit timer / counter, 16-bit auto-

reload timer / counter. It also supports com-

pare capture unit if it’s presented in system. It

can be used as clock source for UART0.

Compare Capture Unit

– The compare / cap-

ture / reload unit is one of the most powerful

peripheral units of the core. It can be used for

all kinds of digital signal generation and event

capturing such as pulse generation, pulse

width modulation, measurements etc.

Watchdog Timer

– The watchdog timer is a

27-bit counter which is incremented every sys-

tem clock periods (CLK pin). It performs sys-

tem protection against software upsets.