ATPL00B datasheet(26/152 Pages) ATMEL

26 / 152 page

Atmel ATPL00B [datasheet]

43028A-ATPL - 9/12

In the Lower 128 bytes of IDATA, the lowest 32 bytes are grouped into 4 banks of 8 registers. Program instructions call

out these registers as R0 through R7. Two bits in the Program Status Word (PSW) select which register bank is in use.

This allows more efficient use of code space, since register instructions are shorter than instructions that use direct

addressing.

The next 16 bytes above the register banks form a block of bit-addressable memory space. The 80C51 instruction set

includes a wide selection of single-bit instructions, and the 128 bits in this area can be directly addressed by these

instructions. The bit addresses in this area are 00H through 7FH.

Summarizing, the Lower 128 bytes are accessed independently of the addressing mode (direct or indirect addressing).

The Upper 128 bytes can be accessed only by indirect addressing, whereas SRF space is accessed only by direct

addressing.

Table 4-2 gives a look at the Special Function Register (SFR) space. SFRs include the Port registers, timers, peripheral

controls, etc. These registers can only be accessed by direct addressing. Sixteen addresses in SFR space are both

byte and bit addressable. The bit addressable SFRs are those whose address ends in 0H or 8H. ADD8051C3A includes

the same 21 SFRs included in the legacy 8051C plus additional SFRs to implement the extended features.

The CPU generates the RD (P3.7) and WR (P3.6) signals needed during SRAM accesses, as shown below.

4.3.4

SFR Registers

Table 4-2 shows a map of the internal memory area called the Special Function Register (SFR) space. The entries in

bold are registers not included in the standard architecture of the 8051, these entries are specific for the ADD8051C3A.

Blank entries are not implemented on the chip. User software should not write to these unimplemented locations. Read

accesses to these addresses will return random data

Table 4-2.

Special Function Registers (specific ADD8051C3A registers in bold)

@(Hex)

CONF

ACC

SPSTAT

SPCTL

SPDAT

SPSTAT1

SPCTL1

SPDAT10

SPDAT11

SPDAT12

SPDAT13

SPDAT14

SPDAT15

SPDAT16

SPDAT17

PSW

T2CON

T2MOD

RCAP2L

RCAP2H

TL2

TH2

IPH

IE2

AUX1

AUX2

SCON

SBUF

SCON1

SBUF1

P3M

P4M

P5M

IP2HL

SCON2

SBUF2

T1NP

TCON

TMOD

TL0

TL1

TH0

TH1

TPR

T1NC

DPL

DPH

PCON

ATPL00B Datasheet(PDF) 26 Page - ATMEL Corporation

ATPL00B Datasheet(HTML) 26 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL