C500 Architecture and Instruction Set

U s e r ’s M a n u a l, J u l y 2 0 0 0
C500
Architecture and Instruction Set
Microcontrollers
N e v e r
s t o p
t h i n k i n g .
Edition 2000-07
Published by Infineon Technologies AG,
St.-Martin-Strasse 53,
D-81541 München, Germany
© Infineon Technologies AG 2000.
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U s e r ’s M a n u a l, J u l y 2 0 0 0
C500
Architecture and Instruction Set
Microcontrollers
N e v e r
s t o p
t h i n k i n g .
C500 Architecture and Instruction Set User’s Manual
Revision History:
2000-07
Previous Version:
1998-04
Page
Subjects (major changes since last revision)
–
Section on Package Information removed.
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C500
Table of Contents
Page
1
1.1
1.2
1.2.1
1.2.2
1.2.2.1
1.2.2.2
1.2.2.3
1.2.3
Fundamental Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Memory Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Program Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Internal Data Memory XRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
External Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Special Function Register Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
2.1
2.2
2.3
2.4
2.5
2.5.1
2.5.2
2.5.3
2.5.4
2.6
2.7
2.8
CPU Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
B Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Program Status Word . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Stack Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Data Pointer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
The Importance of Additional Datapointers . . . . . . . . . . . . . . . . . . . . . 2-5
How the eight Datapointers of the C500 are Realized . . . . . . . . . . . . . 2-5
Advantages of Multiple Datapointers . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Application Example and Performance Analysis . . . . . . . . . . . . . . . . . 2-6
Enhanced Hooks Emulation Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Basic Interrupt Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Interrupt Response Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12
3
3.1
3.2
3.2.1
3.2.2
CPU Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Basic Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing External Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing External Program Memory . . . . . . . . . . . . . . . . . . . . . . . . .
Accessing External Data Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.3
4.4
4.4.1
4.4.2
Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Addressing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Introduction to the Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Data Transfer Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Arithmetic Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Logic Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Control Transfer Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Instruction Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8
Instruction Set Summary Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-82
Functional Groups of Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-82
Hexadecimal Ordered Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . 4-86
User’s Manual
I-1
1-1
1-1
1-2
1-2
1-3
1-3
1-5
1-6
1-6
3-1
3-1
3-3
3-3
3-4
2000-07
C500
Fundamental Structure
1
Fundamental Structure
1.1
Introduction
The members of the C500 Infineon Technologies microcontroller family are basically
fully compatible in architecture and software to the standard 8051 microcontroller family.
Especially, they are functionally upward compatible to the SAB 80C52/80C32
microcontroller. While maintaining all architectural and operational characteristics of the
SAB 80C52/80C32, the C500 microcontrollers differ in number and complexity of their
peripheral units which have been adapted to the specific application areas.
The goal of this “Architecture and Instruction Set Manual” is to summarize the basic
architecture and functional characteristics of all members of the C500 microcontroller
family. This includes the description of the architecture and the description of the
complete instruction set. Detailed information about the different versions of the C500
microcontrollers are given in the specific User Manuals.
User’s Manual
1-1
2000-07
C500
Fundamental Structure
1.2
Memory Organization
The memory resources of the C500 family microcontrollers are organized in different
types of memories (data and program memory), which further can be located internally
on the microcontroller chip or outside of the microcontroller. The memory partitioning of
the C500 microcontrollers is typical for a Harvard architecture where data and program
areas are held in separate memory areas. The on-chip peripheral units are accessed
using an internal special function register memory area.
The available memory areas have different sizes and are located in the following five
address spaces:
Table 1-1
C500 Address Spaces
Type of Memory
Location
Size
Program Memory
External
max. 64 KByte
Internal (ROM,
EEPROM)
Depending on C500 version
2K up to 64 KByte
External
max. 64 KByte
Internal XRAM
Depending on C500 version
256 Byte up to 3 KByte
Internal
128 or 256 Byte
Internal
128/256 Bytes
Data Memory
Special Function Register
1.2.1
Program Memory
The program memory of the C500 family microcontrollers can be composed of either
completely external program memory, of only internal program memory (on-chip ROM/
EEPROM), or of a mixture of internal and external program memory. lf the EA pin
(EA = External Access) is held at low level, the C500 microcontrollers execute the
program code always out of the external program memory. Romless C500 derivatives
can use this type of program memory only. C500 derivatives with on-chip program
memory typically use their internal program memory only. If the internal program
memory is used the EA pin must be put to high level. With EA high, the microcontroller
executes instructions internally unless the address exceeds the upper limit of the internal
program memory. If the program counter is set to an address (e.g. by a jump instruction)
which is higher than the internal program memory, instructions are executed out of an
external program memory. When the instruction address again is below the internal
program memory size limit, internal program memory is accessed again.
Figure 1-1 shows the typical C500 family microcontroller program memory configuration
for the two cases EA = 0 and EA = 1. The ROM boundary shown in Figure 1-1, applies
to the C501 which has 8 Kbyte of internal ROM. Other C500 family microcontrollers with
different ROM size have different ROM boundaries.
User’s Manual
1-2
2000-07
C500
Fundamental Structure
EA = 1
EA = 0
FFFF H
FFFF H
External
Program
Memory
2000 H
1FFF H
0000 H
Internal
Program
Memory
External
Program
Memory
ROM
Boundary
0000 H
The location of the ROM boundary depends on the specific C500 devices.
MCD02766
Figure 1-1
1.2.2
Program Memory Configuration (Example of the C501)
Data Memory
The data memory area of the C500 family microcontrollers consists of internal and
external data memory portions. The internal data memory area is addressed using 8-bit
addresses. The external data memory and the internal XRAM data memory are
addressed by 8-bit or16-bit addresses.
The content of the internal data memory (also XRAM) is not affected by a reset
operation. After power-up the content is undefined, while it remains unchanged during
and after a reset as long as the power supply is not turned off. The XRAM content is also
maintained when the C500 microcontrollers are in power saving modes.
1.2.2.1
Internal Data Memory
The internal data memory address space is divided into three basic, physically separate
and distinct blocks: the lower 128 byte of internal data RAM, the upper 128 byte of
internal data RAM, and the 128 byte special function register (SFR) area. The lower
internal data RAM and the SFR area further include 128 bit locations each. These bits
can be handled by specific bit manipulation instructions.
User’s Manual
1-3
2000-07
C500
Fundamental Structure
Figure 1-2 shows the configuration of the three basic internal RAM areas. The lower
data RAM is located in the address range 00H - 7FH and can be addressed directly (e.g.
MOV A, direct) or indirectly (e.g. MOV A, @R0 with address in R0). A bit-addressable
area of 128 free programmable, direct addressable bits is located at byte addresses 20H
- 2FH of the lower data RAM. Bit 0 of the internal data byte at 20H has the bit address
00H while bit 7 of the internal data byte at 2FH has the bit address 7FH. The lower
32 locations of the internal lower data RAM are assigned to four banks with eight general
purpose registers (GPRs) each. Only one of these banks can be enabled at a time to be
used as general purpose registers.
FF H
7F H
E8 H EF EE ED EC EB EA E9 E8
1)
(indirect
addressable)
E0 H E7 E6 E5 E4 E3 E2 E1 E0
128 Byte
D8 H DF DE DD DC DB DA D9 D8
D0 H D7 D6 D5 D4 D3 D2 D1 D0
80 H
7F H
C8 H CF CE CD CC CB CA C9 C8
C0 H C7 C6 C5 C4 C3 C2 C1 C0
Lower
Internal Data
RAM
B8 H BF BE BD BC BB BA B9 B8
(indirect & direct
addressable)
B0 H B7 B6 B5 B4 B3 B2 B1 B0
128 Byte
A8 H AF AE AD AB AC AA A8 A9
00 H
A0 H A7 A6 A5 A4 A3 A2 A1 A0
98 H 9F 9E 9D 9B 9C 9A 98 99
90 H 97 96 95 94 93 92 91 90
88 H 8F 8E 8D 8B 8C 8A 88 89
80 H 87 86 85 84 83 82 81 80
Internal SFR Area
(direct addressable)
128 Byte
1) This internal RAM area is optional. Some low-end C500 family microcontrollers don’t
provide this internal RAM area.
Figure 1-2
User’s Manual
~
~
~
~
RAM Area
30 H
2F H
2E H
2D H
2C H
2B H
2A H
29 H
28 H
27 H
26 H
25 H
24 H
23 H
22 H
21 H
20 H
1F H
18 H
17 H
10 H
0F H
08 H
07 H
06 H
05 H
04 H
03 H
02 H
01 H
00 H
7F
77
6F
67
5F
57
4F
47
3F
37
2F
27
1F
17
0F
07
7E
76
6E
66
5E
56
4E
46
3E
36
2E
26
1E
16
0E
06
7D
75
6D
65
5D
55
4D
45
3D
35
2D
25
1D
15
0D
05
7C
74
6C
64
5C
54
4C
44
3C
34
2C
24
1C
14
0C
04
3B
73
6B
63
5B
53
4B
43
3B
33
2B
23
1B
13
0B
03
7A
72
6A
62
5A
52
4A
42
3A
32
2A
22
1A
12
0A
02
79
71
69
61
59
51
49
41
39
31
29
21
19
11
09
01
78
70
68
60
58
50
48
40
38
30
28
20
18
10
08
00
16 Bytes with 128 bitaddressable Bits
F0 H F7 F6 F5 F4 F3 F2 F1 F0
Upper
Internal Data
RAM
Registerbank 3
Registerbank 2
Registerbank 1
R7
R6
R5
R4
R3
R2
R1
R0
Registerbank 0
FF H
F8 H FF FE FD FC FB FA F9 F8
MCD02767
Internal Data Memory Organization
1-4
2000-07
C500
Fundamental Structure
While the SFR area and the upper internal RAM area share the same address locations
(80H - F8H), they must be accessed through different addressing modes. The upper
internal RAM can only be accessed through indirect addressing while the special
function registers (SFRs) are accessible only by direct addressing instructions. The
SFRs which are located at addresses with address bit 0-2 equal 0 (addresses 80 H, 88H,
90H, … F0H, F8H) are bitaddressable SFRs.
1.2.2.2
Internal Data Memory XRAM
Some members of the C500 family microcontrollers provide an additional internal data
memory area, called the XRAM. This data memory area is logically located at the upper
end of the external data memory space (except C502), but it is integrated on the chip.
