ST10F276 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST10F276' PDF : 229 Pages View PDF
ST10F276
6
Central processing unit (CPU)
Central processing unit (CPU)
The CPU includes a 4-stage instruction pipeline, a 16-bit arithmetic and logic unit (ALU) and
dedicated SFRs. Additional hardware has been added for a separate multiply and divide
unit, a bit-mask generator and a barrel shifter.
Most of the ST10F276’s instructions can be executed in one instruction cycle which requires
31.25ns at 64 MHz CPU clock. For example, shift and rotate instructions are processed in
one instruction cycle independent of the number of bits to be shifted.
Multiple-cycle instructions have been optimized: branches are carried out in 2 cycles, 16 x
16-bit multiplication in 5 cycles and a 32/16-bit division in 10 cycles.
The jump cache reduces the execution time of repeatedly performed jumps in a loop, from
2 cycles to 1 cycle.
The CPU uses a bank of 16 word registers to run the current context. This bank of General
Purpose Registers (GPR) is physically stored within the on-chip Internal RAM (IRAM) 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, a register bank may overlap others.
A system stack of up to 2048 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 implicitly compared against the stack pointer
value upon each stack access for the detection of a stack overflow or underflow.
Figure 14. CPU Block Diagram (MAC Unit not included)
512 Kbyte
Flash
memory
32
SP
STKOV
STKUN
Exec. Unit
Instr. Ptr
4-Stage
Pipeline
PSW
SYSCON
BUSCON 0
BUSCON 1
BUSCON 2
BUSCON 3
BUSCON 4
Data Pg. Ptrs
CPU
MDH
MDL
Mul./Div.-HW
Bit-Mask Gen.
ALU
16-Bit
Barrel-Shift
CP
ADDRSEL 1
ADDRSEL 2
ADDRSEL 3
ADDRSEL 4
Code Seg. Ptr.
R15
General
Purpose
Registers
R0
16
2 Kbyte
Internal
RAM
Bank
n
Bank
i
Bank
16
0
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