C8051F060DK Silicon Laboratories Inc, C8051F060DK Datasheet - Page 131

• Manufacturer Part Number: C8051F060DK
• Description: DEV KIT FOR F060/F062/F063
• Manufacturer: Silicon Laboratories Inc
• Type: MCUr

Specifications of C8051F060DK

• Contents: Evaluation Board, Power Supply, USB Cables, Adapter and Documentation
• Processor To Be Evaluated: C8051F06x
• Interface Type: USB
• Silicon Manufacturer: Silicon Labs
• Core Architecture: 8051
• Silicon Core Number: C8051F060
• Silicon Family Name: C8051F06x
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With/related Products: C8051060, C8051F062 and C8051F063
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 336-1214

C8051F060/1/2/3/4/5/6/7
13.2.2. Data Memory
The CIP-51 implements 256 bytes of internal RAM mapped into the data memory space from 0x00 through
0xFF. The lower 128 bytes of data memory are used for general purpose registers and scratch pad mem-
ory. Either direct or indirect addressing may be used to access the lower 128 bytes of data memory. Loca-
tions 0x00 through 0x1F are addressable as four banks of general purpose registers, each bank consisting
of eight byte-wide registers. The next 16 bytes, locations 0x20 through 0x2F, may either be addressed as
bytes or as 128 bit locations accessible with the direct addressing mode.
The upper 128 bytes of data memory are accessible only by indirect addressing. This region occupies the
same address space as the Special Function Registers (SFRs) but is physically separate from the SFR
space. The addressing mode used by an instruction when accessing locations above 0x7F determines
whether the CPU accesses the upper 128 bytes of data memory space or the SFRs. Instructions that use
direct addressing above 0x7F will access the SFR space. Instructions using indirect addressing above
0x7F access the upper 128 bytes of data memory. Figure 13.2 illustrates the data memory organization of
the CIP-51.
13.2.3. General Purpose Registers
The lower 32 bytes of data memory, locations 0x00 through 0x1F, may be addressed as four banks of gen-
eral-purpose registers. Each bank consists of eight byte-wide registers designated R0 through R7. Only
one of these banks may be enabled at a time. Two bits in the program status word, RS0 (PSW.3) and RS1
(PSW.4), select the active register bank (see description of the PSW in Figure 13.16). This allows fast con-
text switching when entering subroutines and interrupt service routines. Indirect addressing modes use
registers R0 and R1 as index registers.
13.2.4. Bit Addressable Locations
In addition to direct access to data memory organized as bytes, the sixteen data memory locations at 0x20
through 0x2F are also accessible as 128 individually addressable bits. Each bit has a bit address from
0x00 to 0x7F. Bit 0 of the byte at 0x20 has bit address 0x00 while bit 7 of the byte at 0x20 has bit address
0x07. Bit 7 of the byte at 0x2F has bit address 0x7F. A bit access is distinguished from a full byte access by
the type of instruction used (a bit source or destination operand as opposed to a byte source or destina-
tion).
The MCS-51™ assembly language allows an alternate notation for bit addressing of the form XX.B where
XX is the byte address and B is the bit position within the byte. For example, the instruction:
MOV
C, 22.3h
moves the Boolean value at 0x13 (bit 3 of the byte at location 0x22) into the Carry flag.
13.2.5. Stack
A programmer's stack can be located anywhere in the 256 byte data memory. The stack area is designated
using the Stack Pointer (SP, address 0x81) SFR. The SP will point to the last location used. The next value
pushed on the stack is placed at SP+1 and then SP is incremented. A reset initializes the stack pointer to
location 0x07; therefore, the first value pushed on the stack is placed at location 0x08, which is also the
first register (R0) of register bank 1. Thus, if more than one register bank is to be used, the SP should be
initialized to a location in the data memory not being used for data storage. The stack depth can extend up
to 256 bytes.
The MCUs also have built-in hardware for a stack record which is accessed by the debug logic. The stack
record is a 32-bit shift register, where each PUSH or increment SP pushes one record bit onto the register,
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