Because the XRAM is used in the same way as external data memory the same
instruction types must be used for accessing the XRAM.
Figure 1-3 shows a typical 256 byte XRAM address mapping of the C500
microcontrollers.
FFFF H
Internal
XRAM
FFFF H
FF00 H
FEFF H
External
Data
Memory
0000 H
XRAM is located at the upper end of the external data memory area.
MCD02768
Figure 1-3
XRAM Memory Mapping (256 Byte)
Depending on the C500 derivative, the size of the XRAM area differs from 128 upto
3K byte. Further, the XRAM can be enabled or disabled. If an internal XRAM area is
disabled, external data memory can be accessed in the address range of the internal
XRAM.
User’s Manual
1-5
2000-07
C500
Fundamental Structure
1.2.2.3
External Data Memory
The 64 Kbyte external data memory can be addressed by instructions that use 8-bit or
16-bit indirect addressing. A 16-bit external memory addressing mode is supported by
the MOVX instructions using the 16-bit datapointer DPTR for addressing. For 8-bit
addressing MOVX instructions with the general purpose registers R0/R1 are used.
1.2.3
Special Function Register Area
The registers of a C500 microcontroller, except the program counter and the four general
purpose register banks, reside in the special function register (SFR) area. The special
function register area typically provides 128 bytes of direct addressable SFRs. The
SFRs which are located at addresses with address bit 0-2 equal 0 (addresses 80 H, 88H,
90H, … F0H, F8H) are bitaddressable SFRs (see also Figure 1-1). For example, the SFR
with byte address 80H provides the bit locations with bit addresses 80H to 87H. The bit
addresses of the SFR bits reach from 80H to F8H.
Due to the limited number of 128 standard SFRs, some derivatives of the C500
microcontroller family provide an additional 128 byte SFR area, called the mapped SFR
area. The mapped SFR area provides the same addressing capabilities (direct
addresses, bit addressing) as the standard SFR area.
Special Function Register SYSCON (Address B1H)
Bit No. MSB
7
B1H
–
6
5
4
3
2
1
LSB
0
–
–
RMAP
–
–
–
–
SYSCON
The functions of the shaded bits are not described in this section.
Bit
Function
RMAP
Special function register map bit
RMAP = 0: The access to the non-mapped (standard) special
function register area is enabled (default after reset).
RMAP = 1: The access to the mapped special function register
area is enabled.
As long as bit RMAP is set, mapped special function registers can be accessed. This bit
is not cleared by hardware automatically. Thus, when non-mapped/mapped registers
are to be accessed, the bit RMAP must be cleared/set by software, respectively each.
Some registers (e.g. ACC) are accessed independently of bit RMAP.
User’s Manual
1-6
2000-07
C500
Fundamental Structure
Two bits in the program status word, RS0 (PSW.3) and RS1 (PSW.4), select the active
register bank. This allows fast context switching, which is useful when entering
subroutines or interrupt service routines. The 8 general purpose registers of the selected
register bank may be accessed by register addressing. For indirect addressing modes,
the registers R0 and R1 are used as pointer or index register to address internal or
external memory (e.g. MOV @R0).
User’s Manual
1-7
2000-07
C500
CPU Architecture
2
CPU Architecture
The typical architecture of a C500 family microcontroller is shown in Figure 2-1. This
block diagram includes all main functional blocks of the C500 microcontrollers. The
shaded blocks are basic functional units which are mandatory for each C500
microcontroller. The other functional blocks such as XRAM, peripheral units, and ROM/
RAM sizes are specific to each C500 microcontroller derivative.
Parallel
Port
IRAM
XRAM
Address Bus
Interrupt
Controller
Serial
Port
ROM
C500 Core
(1 or 8 Datapointer)
Parallel
Port
Peripheral
Bus
Timers
A
D
Access
Control
Control
MDU
Port0/Port2
Data Bus
Housekeeper
Ext.
Control
WDU
Basic functional blocks
Figure 2-1
RST
EA
PSEN
ALE
XTAL
MCB02769
C500 Microcontroller Architecture Block Diagram
The core block represents the CPU (Central Processing Unit) of the C500 family
microcontrollers. The CPU consists of the instruction decoder, the arithmetic section, the
CPU registers, and the program control section. The housekeeper unit generates
internal signals for controlling the functions of the individual internal units within the
microcontroller. Port 0 and port 2 are required for accessing external code and data
memory and for emulation purposes. The external control signals and the clock
generation are handled in the external control block. The access control unit is
responsible for the selection of the on-chip memory resources. The IRAM provides the
internal RAM which includes the general purpose registers. The interrupt requests from
the peripheral units are handled by an interrupt controller unit.
C500 device specific is the configuration of the on-chip peripheral units. Serial
interfaces, timers, capture/compare units, A/D converters, watchdog units, or a multiply/
divide unit are typical examples for on-chip peripheral units. The external signals of
these peripheral units are available at multifunctional parallel I/O ports or at dedicated
pins.
User’s Manual
2-1
2000-07
C500
CPU Architecture
The arithmetic section of the core performs extensive data manipulation and is
comprised of the arithmetic/logic unit (ALU), an A register, B register and PSW register.
Further, it has extensive facilities for binary and BCD arithmetic and excels in its bithandling capabilities. Efficient use of program memory results from an instruction set
consisting of 44% one-byte, 41% two-byte, and 15% three-byte instructions. The ALU
accepts 8-bit data words from one or two sources and generates an 8-bit result under
the control of the instruction decoder. The ALU performs the arithmetic operations add,
substract, multiply, divide, increment, decrement, BDC-decimal-add-adjust and
compare, and the logic operations AND, OR, Exclusive OR, complement and rotate
(right, left or swap nibble (left four)). Also included is a Boolean processor performing the
bit operations as set, clear, complement, jump-if-not-set, jump-if-set-and-clear and move
to/from carry. Between any addressable bit (or its complement) and the carry flag, it can
perform the bit operations of logical AND or logical OR with the result returned to the
carry flag.
The program control section of the core controls the sequence in which the instructions
stored in program memory are executed. The 16-bit program counter (PC) holds the
address of the next instruction to be executed. The conditional branch logic enables
internal and external events to the processor to cause a change in the program
execution sequence.
2.1
Accumulator
ACC is the symbol for the accumulator register. The mnemonics for accumulator-specific
instructions, however, refer to the accumulator simply as A.
2.2
B Register
The B register is used during multiply and divide and serves as both source and
destination. For other instructions it can be treated as another scratch pad register.
2.3
Program Status Word
The Program Status Word (PSW) contains several status bits that reflect the current
state of the CPU. The bits of the PSW are used for different functions which are: two
register bank selection bits, two carry flags and an overflow flag for arithmetic
instructions, a parity bit for the content of the ACC, and two general purpose flags.
The bit definitions of the PSW are shown on the next page.
User’s Manual
2-2
2000-07
C500
CPU Architecture
Special Function Register PSW (Address D0H)
Bit No.
D0H
Reset Value: 00H
MSB
LSB
7
6
5
4
3
2
1
0
CY
AC
F0
RS1
RS0
OV
F1
P
Bit
Function
CY
Carry Flag
Used by arithmetic and conditional branch instruction.
AC
Auxiliary Carry Flag
Used by instructions which execute BCD operations.
F0
General Purpose Flag
RS1
RS0
Register Bank select control bits
These bits are used to select one of the four register banks.
PSW
RS1 RS0 Function
0
0
Registerbank 0 at data address 00H - 07H selected
0
1
Registerbank 1 at data address 08H - 0FH selected
1
0
Registerbank 2 at data address 10H - 17H selected
1
1
Registerbank 3 at data address 18H - 1FH selected
OV
Overflow Flag
Used by arithmetic instruction.
F1
General Purpose Flag
P
Parity Flag
Always set/cleared by hardware to indicate an odd/even number of
“one” bits in the accumulator.
2.4
Stack Pointer
The stack pointer (SP) register is 8 bits wide. It is incremented before data is stored
during PUSH and CALL executions and decremented after data is popped during a POP
and RET (RETI) execution, i.e. it always points to the last valid stack byte. While the
stack may reside anywhere in the on-chip RAM, the stack pointer is initialized to 07H
after a reset. This causes the stack to begin a location = 08H above register bank zero.
The SP can be read or written under software control.
User’s Manual
2-3
2000-07
C500
CPU Architecture
2.5
Data Pointer
8-bit accesses to the internal XRAM data memory or the external data memory are
executed using the data pointer DPTR as an 16-bit address register. Normally, the C500
family microcontrollers have one data pointer. But some members of the C500 family
provide eight data pointers. The availability of eight data pointers especially supports the
programming in high level languages which have a demand to store data in large
external data memory portions.
Special Function Register DPL (Address 82 H)
Special Function Register DPH (Address 83H)
Special Function Register DPSEL (Address D0H)
Reset Value: 00H
Reset Value: 00H
Reset Value: 00H
MSB
LSB
Bit No.
7
6
5
4
3
2
1
0
82H
.7
.6
.5
.4
.3
.2
.1
LSB
DPL
83H
MSB
.6
.5
.4
.3
.2
.1
.0
DPH
92H
–
–
–
–
–
.2
.1
.0
DPSEL
Bit
Function
–
Reserved bits for future use
DPSEL.2 - 0 Data pointer select bits
DPSEL.2-0 defines the number of the actual active data
pointer.DPTR0-7.
User’s Manual
DPSEL2
DPSEL1 DPSEL0 Function
0
0
0
Data pointer 0 selected
0
0
1
Data pointer 1 selected
0
1
0
Data pointer 2 selected
0
1
1
Data pointer 3 selected
1
0
0
Data pointer 4 selected
1
0
1
Data pointer 5 selected
1
1
0
Data pointer 6 selected
1
1
1
Data pointer 7 selected
2-4
2000-07
C500
CPU Architecture
2.5.1
The Importance of Additional Datapointers
The standard 8051 architecture provides just one 16-bit pointer for indirect addressing
of external devices (memories, peripherals, latches, etc.). Except for a 16-bit “move
immediate” to this datapointer and an increment instruction, any other pointer handling
is to be done byte by byte. For complex applications with peripherals located in the
external data memory space (e.g. CAN controller) or extended data storage capacity this
turned out to be a “bottle neck” for the 8051’s communication to the external world.
Especially programming in high-level languages (PLM51, C51, PASCAL51) requires
extended RAM capacity and at the same time a fast access to this additional RAM
because of the reduced code efficiency of these languages.
