UPSD33XX Datasheet, PDF (21/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

MCU MODULE DISCRIPTION
This section provides a detail description of the
MCU Module system functions and peripherals, in-
cluding:
■ 8032 MCU Registers
■ Special Function Registers
■ 8032 Addressing Modes
■ uPSD33xx Instruction Set Summary
■ Dual Data Pointers
■ Debug Unit
■ Interrupt System
■ MCU Clock Generation
■ Power Saving Modes
■ Oscillator and External Components
uPSD33xx
■ I/O Ports
■ MCU Bus Interface
■ Supervisory Functions
■ Standard 8032 Timer/Counters
■ Serial UART Interfaces
■ IrDA Interface
■ I²C Interface
■ SPI Interface
■ Analog to Digital Converter
■ Programmable Counter Array (PCA)
Note: A full description of the 8032 instruction set
may be found in the uPSD33xx Programmers
Guide.
8032 MCU REGISTERS
The uPSD33xx has the following 8032 MCU core
registers, also shown in Figure 11.
Figure 11. 8032 MCU Registers
PCH
DPTR(DPH)
A
B
SP
PCL
PSW
R0-R7
DPTR(DPL)
Accumulator
B Register
Stack Pointer
Program Counter
Program Status Word
General Purpose
Register (Bank0-3)
Data Pointer Register
AI06636
Stack Pointer (SP)
The SP is an 8-bit register which holds the current
location of the top of the stack. It is incremented
before a value is pushed onto the stack, and dec-
remented after a value is popped off the stack. The
SP is initialized to 07h after reset. This causes the
stack to begin at location 08h (top of stack). To
avoid overlapping conflicts, the user must initialize
the top of the stack to 20h if all four banks of reg-
isters R0 - R7 are used, and the user must initialize
the top of stack to 30h if all of the 8032 bit memory
locations are used.
Data Pointer (DPTR)
DPTR is a 16-bit register consisting of two 8-bit
registers, DPL and DPH. The DPTR Register is
used as a base register to create an address for in-
direct jumps, table look-up operations, and for ex-
ternal data transfers (XDATA). When not used for
addressing, the DPTR Register can be used as a
general purpose 16-bit data register.
Very frequently, the DPTR Register is used to ac-
cess XDATA using the External Direct addressing
mode. The uPSD33xx has a special set of SFR
registers (DPTC, DPTM) to control a secondary
DPTR Register to speed memory-to-memory
XDATA transfers. Having dual DPTR Registers al-
lows rapid switching between source and destina-
tion addresses (see details in DUAL DATA
POINTERS, page 37).
Program Counter (PC)
The PC is a 16-bit register consisting of two 8-bit
registers, PCL and PCH. This counter indicates
the address of the next instruction in program
memory to be fetched and executed. A reset forc-
es the PC to location 0000h, which is where the re-
set jump vector is stored.
Accumulator (ACC)
This is an 8-bit general purpose register which
holds a source operand and receives the result of
arithmetic operations. The ACC Register can also
be the source or destination of logic and data
movement operations. For MUL and DIV instruc-
tions, ACC is combined with the B Register to hold
16-bit operands. The ACC is referred to as “A” in
the MCU instruction set.
B Register (B)
The B Register is a general purpose 8-bit register
for temporary data storage and also used as a 16-
bit register when concatenated with the ACC Reg-
ister for use with MUL and DIV instructions.
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