ST10R272L STMicroelectronics, ST10R272L Datasheet - Page 13

• Manufacturer Part Number: ST10R272L
• Description: 16-BIT Romless MCU WITH MAC UNIT
• Manufacturer: STMicroelectronics

Specifications of ST10R272L

• Cpu Frequency: 0 to 50 MHz
• Power: 3.3 Volt +/-0.3V

4
The main core of the CPU contains a 4-stage instruction pipeline, a MAC multiply-
accumulation unit, a separate multiply and divide unit, a bit-mask generator and a barrel
shifter. Most instructions can be executed in one machine cycle requiring 40ns at 50MHz CPU
clock.
The CPU includes an actual register context consisting of 16 wordwide GPRs physically
located in the on-chip RAM area. A Context Pointer (CP) register determines the base
address of the active register bank to be accessed by the CPU. The number of register banks
is only restricted by the available internal RAM space. For easy parameter passing, one
register bank may overlap others.
A system stack of up to 1024 bytes is provided as a storage for temporary data. The system
stack is allocated in the on-chip RAM area, and it is accessed by the CPU via the stack pointer
(SP) register. Two separate SFRs, STKOV and STKUN, are compared against the stack
pointer value during each stack access to detect stack overflow or underflow.
CENTRAL PROCESSING UNIT
Data Pg. Ptrs
BUSCON 0
BUSCON 1
BUSCON 2
BUSCON 3
BUSCON 4
SYSCON
Exec. Unit
Instr. Ptr
Instr. Reg
PSW
STKOV
STKUN
4-Stage
Pipeline
SP
Figure 4 CPU block diagram
ADDRSEL 1
ADDRSEL 2
ADDRSEL 3
ADDRSEL 4
Code Seg. Ptr.
Bit-Mask Gen.
Mul./Div.-HW
Context Ptr
Barrel-Shift
CPU
16-Bit
MDH
MDL
ALU
ST10R272L - CENTRAL PROCESSING UNIT
IDX0
QR0
QX0
Registers
Purpose
General
R15
R0
QR1
IDX1
QX1
16
16
1KByte
Internal
RAM
R15
R0
13/77
1