2.5.2
How the eight Datapointers of the C500 are Realized
Simply adding more datapointers is not suitable because of the need to keep up 100%
compatibility to the 8051 instruction set. This instruction set, however, allows the
handling of only one single 16-bit datapointer (DPTR, consisting of the two 8-bit SFRs
DPH and DPL).
To meet both of the above requirements (speed up external accesses, 100%
compatibility to 8051 architecture) the C500 contains a set of eight 16-bit registers from
which the actual datapointer can be selected.
This means that the user’s program may keep up to eight 16-bit addresses resident in
these registers, but only one register at a time is selected to be the datapointer. Thus the
datapointer in turn is accessed (or selected) via indirect addressing. This indirect
addressing is done through a special function register called DPSEL (data pointer select
register). All instructions of the C500 which handle the datapointer therefore affect only
one of the eight pointers which is addressed by DPSEL at that very moment.
Figure 5-1 illustrates the addressing mechanism: a 3-bit field in register DPSEL points
to the currently used DPTRx. Any standard 8051 instruction (e.g. MOVX @DPTR, A transfer a byte from accumulator to an external location addressed by DPTR) now uses
this activated DPTRx.
User’s Manual
2-5
2000-07
C500
CPU Architecture
- - - - -
.2 .1 .0
DPSEL(92 H)
DPSEL
DPTR7
Selected
Data-
.2
.1
.0
pointer
0
0
0
DPTR 0
0
0
1
DPTR 1
0
1
0
DPTR 2
0
1
1
DPTR 3
1
0
0
DPTR 4
1
0
1
DPTR 5
1
1
0
DPTR 6
1
1
1
DPTR 7
Figure 2-2
2.5.3
DPTR0
DPH(83 H )
DPL(82 H)
External Data Memory
MCD00779
Accessing of External Data Memory via Multiple Datapointers
Advantages of Multiple Datapointers
Using the above addressing mechanism for external data memory results in less code
and faster execution of external accesses. Whenever the contents of the datapointer
must be altered between two or more 16-bit addresses, one single instruction, which
selects a new datapointer, does this job. If the program uses just one datapointer, then
it has to save the old value (with two 8-bit instructions) and load the new address, byte
by byte. This not only takes more time, it also requires additional space in the internal
RAM.
2.5.4
Application Example and Performance Analysis
The following example shall demonstrate the involvement of multiple data pointers in a
table transfer from the code memory to external data memory.
Start address of ROM source table:
Start address of table in external RAM:
User’s Manual
1FFFH
2FA0H
2-6
2000-07
C500
CPU Architecture
Example 1: Using only One Datapointer (Code for a C501)
Initialization Routine
MOV
MOV
MOV
MOV
LOW(SRC_PTR), #0FFH ;Initialize shadow_variables with source_pointer
HIGH(SRC_PTR), #1FH
LOW(DES_PTR), #0A0H ;Initialize shadow_variables with destination_pointer
HIGH(DES_PTR), #2FH
Table Look-up Routine under Real Time Conditions
PUSH
PUSH
MOV
MOV
;INC
;CJNE
MOVC
MOV
MOV
MOV
MOV
INC
DPL
DPH
DPL, LOW(SRC_PTR)
DPH, HIGH(SRC_PTR)
DPTR
…
A,@DPTR
LOW(SRC_PTR), DPL
HIGH(SRC_PTR), DPH
DPL, LOW(DES_PTR)
DPH, HIGH(DES_PTR)
DPTR
MOVX
MOV
MOV
POP
POP
@DPTR, A
LOW(DES_PTR), DPL
HIGH(DES_PTR),DPH
DPH
DPL
;
User’s Manual
;
Number of cycles
;Save old datapointer
2
;
2
;Load Source Pointer
2
;
2
Increment and check for end of table (execution time
not relevant for this consideration)
–
;Fetch source data byte from ROM table 2
;Save source_pointer and
2
;load destination_pointer
2
;
2
;
2
;Increment destination_pointer
;(ex. time not relevant)
–
;Transfer byte to destination address
2
;Save destination_pointer
2
;
2
;Restore old datapointer
2
;
2
Total execution time (machine cycles): 28
2-7
2000-07
C500
CPU Architecture
Example 2: Using Two Datapointers (Code for a C509)
Initialization Routine
MOV
MOV
MOV
MOV
DPSEL, #06H
DPTR, #1FFFH
DPSEL, #07H
DPTR, #2FA0H
;Initialize DPTR6 with source pointer
;Initialize DPTR7 with destination pointer
Table Look-up Routine under Real Time Conditions
PUSH
MOV
;INC
;CJNE
MOVC
MOV
DPSEL
DPSEL, #06H
DPTR
…
A,@DPTR
DPSEL, #07H
MOVX @DPTR, A
POP
DPSEL
;
;
Number of cycles
;Save old source pointer
2
;Load source pointer
2
Increment and check for end of table (execution time
not relevant for this consideration)
–
;Fetch source data byte from ROM table 2
;Save source_pointer and
;load destination_pointer
2
;Transfer byte to destination address
2
;Save destination pointer and
;restore old datapointer
2
Total execution time (machine cycles): 12
The above example shows that utilization of the C500’s multiple datapointers can make
external bus accesses two times as fast as with a standard 8051 or 8051 derivative.
Here, four data variables in the internal RAM and two additional stack bytes were
spared, too. This means for some applications where all eight datapointers are
employed that an C500 program has up to 24 byte (16 variables and 8 stack bytes) of
the internal RAM free for other use.
User’s Manual
2-8
2000-07
C500
CPU Architecture
2.6
Enhanced Hooks Emulation Concept
The Enhanced Hooks Emulation Concept of the C500 microcontroller family is a new,
innovative way to control the execution of C500 MCUs and to gain extensive information
on the internal operation of the controllers. Emulation of on-chip ROM based programs
is possible, too.
Each production chip has built-in logic for the support of the Enhanced Hooks Emulation
Concept. Therefore, no costly bond-out chips are necessary for emulation. This also
ensure that emulation and production chips are identical.
The Enhanced Hooks Technology™, which requires embedded logic in the C500, allows
the C500 together with an EH-IC to function similar to a bond-out chip. This simplifies
the design and reduces costs of an ICE-system. ICE-systems using an EH-IC and a
compatible C500 are able to emulate all operating modes of the different versions of the
C500. This includes emulation of ROM, ROM with code rollover and ROMless modes of
operation. It is also able to operate in single step mode and to read the SFRs after a
break.
ICE-System Interface
to Emulation Hardware
RESET
EA
ALE
PSEN
SYSCON
PCON
TCON
C500
MCU
RSYSCON
RPCON
RTCON
EH-IC
Enhanced Hooks
Interface Circuit
Port 0
Port 2
Optional
I/O Ports
Port 3
Port 1
RPort 2 RPort 0
Target System Interface
Figure 2-3
TEA TALE TPSEN
MCS02647
Basic C500 MCU Enhanced Hooks Concept Configuration
Port 0, port 2 and some of the control lines of the C500 based MCU are used by
Enhanced Hooks Emulation Concept to control the operation of the device during
emulation and to transfer informations about the program execution and data transfer
between the external emulation hardware (ICE-system) and the C500 MCU.
User’s Manual
2-9
2000-07
C500
CPU Architecture
2.7
Basic Interrupt Handling
Each member of the C500 microcontroller family provides several interrupt sources.
These interrupts are generated typically by external events or by the internal peripheral
units. If an interrupt is accepted by the CPU, the microcontroller interrupts a running
program and proceeds the program execution at an interrupt source specific vector
address where the interrupt service routine is located. After the execution of a RETI
(return from interrupt) instruction the program is continued at the point where it has been
interrupted. Figure 2-4 shows an example for the interrupt vector addresses of a C500
microcontroller (C501). Generally, interrupt vector addresses are located in the code
memory area starting at address 0003H. The minimum distance between two
consecutive vector addresses is always 8 bytes. Therefore, interrupt vectors can be
assigned to the following addresses: 0003H, 000BH, 0013H, 001BH, 0023H, 002BH,
0033H … 00FBH.
FFFF H
~
~
002B H
0023 H
001B H
0013 H
000B H
0003 H
0000 H
Program
Memory
~
~
Timer 2
Interrupt
Serial Port
Interrupt
Timer 1
Interrupt
External
Interrupt 1
Timer 0
Interrupt
8 Bytes
External
Interrupt 0
Reset
MCD02770
Figure 2-4
Interrupt Vector Addresses (Example of the C501)
An interrupt source indicates to the interrupt controller an interrupt condition by setting
an interrupt request flag. The interrupt request flags are sampled in each machine cycle.
The sampled flags are polled during the following machine cycle. If one of the flags was
in a set condition in the preceeding cycle, the polling cycle will find it and the interrupt
controller will cause the CPU to branch to the vector address of the appropriate service
routine by generating an internal LCALL. This hardware-generated LCALL is blocked by
any of the following conditions:
User’s Manual
2-10
2000-07
C500
CPU Architecture
1. An interrupt of equal or higher priority is already in progress.
2. The current (polling) cycle is not in the final cycle of the instruction in progress.
3. The instruction in progress is RETI or any write access to interrupt enable or priority
registers.
Any of these three conditions will block the generation of the LCALL to the interrupt
service routine. Condition 2 ensures that the instruction in progress is completed before
vectoring to any service routine. Condition 3 ensures that if the instruction in progress is
RETI or any write access to interrupt enable or interrupt priority registers, then at least
one more instruction will be executed before any interrupt is vectored too; this delay
guarantees that changes of the interrupt status can be observed by the interrupt
controller.
The polling cycle is repeated with each machine cycle, and the values polled are the
values that were present at the previous machine cycle. Note that if any interrupt flag is
active but not being responded to for one of the conditions already mentioned, or if the
flag is no longer active when the blocking condition is removed, the denied interrupt will
not be serviced. In other words, the fact that the interrupt flag was once active but not
serviced is not remembered. Every polling cycle interrogates only the pending interrupt
requests.
The polling cycle/LCALL sequence is illustrated in Figure 2-5.
C1
C2
C3
C4
C5
S5P2
Interrupt
is latched
Figure 2-5
Interrupts
are polled
Long Call to Interrupt
Vector Address
Interrupt
Routine
MCT01859
Interrupt Detection/Entry Diagram
Note that if an interrupt of a higher priority level goes active prior to S5P2 in the machine
cycle labeled C3 in Figure 2-5 then, in accordance with the above rules, it will be
vectored to during C5 and C6 without any instruction for the lower priority routine to be
executed.
