S3C7044 Samsung semiconductor, S3C7044 Datasheet - Page 3

• Manufacturer Part Number: S3C7044
• Description: The S3C7044/C7048 single-chip CMOS microcontroller has been designed for very high-performance using Samsungs newest 4-bit CPU core/ SAM47 (Samsung Ar
• Manufacturer: Samsung semiconductor

S3C7044/C7048/P7048
FUNCTION OVERVIEW
SAM47 CPU
All S3C7-series microcontrollers have the advanced SAM47 CPU core. The SAM47 CPU can directly address up
to 32K-byte of program memory. The arithmetic logic unit(ALU) performs 4-bit addition, subtraction, logical, and
shift-and-rotate operations in one instruction cycle and most 8-bit arithmetic and logical operation in two cycles.
CPU REGISTERS
program counter
A 12-bit program counter (PC) stores addresses for instruction fetches during program execution. Usually, the PC
is incremented by the number of bytes of the fetched instruction. The one instruction fetch that does not
increment the PC is the 1-byte REF instruction which references instruction stored in a look-up table in the ROM.
Whenever a reset operation or an interrupt occurs, bits PC12 though PC0 are set to the vector address.
Stack pointer
An 8-bit stack pointer (SP) stores addresses for stack operation. The stack area is located in general-purpose
data memory bank 0. The SP is 8-bit read/writeable and SP bit 0 must always be logic zero.
During an interrupt or a subroutine call, the PC value and the PSW are written to the stack area. When the
service routine has completed, the values referenced by the stack pointer are restored. Then, the next instruction
is executed.
The stack pointer can access the stack despite data memory access enable flag status. Since the reset value of
the stack pointer is not defined in firmware, you use program code to initialize the stack pointer to 00H. This sets
the first register of the stack area to data memory location 0FFH.
PROGRAM MEMORY
In its standard configuration, the 4096 x 8-bit (S3C7404), 8192 x 8-bit (S3C7408) ROM is divided into four areas:
The vector address area is used mostly during reset operation and interrupts. These 16 bytes can alternately be
used as general-purpose ROM.
The REF instruction references 2x1-byte or 2-byte instruction stored in reference area location 0020H – 007FH.
REF can also reference three-byte instruction such as JP or CALL. So that a REF instruction can reference these
instruction, however, the JP or CALL must be shortened to a 2-byte format. To do this, JP or CALL is written to
the reference area with the format TJP or TCALL instead of the normal instruction name. Unused location in the
REF instruction look-up area can be allocated to general-purpose use.
16-byte area for vector addresses
96-byte instruction reference area
16-byte general-purpose area (0010 – 001FH)
3968-byte area for general-purpose program memory (S3C7404)
8064-byte area for general-purpose program memory (S3C7408)
PRODUCT OVERVIEW
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