Thus, the processor acknowledges an interrupt request by executing a hardwaregenerated LCALL to the appropriate servicing routine. In some cases it also clears the
flag that generated the interrupt, while in other cases it does not; then this has to be done
by the user’s software.
User’s Manual
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2000-07
C500
CPU Architecture
The program execution proceeds from that location until the RETI instruction is
encountered. The RETI instruction informs the processor that the interrupt routine is no
longer in progress, then pops the two top bytes from the stack and reloads the program
counter. Execution of the interrupted program continues from the point where it was
stopped. Note that the RETI instruction is very important because it informs the
processor that the program left the current interrupt priority level. A simple RET
instruction would also have returned execution to the interrupted program, but it would
have left the interrupt control system thinking an interrupt was still in progress. In this
case no interrupt of the same or lower priority level would be acknowledged.
2.8
Interrupt Response Time
If an external interrupt is recognized, its corresponding request flag is set at S5P2 in
every machine cycle. The value is not polled by the circuitry until the next machine cycle.
If the request is active and conditions are right for it to be acknowledged, a hardware
subroutine call to the requested service routine will be next instruction to be executed.
The call itself takes two cycles. Thus a minimum of three complete machine cycles will
elapse between activation and external interrupt request and the beginning of execution
of the first instruction of the service routine.
A longer response time would be obtained if the request was blocked by one of the three
previously listed conditions. If an interrupt of equal or higher priority is already in
progress, the additional wait time obviously depends on the nature of the other
interrupt’s service routine. If the instruction in progress is not in its final cycle, the
additional wait time cannot be more than 3 cycles since the longest instructions (MUL
and DIV) are only 4 cycles long; and, if the instruction in progress is RETI or a write
access to interrupt enable or interrupt priority registers the additional wait time cannot be
more than 5 cycles (a maximum of one more cycle to complete the instruction in
progress, plus 4 cycles to complete the next instruction, if the instruction is MUL or DIV).
Thus a single interrupt system, the response time is always more than 3 cycles and less
than 9 cycles.
User’s Manual
2-12
2000-07
C500
CPU Timing
3
CPU Timing
3.1
Basic Timing
A machine cycle consists of 6 states. Each state is divided into a phase 1 half, during
which the phase 1 clock is active, and a phase 2 half, during which the phase 2 clock is
active. Thus, a machine cycle consists of the states S1P1 (state 1, phase 1) through
S6P2 (state 6, phase 2). Depending on the C500 type of microcontroller, each state lasts
either one or two periods of the oscillator clock. Typically, arithmetic and logical
operations take place during phase 1 and internal register-to-register transfers take
place during phase 2.
The diagrams in Figure 3-1 show the fetch/execute timing related to the internal states
and phases. Since these internal clock signals are not user-accessible, the ALE
(address latch enable) signal is shown for external reference. ALE is normally activated
twice during each machine cycle: once during S1P2 and S2P1, and again during S4P2
and S5P1.
The execution of a one-cycle instruction begins at S1P2, when the opcode is latched into
the instruction register. If it is a two-byte instruction, the second reading takes place
during S4 of the same machine cycle. If it is a one-byte instruction, there is still a fetch
at S4, but the byte read (which would be the next op-code) is ignored (discarded fetch),
and the program counter is not incremented. In any case, execution is completed at the
end of S6P2.
Figure 3-1 (a) and (b) show the timing of a 1-byte, 1-cycle instruction and for a 2-byte,
1-cycle instruction.
Most C500 instructions are executed in one cycle. MUL (multiply) and DIV (divide) are
the only instructions that take more than two cycles to complete; they take four cycles.
Normally two code bytes are fetched from the program memory during every machine
cycle. The only exception to this is when a MOVX instruction is executed. MOVX is a
one-byte, 2-cycle instruction that accesses external data memory. During a MOVX, the
two fetches in the second cycle are skipped while the external data memory is being
addressed and strobed. Figure 3-1 (c) and (d) show the timing for a normal 1-byte,
2-cycle instruction and for a MOVX instruction.
User’s Manual
3-1
2000-07
C500
CPU Timing
S1 S2
S3
S4
S5
S6
S1 S2
S3
S4
S5
S6
P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2
ALE
Read
Opcode
S1
S2
Read next
Opcode (Discard)
S3
S4
S5
Read next
Opcode again
S6
a) 1 Byte, 1-Cycle Instruction, e.g. INC A
Read 2nd
Byte
Read
Opcode
S1
S2
S3
S4
S5
Read next
Opcode
S6
b) 2 Byte, 1-Cycle Instruction, e.g. ADD A, #Data
Read next Opcode again
Read
Opcode
S1
S2
Read next Opcode (Discard)
S3
S4
S5
S6
S1
S2
S3
S4
S5
S6
c) 1 Byte, 2-Cycle Instruction, e.g. INC DPTR
S1
S2
d) MOVX (1 Byte, 2-Cycle)
Read next Opcode again
Read next
Opcode
(Discard)
Read
Opcode
(MOVX)
S3
S4
S5
S6
ADDR
No Fetch
No ALE
S1
S2
S3
User’s Manual
S4
S5
S6
DATA
Access of External Memory
Figure 3-1
No Fetch
MCD02771
Fetch Execute Sequence
3-2
2000-07
C500
CPU Timing
3.2
Accessing External Memory
There are two types of external memory accesses: accesses to external program
memory and accesses to external data memory. Accesses to external program memory
use the signal PSEN (program store enable) as the read strobe. Accesses to external
data memory use the RD or WR (alternate functions of P3.7 and P3.6) to access the
memory.
Fetches from external program memory always use a 16-bit address. Accesses to
external data memory can use either a 16-bit address (MOVX @DPTR) or an 8-bit
address (MOVX @Ri). Whenever a 16-bit address is used, the high byte of the address
comes out on port 2, where it is held for the duration of the read, write, or code fetch
cycle.
If an 8-bit address is being used (MOVX @Ri), the contents of the port 2 SFR remain at
the port 2 pins throughout the whole external memory cycle. In this case, port 2 pins can
be used to page the external data memory.
In either case, the low byte of the address is time-multiplexed with the data byte on
port 0. The ADDRESS/DATA signal drives both FETS in the port 0 output buffers. Thus,
in external bus mode the port 0 pins are not open-drain outputs and do not require
external pullups. The ALE (address latch enable) signal should be used to latch the
address byte into an external latch. The address byte is valid at the negative transition
of ALE. Then, in a write cycle, the data byte to be written appears on port 0 just before
WR is activated, and remains there until WR is deactivated. In a read cycle, the incoming
byte is accepted at port 0 just before the read strobe (RD) is deactivated.
During any access to external memory, the CPU writes FFH to the port 0 latch (the
special function register), thus obliterating the information in the port 0 SFR. Also, a MOV
P0 instruction must not take place during external memory accesses. If the user writes
to port 0 during an external memory fetch, the incoming code byte may be corrupted.
Therefore, do not write to port 0 if external memory is used.
3.2.1
Accessing External Program Memory
External program memory is accessed under two conditions:
1. Whenever signal EA is active (low), or
2. Whenever signal EA is inactive (high) and the program counter (PC) contains an
address greater than the internal ROM size (e.g. 1FFFFH for an 8K internal ROM or
3FFFH for an 16K internal ROM).
This requires that the ROMless versions have always EA wired to Vss to enable the lower
8K, 16K, or 32K program bytes to be fetched from external memory.
When the CPU is executing out from external program memory (see timing diagram in
Figure 3-2), all 8 bits of port 2 are dedicated to an output function and may not be used
for general purpose I/O. During external program fetches they output the high byte of the
PC with the port 2 drivers using the strong pullups to emit bits that are 1’s.
User’s Manual
3-3
2000-07
C500
CPU Timing
States
S1
S2
S3
S4
S5
S6
S1
S2
P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2
ALE
PSEN
P0
P2
Data
Sampled
Data
Sampled
Data
Sampled
PCL
Out
PCL
Out
PCL
Out
PCH Out
PCH Out
PCH Out
MCD02772
Figure 3-2
3.2.2
External Program Memory Fetches
Accessing External Data Memory
The port 2 drivers use the strong pullups during the entire time that they are emitting
address bits that are 1’s. This occurs when the MOVX @DPTR instruction is executed
and when external program fetches are executed. During this time the port 2 latch (the
special function register) does not have to contain 1’s, and the contents of the port 2 SFR
are not modified. If the external memory cycle is not immediately followed by another
external memory cycle, the undisturbed contents of the port 2 SFR will reappear in the
next cycle.
Figure 3-3 and Figure 3-4 show in detail the timings of the external data memory read
and write cycles.
User’s Manual
3-4
2000-07
C500
CPU Timing
States
S4
S5
S6
S1
S2
S3
S4
S5
P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2
ALE
RD
PCL out if
program memory
is external
Data
Sampled
DPL or Ri
Out
P0
P2
PCH or
P2 SFR
Float
Float
PCH or
P2 SFR
DPH or P2 SFR Out
MCD02773
Figure 3-3
External Data Memory Read Cycle
States
S6
S1
S2
S3
S4
S5
S4
S5
P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2 P1 P2
ALE
WR
PCL out if
program memory
is external
DPL or Ri
Out
P0
Data Out
PCL Out
P2
PCH or
P2 SFR
DPH or P2 SFR Out
PCH or
P2 SFR
MCD02774
Figure 3-4
User’s Manual
External Data Memory Write Cycle
3-5
2000-07
C500
Instruction Set
4
Instruction Set
The C500 8-bit microcontroller family instruction set includes 111 instructions, 49 of
which are single-byte, 45 two-byte and 17 three-byte instructions. The instruction
opcode format consists of a function mnemonic followed by a “destination, source”
operand field. This field specifies the data type and addressing method(s) to be used.
Like all other members of the 8051-family, the C500 microcontrollers can be
programmed with the same instruction set common to the basic member, the SAB 8051.
Thus, the C500 family microcontrollers are 100% software compatible to the SAB 8051
and may be programmed with 8051 assembler or high-level languages.
4.1
Addressing Modes
The C500 uses five addressing modes:
–
–
–
–
–
register
direct
immediate
register indirect
base register plus index-register indirect
Table 4-1 summarizes the memory spaces which may be accessed by each of the
addressing modes.
Register Addressing
Register addressing accesses the eight working registers (R0 - R7) of the selected
register bank. The least significant bit of the instruction opcode indicates which register
is to be used. ACC, B, DPTR and CY, the Boolean processor accumulator, can also be
addressed as registers.
Direct Addressing
Direct addressing is the only method of accessing the special function registers. The
lower 128 bytes of internal RAM are also directly addressable.
Immediate Addressing
Immediate addressing allows constants to be part of the instruction in program memory.
User’s Manual
4-1
2000-07
C500
Instruction Set
Table 4-1
Addressing Modes and Associated Memory Spaces
Addressing Modes
Associated Memory Spaces
Register addressing
R0 through R7 of selected register bank, ACC, B, CY (Bit),
DPTR
Direct addressing
Lower 128 bytes of internal RAM, special function registers
Immediate addressing
Program memory
Register indirect
addressing
Internal RAM (@R1, @R0, SP), external data memory
(@R1, @R0, @DPTR)
Base register plus index
register addressing
Program memory (@A + DPTR, @A + PC)
Register Indirect Addressing
Register indirect addressing uses the contents of either R0 or R1 (in the selected register
bank) as a pointer to locations in a 256-byte block: the 256 bytes of internal RAM or the
lower 256 bytes of external data memory. Note that the special function registers are not
accessible by this method. The upper half of the internal RAM can be accessed by
indirect addressing only. Access to the full 64 Kbytes of external data memory address
space is accomplished by using the 16-bit data pointer. Execution of PUSH and POP
instructions also uses register indirect addressing. The stack may reside anywhere in the
internal RAM.
Base Register plus Index Register Addressing
Base register plus index register addressing allows a byte to be accessed from program
memory via an indirect move from the location whose address is the sum of a base
register (DPTR or PC) and index register, ACC. This mode facilitates look-up table
accesses.
Boolean Processor
The Boolean processor is a bit processor integrated into the C500 family
microcontrollers. It has its own instruction set, accumulator (the carry flag), bitaddressable RAM and l/O.
The bit manipulation instructions allow:
–
–
–
–
–
–
–
set bit
clear bit
complement bit
jump if bit is set
jump if bit is not set
jump if bit is set and clear bit
move bit from / to carry
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4-2
2000-07
C500
Instruction Set
Addressable bits, or their complements, may be logically AND-ed or OR-ed with the
contents of the carry flag. The result is returned to the carry register.
4.2
Introduction to the Instruction Set
The instruction set is divided into four functional groups:
–
–
–
–
data transfer
arithmetic
logic
control transfer
4.2.1
Data Transfer Instructions
Data transfer operations are divided into three classes:
– general-purpose
– accumulator-specific
– address-object
None of these operations affects the PSW flag settings except a POP or MOV directly to
the PSW.
General-Purpose Transfers
– MOV performs a bit or byte transfer from the source operand to the destination
operand.
– PUSH increments the SP register and then transfers a byte from the source operand
to the stack location currently addressed by SP.
– POP transfers a byte operand from the stack location addressed by the SP to the
destination operand and then decrements SP.
Accumulator-Specific Transfers
– XCH exchanges the byte source operand with register A (accumulator).
– XCHD exchanges the low-order nibble of the source operand byte with the low-order
nibble of A.
– MOVX performs a byte move between the external data memory and the
accumulator. The external address can be specified by the DPTR register (16 bit) or
the R1 or R0 register (8 bit).
– MOVC moves a byte from program memory to the accumulator. The operand in A is
used as an index into a 256-byte table pointed to by the base register (DPTR or PC).
The byte operand accessed is transferred to the accumulator.
User’s Manual
4-3
2000-07
C500
Instruction Set
Address-Object Transfer
– MOV DPTR, #data loads 16 bits of immediate data into a pair of destination registers,
DPH and DPL.
4.2.2
Arithmetic Instructions
The C500 family microcontrollers have four basic mathematical operations. Only 8-bit
operations using unsigned arithmetic are supported directly. The overflow flag, however,
permits the addition and subtraction operation to serve for both unsigned and signed
binary integers. Arithmetic can also be performed directly on packed BCD
representations.
Addition
– INC (increment) adds one to the source operand and puts the result in the operand
(flags in PSW are not affected).
– ADD adds A to the source operand and returns the result to A.
– ADDC (add with carry) adds A and the source operand, then adds one (1) if CY is set,
and puts the result in A.
– DA (decimal-add-adjust for BCD addition) corrects the sum which results from the
binary addition of two-digit decimal operands. The packed decimal sum formed by DA
is returned to A. CY is set if the BCD result is greater than 99; otherwise, it is cleared.
Subtraction
– SUBB (subtract with borrow) subtracts the second source operand from the first
operand (the accumulator), subtracts one (1) if CY is set and returns the result to A.
– DEC (decrement) subtracts one (1) from the source operand and returns the result to
the operand (flags in PSW are not affected).
Multiplication
– MUL performs an unsigned multiplication of the A register by the B register, returning
a double byte result. A receives the low-order byte, B receives the high-order byte. OV
is cleared if the top half of the result is zero and is set if it is not zero. CY is cleared.
AC is unaffected.
Division
– DIV performs an unsigned division of the A register by the B register; it returns the
integer quotient to the A register and returns the fractional remainder to the B register.
Division by zero leaves indeterminate data in registers A and B and sets OV;
otherwise, OV is cleared. CY is cleared. AC remains unaffected.
User’s Manual
4-4
2000-07
C500
Instruction Set
Flags
Unless otherwise stated in the previous descriptions, the flags of PSW are affected as
follows:
– CY is set if the operation causes a carry to or a borrow from the resulting high-order
bit; otherwise CY is cleared.
– AC is set if the operation results in a carry from the low-order four bits of the result
(during addition), or a borrow from the high-order bits to the low-order bits (during
subtraction); otherwise AC is cleared.
– OV is set if the operation results in a carry to the high-order bit of the result but not a
carry from the bit, or vice versa; otherwise OV is cleared. OV is used in two’scomplement arithmetic, because it is set when the signal result cannot be represented
in 8 bits.
– P is set if the modulo-2 sum of the eight bits in the accumulator is 1 (odd parity);
otherwise P is cleared (even parity). When a value is written to the PSW register, the
P bit remains unchanged, as it always reflects the parity of A.
4.2.3
Logic Instructions
The C500 family microcontrollers perform basic logic operations on both bit and byte
operands.
Single-Operand Operations
– CLR sets A or any directly addressable bit to zero (0).
– SETB sets any directly bit-addressable bit to one (1).
– CPL is used to complement the contents of the A register without affecting any flag,
or any directly addressable bit location.
– RL, RLC, RR, RRC, SWAP are the five operations that can be performed on A. RL,
rotate left, RR, rotate right, RLC, rotate left through carry, RRC, rotate right through
carry, and SWAP, rotate left four. For RLC and RRC the CY flag becomes equal to
the last bit rotated out. SWAP rotates A left four places to exchange bits 3 through 0
with bits 7 through 4.
Two-Operand Operations
– ANL performs bitwise logical AND of two operands (for both bit and byte operands)
and returns the result to the location of the first operand.
– ORL performs bitwise logical OR of two source operands (for both bit and byte
operands) and returns the result to the location of the first operand.
– XRL performs logical Exclusive OR of two source operands (byte operands) and
returns the result to the location of the first operand.
User’s Manual
4-5
2000-07
C500
Instruction Set
4.2.4
Control Transfer Instructions
There are three classes of control transfer operations: unconditional calls, returns,
jumps, conditional jumps, and interrupts. All control transfer operations, some upon a
specific condition, cause the program execution to continue a non-sequential location in
program memory.
Unconditional Calls, Returns and Jumps
Unconditional calls, returns and jumps transfer control from the current value of the
program counter to the target address. Both direct and indirect transfers are supported.
– ACALL and LCALL push the address of the next instruction onto the stack and then
transfer control to the target address. ACALL is a 2-byte instruction used when the
target address is in the current 2K page. LCALL is a 3-byte instruction that addresses
the full 64K program space. In ACALL, immediate data (i.e. an 11-bit address field) is
concatenated to the five most significant bits of the PC (which is pointing to the next
instruction). If ACALL is in the last 2 bytes of a 2K page then the call will be made to
the next page since the PC will have been incremented to the next instruction prior to
execution.
– RET transfers control to the return address saved on the stack by a previous call
operation and decrements the SP register by two (2) to adjust the SP for the popped
address.
– AJMP, LJMP and SJMP transfer control to the target operand. The operation of AJMP
and LJMP are analogous to ACALL and LCALL. The SJMP (short jump) instruction
provides for transfers within a 256-byte range centered about the starting address of
the next instruction (– 128 to + 127).
– JMP @A + DPTR performs a jump relative to the DPTR register. The operand in A is
used as the offset (0 - 255) to the address in the DPTR register. Thus, the effective
destination for a jump can be anywhere in the program memory space.
User’s Manual
4-6
2000-07
C500
Instruction Set
Conditional Jumps
Conditional jumps perform a jump contingent upon a specific condition. The destination
will be within a 256-byte range centered about the starting address of the next instruction
(– 128 to + 127).
–
–
–
–
–
–
–
JZ performs a jump if the accumulator is zero.
JNZ performs a jump if the accumulator is not zero.
JC performs a jump if the carry flag is set.
JNC performs a jump if the carry flag is not set.
JB performs a jump if the directly addressed bit is set.
JNB performs a jump if the directly addressed bit is not set.
JBC performs a jump if the directly addressed bit is set and then clears the directly
addressed bit.
– CJNE compares the first operand to the second operand and performs a jump if they
are not equal. CY is set if the first operand is less than the second operand; otherwise
it is cleared. Comparisons can be made between A and directly addressable bytes in
internal data memory or an immediate value and either A, a register in the selected
register bank, or a register indirectly addressable byte of the internal RAM.
– DJNZ decrements the source operand and returns the result to the operand. A jump
is performed if the result is not zero. The source operand of the DJNZ instruction may
be any directly addressable byte in the internal data memory. Either direct or register
addressing may be used to address the source operand.
Interrupt Returns
– RETI transfers control as RET does, but additionally enables interrupts of the current
priority level.
User’s Manual
4-7
2000-07
C500
Instruction Set
4.3
Instruction Definitions
All 111 instructions of the C500 family microcontrollers can essentially be condensed to
53 basic operations, in the following alphabetically ordered according to the operation
mnemonic section.
Table 4-2
PSW Flag Modification (CY,OV,AC)
Instruction
Flag
Instruction
Flag
CY
OV
AC
CY
ADD
X
X
X
SETB C
1
ADDC
X
X
X
CLR C
0
SUBB
X
X
X
CPL C
X
MUL
0
X
ANL C,bit
X
DIV
0
X
ANL C,/bit
X
DA
X
ORL C,bit
X
RRC
X
ORL C,/bit
X
RLC
X
MOV C,bit
X
CJNE
X
OV
AC
A brief example of how the instruction might be used is given as well as its effect on the
PSW flags. The number of bytes and machine cycles required, the binary machine
language encoding, and a symbolic description or restatement of the function is also
provided.
Note:
Only the carry, auxiliary carry, and overflow flags are discussed. The parity bit is always
computed from the actual content of the accumulator.
Similarly, instructions which alter directly addressed registers could affect the other
status flags if the instruction is applied to the PSW. Status flags can also be modified by
bit manipulation.
User’s Manual
4-8
2000-07
C500
Instruction Set
Notes on Data Addressing Modes
Rn
-
Working register R0-R7
direct
-
128 internal RAM locations, any l/O port, control or status register
@Ri
-
Indirect internal or external RAM location addressed by register R0 or R1
#data
-
8-bit constant included in instruction
#data 16 -
16-bit constant included as bytes 2 and 3 of instruction
bit
-
128 software flags, any bit-addressable l/O pin, control or status bit
A
-
Accumulator
Notes on Program Addressing Modes:
addr16
-
Destination address for LCALL and LJMP may be anywhere within the
64-Kbyte program memory address space.
addr11
-
Destination address for ACALL and AJMP will be within the same 2-Kbyte
page of program memory as the first byte of the following instruction.
rel
-
SJMP and all conditional jumps include an 8-bit offset byte. Range is
+ 127/– 128 bytes relative to the first byte of the following instruction.
All mnemonics copyrighted:  Intel Corporation 1980
User’s Manual
4-9
2000-07
C500
Instruction Set
ACALL
addr11
Function:
Absolute call
Description:
ACALL unconditionally calls a subroutine located at the indicated
address. The instruction increments the PC twice to obtain the address of
the following instruction, then pushes the 16-bit result onto the stack (loworder byte first) and increments the stack pointer twice. The destination
address is obtained by successively concatenating the five high-order bits
of the incremented PC, op code bits 7-5, and the second byte of the
instruction. The subroutine called must therefore start within the same
2K block of program memory as the first byte of the instruction following
ACALL. No flags are affected.
Example:
Initially SP equals 07H. The label “SUBRTN” is at program memory
location 0345H. After executing the instruction
ACALL
SUBRTN
at location 0123H, SP will contain 09H, internal RAM location 08H and 09H
will contain 25H and 01H, respectively, and the PC will contain 0345H.
Operation:
ACALL
(PC) ← (PC) + 2
(SP) ← (SP) + 1
((SP)) ← (PC7-0)
(SP) ← (SP) + 1
((SP)) ← (PC15-8)
(PC10-0) ← page address
Encoding:
a10 a9 a8 1 0 0 0 1
Bytes:
2
Cycles:
2
User’s Manual
a7 a6 a5 a4 a3 a2 a1 a0
4-10
2000-07
C500
Instruction Set
ADD
A, <src-byte>
Function:
Add
Description:
ADD adds the byte variable indicated to the accumulator, leaving the
result in the accumulator. The carry and auxiliary carry flags are set,
respectively, if there is a carry out of bit 7 or bit 3, and cleared otherwise.
When adding unsigned integers, the carry flag indicates an overflow
occurred.
OV is set if there is a carry out of bit 6 but not out of bit 7, or a carry out of
bit 7 but not out of bit 6; otherwise OV is cleared. When adding signed
integers, OV indicates a negative number produced as the sum of two
positive operands, or a positive sum from two negative operands.
Four source operand addressing modes are allowed: register, direct,
register-indirect, or immediate.
Example:
The accumulator holds 0C3H (11000011B) and register 0 holds 0AAH
(10101010B).
The instruction
ADD
A,R0
will leave 6DH (01101101B) in the accumulator with the AC flag cleared
and both the carry flag and OV set to 1.
ADD
A,Rn
Operation:
ADD
(A) ← (A) + (Rn)
Encoding:
0 0 1 0 1 r r r
Bytes:
1
Cycles:
1
ADD
A,direct
Operation:
ADD
(A) ← (A) + (direct)
Encoding:
0 0 1 0 0 1 0 1
Bytes:
2
Cycles:
1
User’s Manual
direct address
4-11
2000-07
C500
Instruction Set
ADD
A, @Ri
Operation:
ADD
(A) ← (A) + ((Ri))
Encoding:
0 0 1 0 0 1 1 i
Bytes:
1
Cycles:
1
ADD
A, #data
Operation:
ADD
(A) ← (A) + #data
Encoding:
0 0 1 0 0 1 0 0
Bytes:
2
Cycles:
1
User’s Manual
immediate data
4-12
2000-07
C500
Instruction Set
ADDC
A, < src-byte>
Function:
Add with carry
Description:
ADDC simultaneously adds the byte variable indicated, the carry flag and
the accumulator contents, leaving the result in the accumulator. The carry
and auxiliary carry flags are set, respectively, if there is a carry out of bit
7 or bit 3, and cleared otherwise. When adding unsigned integers, the
carry flag indicates an overflow occurred.
OV is set if there is a carry out of bit 6 but not out of bit 7, or a carry out of
bit 7 but not out of bit 6; otherwise OV is cleared. When adding signed
integers, OV indicates a negative number produced as the sum of two
positive operands or a positive sum from two negative operands.
Four source operand addressing modes are allowed: register, direct,
register-indirect, or immediate.
Example:
The accumulator holds 0C3H (11000011B) and register 0 holds 0AAH
(10101010B) with the carry flag set. The instruction
ADDC
A,R0
will leave 6EH (01101110B) in the accumulator with AC cleared and both
the carry flag and OV set to 1.
ADDC
A,Rn
Operation:
ADDC
(A) ← (A) + (C) + (Rn)
Encoding:
0 0 1 1 1 r r r
Bytes:
1
Cycles:
1
ADDC
A,direct
Operation:
ADDC
(A) ← (A) + (C) + (direct)
Encoding:
0 0 1 1 0 1 0 1
Bytes:
2
Cycles:
1
User’s Manual
direct address
4-13
2000-07
C500
Instruction Set
ADDC
A, @Ri
Operation:
ADDC
(A) ← (A) + (C) + ((Ri))
Encoding:
0 0 1 1 0 1 1 i
Bytes:
1
Cycles:
1
ADDC
A, #data
Operation:
ADDC
(A) ← (A) + (C) + #data
Encoding:
0 0 1 1 0 1 0 0
Bytes:
2
Cycles:
1
User’s Manual
immediate data
4-14
2000-07
C500
Instruction Set
AJMP
addr11
Function:
Absolute jump
Description:
AJMP transfers program execution to the indicated address, which is
formed at run-time by concatenating the high-order five bits of the PC
(after incrementing the PC twice), op code bits 7-5, and the second byte
of the instruction. The destination must therefore be within the same 2K
block of program memory as the first byte of the instruction following
AJMP.
Example:
The label “JMPADR” is at program memory location 0123H. The
instruction
AJMP
JMPADR
is at location 0345H and will load the PC with 0123H.
Operation:
AJM P
(PC) ← (PC) + 2
(PC10-0) ← page address
Encoding:
a10 a9 a8 0 0 0 0 1
Bytes:
2
Cycles:
2
User’s Manual
a7 a6 a5 a4 a3 a2 a1 a0
4-15
2000-07
C500
Instruction Set
ANL
<dest-byte>, <src-byte>
Function:
Logical AND for byte variables
Description:
ANL performs the bitwise logical AND operation between the variables
indicated and stores the results in the destination variable. No flags are
affected (except P, if <dest-byte> = A).
The two operands allow six addressing mode combinations. When the
destination is a accumulator, the source can use register, direct, registerindirect, or immediate addressing; when the destination is a direct
address, the source can be the accumulator or immediate data.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
If the accumulator holds 0C3H (11000011B) and register 0 holds 0AAH
(10101010B) then the instruction
ANL
A,R0
will leave 81H (10000001B) in the accumulator.
When the destination is a directly addressed byte, this instruction will clear
combinations of bits in any RAM location or hardware register. The mask
byte determining the pattern of bits to be cleared would either be a
constant contained in the instruction or a value computed in the
accumulator at run-time.
The instruction
ANL
P1, #01110011B
will clear bits 7, 3, and 2 of output port 1.
ANL
A,Rn
Operation:
ANL
(A) ← (A) ∧ (Rn)
Encoding:
0 1 0 1 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-16
2000-07
C500
Instruction Set
ANL
A,direct
Operation:
ANL
(A) ← (A) ∧ (direct)
Encoding:
0 1 0 1 0 1 0 1
Bytes:
2
Cycles:
1
ANL
A, @Ri
Operation:
ANL
(A) ← (A) ∧ ((Ri))
Encoding:
0 1 0 1 0 1 1 i
Bytes:
1
Cycles:
1
ANL
A, #data
Operation:
ANL
(A) ← (A) ∧ #data
Encoding:
0 1 0 1 0 1 0 0
Bytes:
2
Cycles:
1
ANL
direct,A
Operation:
ANL
(direct) ← (direct) ∧ (A)
Encoding:
0 1 0 1 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
direct address
immediate data
direct address
4-17
2000-07
C500
Instruction Set
ANL
direct, #data
Operation:
ANL
(direct) ← (direct) ∧ #data
Encoding:
0 1 0 1 0 0 1 1
Bytes:
3
Cycles:
2
User’s Manual
direct address
4-18
immediate data
2000-07
C500
Instruction Set
ANL
C, <src-bit>
Function:
Logical AND for bit variables
Description:
If the Boolean value of the source bit is a logic 0 then clear the carry flag;
otherwise leave the carry flag in its current state. A slash (“/” preceding the
operand in the assembly language indicates that the logical complement
of the addressed bit is used as the source value, but the source bit itself
is not affected. No other flags are affected.
Only direct bit addressing is allowed for the source operand.
Example:
Set the carry flag if, and only if, P1.0 = 1, ACC.7 = 1, and OV = 0:
MOV
ANL
ANL
C,P1.0 ; Load carry with input pin state
C,ACC.7 ; AND carry with accumulator bit 7
C,/OV
; AND with inverse of overflow flag
ANL
C,bit
Operation:
ANL
(C) ← (C) ∧ (bit)
Encoding:
1 0 0 0 0 0 1 0
Bytes:
2
Cycles:
2
ANL
C,/bit
Operation:
ANL
(C) ← (C) ∧ / (bit)
Encoding:
1 0 1 1 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
bit address
bit address
4-19
2000-07
C500
Instruction Set
CJNE
<dest-byte >, < src-byte >, rel
Function:
Compare and jump if not equal
Description:
CJNE compares the magnitudes of the tirst two operands, and branches
if their values are not equal. The branch destination is computed by
adding the signed relative displacement in the last instruction byte to the
PC, after incrementing the PC to the start of the next instruction. The carry
flag is set if the unsigned integer value of <dest-byte> is less than the
unsigned integer value of <src-byte>; otherwise, the carry is cleared.
Neither operand is affected.
The first two operands allow four addressing mode combinations: the
accumulator may be compared with any directly addressed byte or
immediate data, and any indirect RAM location or working register can be
compared with an immediate constant.
Example:
The accumulator contains 34H. Register 7 contains 56H. The first
instruction in the sequence
;
NOT_EQ
;
CJNE
. . .
JC
. . .
R7, # 60H, NOT_EQ
. . . . .
REQ_LOW
. . . . .
; R7 = 60H
; If R7 < 60H
; R7 > 60H
sets the carry flag and branches to the instruction at label NOT_EQ. By
testing the carry flag, this instruction determines whether R7 is greater or
less than 60H.
If the data being presented to port 1 is also 34H, then the instruction
WAIT:
CJNE
A,P1,WAIT
clears the carry flag and continues with the next instruction in sequence,
since the accumulator does equal the data read from P1. (If some other
value was input on P1, the program will loop at this point until the P1 data
changes to 34H).
User’s Manual
4-20
2000-07
C500
Instruction Set
CJNE
A,direct,rel
Operation:
(PC) ← (PC) + 3
if (A) < > (direct)
then (PC) ← (PC) + relative offset
if (A) < (direct)
then (C) ←1
else (C) ← 0
Encoding:
1 0 1 1 0 1 0 1
Bytes:
3
Cycles:
2
CJNE
A, #data,rel
Operation:
(PC) ← (PC) + 3
if (A) < > data
then (PC) ← (PC) + relative offset
if (A) ← data
then (C) ←1
else (C) ← 0
Encoding:
1 0 1 1 0 1 0 0
Bytes:
3
Cycles:
2
CJNE
RN, #data, rel
Operation:
(PC) ← (PC) + 3
if (Rn) < > data
then (PC) ← (PC) + relative offset
if (Rn) < data
then (C) ← 1
else (C) ← 0
Encoding:
1 0 1 1 1 r r r
Bytes:
3
Cycles:
2
User’s Manual
direct address
immediate data
immediate data
4-21
rel. address
rel. address
rel. address
2000-07
C500
Instruction Set
CJNE
@Ri, #data, rel
Operation:
(PC) ← (PC) + 3
if ((Ri)) < > data
then (PC) ← (PC) + relative offset
if ((Ri)) < data
then (C) ← 1
else (C) ← 0
Encoding:
1 0 1 1 0 1 1 i
Bytes:
3
Cycles:
2
CLR
A
Function:
Clear accumulator
Description:
The accumulator is cleared (all bits set to zero). No flags are affected.
Example:
The accumulator contains 5CH (01011100B). The instruction
CLR
immediate data
rel. address
A
will leave the accumulator set to 00H (00000000B).
Operation:
CLR
(A) ← 0
Encoding:
1 1 1 0 0 1 0 0
Bytes:
1
Cycles:
1
User’s Manual
4-22
2000-07
C500
Instruction Set
CLR
bit
Function:
Clear bit
Description:
The indicated bit is cleared (reset to zero). No other flags are affected.
CLR can operate on the carry flag or any directly addressable bit.
Example:
Port 1 has previously been written with 5DH (01011101B). The instruction
CLR
P1.2
will leave the port set to 59H (01011001B).
CLR
C
Operation:
CLR
(C) ← 0
Encoding:
1 1 0 0 0 0 1 1
Bytes:
1
Cycles:
1
CLR
bit
Operation:
CLR
(bit) ← 0
Encoding:
1 1 0 0 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
bit address
4-23
2000-07
C500
Instruction Set
CPL
A
Function:
Complement accumulator
Description:
Each bit of the accumulator is logically complemented (one’s
complement). Bits which previously contained a one are changed to zero
and vice versa. No flags are affected.
Example:
The accumulator contains 5CH (01011100B). The instruction
CPL
A
will leave the accumulator set to 0A3H (10100011B).
Operation:
CPL
(A) ← / (A)
Encoding:
1 1 1 1 0 1 0 0
Bytes:
1
Cycles:
1
User’s Manual
4-24
2000-07
C500
Instruction Set
CPL
bit
Function:
Complement bit
Description:
The bit variable specified is complemented. A bit which had been a one is
changed to zero and vice versa. No other flags are affected. CPL can
operate on the carry or any directly addressable bit.
Note:
When this instruction is used to modify an output pin, the value used as
the original data will be read from the output data latch, not the input pin.
Example:
Port 1 has previously been written with 5DH (01011101B). The instruction
sequence
CPL
CPL
P1.1
P1.2
will leave the port set to 5BH (01011011B).
CPL
C
Operation:
CPL
(bit) ← / (C)
Encoding:
1 0 1 1 0 0 1 1
Bytes:
1
Cycles:
1
CPL
bit
Operation:
CPL
(C) ← (bit)
Encoding:
1 0 1 1 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
bit address
4-25
2000-07
C500
Instruction Set
DA
A
Function:
Decimal adjust accumulator for addition
Description:
DA A adjusts the eight-bit value in the accumulator resulting from the
earlier addition of two variables (each in packed BCD format), producing
two four-bit digits. Any ADD or ADDC instruction may have been used to
perform the addition.
If accumulator bits 3-0 are greater than nine (xxxx1010-xxxx1111), or if
the AC flag is one, six is added to the accumulator producing the proper
BCD digit in the low-order nibble. This internal addition would set the carry
flag if a carry-out of the low-order four-bit field propagated through all highorder bits, but it would not clear the carry flag otherwise.
If the carry flag is now set, or if the four high-order bits now exceed nine
(1010xxxx-1111xxxx), these high-order bits are incremented by six,
producing the proper BCD digit in the high-order nibble. Again, this would
set the carry flag if there was a carry-out of the high-order bits, but
wouldn’t clear the carry. The carry flag thus indicates if the sum of the
original two BCD variables is greater than 100, allowing multiple precision
decimal addition. OV is not affected.
All of this occurs during the one instruction cycle. Essentially; this
instruction performs the decimal conversion by adding 00H, 06H, 60H, or
66H to the accumulator, depending on initial accumulator and PSW
conditions.
Note:
DA A cannot simply convert a hexadecimal number in the accumulator to
BCD notation, nor does DA A apply to decimal subtraction.
Example:
The accumulator holds the value 56H (01010110B) representing the
packed BCD digits of the decimal number 56. Register 3 contains the
value 67H (01100111B) representing the packed BCD digits of the decimal
number 67. The carry flag is set. The instruction sequence
ADDC
DA
A,R3
A
will first perform a standard two’s-complement binary addition, resulting in
the value 0BEH (10111110B) in the accumulator. The carry and auxiliary
carry flags will be cleared.
The decimal adjust instruction will then alter the accumulator to the value
24H (00100100B), indicating the packed BCD digits of the decimal number
24, the low-order two digits of the decimal sum of 56, 67, and the carry-in.
The carry flag will be set by the decimal adjust instruction, indicating that
a decimal overflow occurred. The true sum 56, 67, and 1 is 124.
User’s Manual
4-26
2000-07
C500
Instruction Set
BCD variables can be incremented or decremented by adding 01H or 99H.
If the accumulator initially holds 30H (representing the digits of 30
decimal), then the instruction sequence
ADD
DA
A, #99H
A
will leave the carry set and 29H in the accumulator, since 30 + 99 = 129.
The low-order byte of the sum can be interpreted to mean 30 – 1 = 29.
Operation:
DA
contents of accumulator are BCD
if [[(A3-0) > 9] ∨ [(AC) = 1]]
then (A3-0) ← (A3-0) + 6
and
if [[(A7-4) > 9] ∨ [(C) = 1]]
then (A7-4) ← (A7-4) + 6
Encoding:
1 1 0 1 0 1 0 0
Bytes:
1
Cycles:
1
User’s Manual
4-27
2000-07
C500
Instruction Set
DEC
byte
Function:
Decrement
Description:
The variable indicated is decremented by 1. An original value of 00H will
underflow to 0FFH. No flags are affected. Four operand addressing
modes are allowed: accumulator, register, direct, or register-indirect.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
Register 0 contains 7FH (01111111B). Internal RAM locations 7EH and
7FH contain 00H and 40H, respectively. The instruction sequence
DEC
DEC
DEC
@R0
R0
@R0
will leave register 0 set to 7EH and internal RAM locations 7EH and 7FH
set to 0FFH and 3FH.
DEC
A
Operation:
DEC
(A) ← (A) – 1
Encoding:
0 0 0 1 0 1 0 0
Bytes:
1
Cycles:
1
DEC
Rn
Operation:
DEC
(Rn) ← (Rn) – 1
Encoding:
0 0 0 1 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-28
2000-07
C500
Instruction Set
DEC
direct
Operation:
DEC
(direct) ← (direct) – 1
Encoding:
0 0 0 1 0 1 0 1
Bytes:
2
Cycles:
1
DEC
@Ri
Operation:
DEC
((Ri)) ← ((Ri)) – 1
Encoding:
0 0 0 1 0 1 1 i
Bytes:
1
Cycles:
1
User’s Manual
direct address
4-29
2000-07
C500
Instruction Set
DIV
AB
Function:
Divide
Description:
DIV AB divides the unsigned eight-bit integer in the accumulator by the
unsigned eight-bit integer in register B. The accumulator receives the
integer part of the quotient; register B receives the integer remainder. The
carry and OV flags will be cleared.
Exception: If B had originally contained 00H, the values returned in the
accumulator and B register will be undefined and the overflow flag will be
set. The carry flag is cleared in any case.
Example:
The accumulator contains 251 (0FBH or 11111011B) and B contains 18
(12H or 00010010B). The instruction
DIV
AB
will leave 13 in the accumulator (0DH or 00001101B) and the value 17
(11H or 00010001B) in B, since 251 = (13 × 18) + 17. Carry and OV will
both be cleared.
Operation:
DIV
(A15-8)
(B7-0)
← (A) / (B)
Encoding:
1 0 0 0 0 1 0 0
Bytes:
1
Cycles:
4
User’s Manual
4-30
2000-07
C500
Instruction Set
DJNZ
<byte>, <rel-addr>
Function:
Decrement and jump if not zero
Description:
DJNZ decrements the location indicated by 1, and branches to the
address indicated by the second operand if the resulting value is not zero.
An original value of 00H will underflow to 0FFH. No flags are affected. The
branch destination would be computed by adding the signed relativedisplacement value in the last instruction byte to the PC, after
incrementing the PC to the first byte of the following instruction.
The location decremented may be a register or directly addressed byte.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
Internal RAM locations 40H, 50H, and 60H contain the values, 01H, 70H,
and 15H, respectively. The instruction sequence
DJNZ 40H,LABEL_1
DJNZ 50H,LABEL_2
DJNZ 60H,LABEL_3
will cause a jump to the instruction at label LABEL_2 with the values 00 H,
6FH, and 15H in the three RAM locations. The first jump was not taken
because the result was zero.
This instruction provides a simple way of executing a program loop a
given number of times, or for adding a moderate time delay (from 2 to
512 machine cycles) with a single instruction. The instruction sequence
TOGGLE:
MOV
CPL
DJNZ
R2, #8
P1.7
R2,TOGGLE
will toggle P1.7 eight times, causing four output pulses to appear at bit 7
of output port 1. Each pulse will last three machine cycles; two for DJNZ
and one to alter the pin.
User’s Manual
4-31
2000-07
C500
Instruction Set
DJNZ
Rn,rel
Operation:
DJNZ
(PC) ← (PC) + 2
(Rn) ← (Rn) – 1
if (Rn) > 0 or (Rn) < 0
then (PC) ← (PC) + rel
Encoding:
1 1 0 1 1 r r r
Bytes:
2
Cycles:
2
DJNZ
direct,rel
Operation:
DJNZ
(PC) ← (PC) + 2
(direct) ← (direct) – 1
if (direct) > 0 or (direct) < 0
then (PC) ← (PC) + rel
Encoding:
1 1 0 1 0 1 0 1
Bytes:
3
Cycles:
2
User’s Manual
rel. address
direct address
4-32
rel. address
2000-07
C500
Instruction Set
INC
<byte>
Function:
Increment
Description:
INC increments the indicated variable by 1. An original value of 0FFH will
overflow to 00H. No flags are affected. Three addressing modes are
allowed: register, direct, or register-indirect.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
Register 0 contains 7EH (01111110B). Internal RAM locations 7EH and
7FH contain 0FFH and 40H, respectively. The instruction sequence
INC
INC
INC
@R0
R0
@R0
will leave register 0 set to 7FH and internal RAM locations 7EH and 7FH
holding (respectively) 00H and 41H.
INC
A
Operation:
INC
(A) ← (A) + 1
Encoding:
0 0 0 0 0 1 0 0
Bytes:
1
Cycles:
1
INC
Rn
Operation:
INC
(Rn) ← (Rn) + 1
Encoding:
0 0 0 0 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-33
2000-07
C500
Instruction Set
INC
direct
Operation:
INC
(direct) ← (direct) + 1
Encoding:
0 0 0 0 0 1 0 1
Bytes:
2
Cycles:
1
INC
@Ri
Operation:
INC
((Ri)) ← ((Ri)) + 1
Encoding:
0 0 0 0 0 1 1 i
Bytes:
1
Cycles:
1
User’s Manual
direct address
4-34
2000-07
C500
Instruction Set
INC
DPTR
Function:
Increment data pointer
Description:
Increment the 16-bit data pointer by 1. A 16-bit increment (modulo 2 16) is
performed; an overflow of the low-order byte of the data pointer (DPL)
from 0FFH to 00H will increment the high-order byte (DPH). No flags are
affected.
This is the only 16-bit register which can be incremented.
Example:
Registers DPH and DPL contain 12H and 0FEH, respectively. The
instruction sequence
INC
INC
INC
DPTR
DPTR
DPTR
will change DPH and DPL to 13H and 01H.
Operation:
INC
(DPTR) ← (DPTR) + 1
Encoding:
1 0 1 0 0 0 1 1
Bytes:
1
Cycles:
2
User’s Manual
4-35
2000-07
C500
Instruction Set
JB
bit,rel
Function:
Jump if bit is set
Description:
If the indicated bit is a one, jump to the address indicated; otherwise
proceed with the next instruction. The branch destination is computed by
adding the signed relative-displacement in the third instruction byte to the
PC, after incrementing the PC to the first byte of the next instruction. The
bit tested is not modified. No flags are affected.
Example:
The data present at input port 1 is 11001010B. The accumulator holds 56
(01010110B). The instruction sequence
JB
JB
P1.2,LABEL1
ACC.2,LABEL2
will cause program execution to branch to the instruction at label LABEL2.
Operation:
JB
(PC) ← (PC) + 3
if (bit) = 1
then (PC) ← (PC) + rel
Encoding:
0 0 1 0 0 0 0 0
Bytes:
3
Cycles:
2
User’s Manual
bit address
4-36
rel. address
2000-07
C500
Instruction Set
JBC
bit,rel
Function:
Jump if bit is set and clear bit
Description:
If the indicated bit is one, branch to the address indicated; otherwise
proceed with the next instruction. In either case, clear the designated bit.
The branch destination is computed by adding the signed relative
displacement in the third instruction byte to the PC, after incrementing the
PC to the first byte of the next instruction. No flags are affected.
Note:
When this instruction is used to test an output pin, the value used as the
original data will be read from the output data latch, not the input pin.
Example:
The accumulator holds 56H (01010110B). The instruction sequence
JBC
JBC
ACC.3,LABEL1
ACC.2,LABEL2
will cause program execution to continue at the instruction identified by
the label LABEL2, with the accumulator modified to 52H (01010010B).
Operation:
JBC
(PC) ← (PC) + 3
if (bit) = 1
then (bit) ← 0
(PC) ← (PC) + rel
Encoding:
0 0 0 1 0 0 0 0
Bytes:
3
Cycles:
2
User’s Manual
bit address
4-37
rel. address
2000-07
C500
Instruction Set
JC
rel
Function:
Jump if carry is set
Description:
If the carry flag is set, branch to the address indicated; otherwise proceed
with the next instruction. The branch destination is computed by adding
the signed relative-displacement in the second instruction byte to the PC,
after incrementing the PC twice. No flags are affected.
Example:
The carry flag is cleared. The instruction sequence
JC
CPL
JC
LABEL1
C
LABEL2
will set the carry and cause program execution to continue at the
instruction identified by the label LABEL2.
Operation:
JC
(PC) ← (PC) + 2
if (C) = 1
then (PC) ← (PC) + rel
Encoding:
0 1 0 0 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
rel. address
4-38
2000-07
C500
Instruction Set
JMP
@A + DPTR
Function:
Jump indirect
Description:
Add the eight-bit unsigned contents of the accumulator with the sixteenbit data pointer, and load the resulting sum to the program counter. This
will be the address for subsequent instruction fetches. Sixteen-bit addition
is performed (modulo 216): a carry-out from the low-order eight bits
propagates through the higher-order bits. Neither the accumulator nor the
data pointer is altered. No flags are affected.
Example:
An even number from 0 to 6 is in the accumulator. The following sequence
of instructions will branch to one of four AJMP instructions in a jump table
starting at JMP_TBL:
MOV
JMP
JMP_TBL: AJMP
AJMP
AJMP
AJMP
DPTR, #JMP_TBL
@A + DPTR
LABEL0
LABEL1
LABEL2
LABEL3
If the accumulator equals 04H when starting this sequence, execution will
jump to label LABEL2. Remember that AJMP is a two-byte instruction, so
the jump instructions start at every other address.
Operation:
JMP
(PC) ← (A) + (DPTR)
Encoding:
0 1 1 1 0 0 1 1
Bytes:
1
Cycles:
2
User’s Manual
4-39
2000-07
C500
Instruction Set
JNB
bit,rel
Function:
Jump if bit is not set
Description:
If the indicated bit is a zero, branch to the indicated address; otherwise
proceed with the next instruction. The branch destination is computed by
adding the signed relative-displacement in the third instruction byte to the
PC, after incrementing the PC to the first byte of the next instruction. The
bit tested is not modified. No flags are affected.
Example:
The data present at input port 1 is 11001010B. The accumulator holds 56H
(01010110B). The instruction sequence
JNB
JNB
P1.3,LABEL1
ACC.3,LABEL2
will cause program execution to continue at the instruction at label
LABEL2.
Operation:
JNB
(PC) ← (PC) + 3
if (bit) = 0
then (PC) ← (PC) + rel.
Encoding:
0 0 1 1 0 0 0 0
Bytes:
3
Cycles:
2
User’s Manual
bit address
4-40
rel. address
2000-07
C500
Instruction Set
JNC
rel
Function:
Jump if carry is not set
Description:
If the carry flag is a zero, branch to the address indicated; otherwise
proceed with the next instruction. The branch destination is computed by
adding the signed relative-displacement in the second instruction byte to
the PC, after incrementing the PC twice to point to the next instruction.
The carry flag is not modified.
Example:
The carry flag is set. The instruction sequence
JNC
CPL
JNC
LABEL1
C
LABEL2
will clear the carry and cause program execution to continue at the
instruction identified by the label LABEL2.
Operation:
JNC
(PC) ← (PC) + 2
if (C) = 0
then (PC) ← (PC) + rel
Encoding:
0 1 0 1 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
rel. address
4-41
2000-07
C500
Instruction Set
JNZ
rel
Function:
Jump if accumulator is not zero
Description:
If any bit of the accumulator is a one, branch to the indicated address;
otherwise proceed with the next instruction. The branch destination is
computed by adding the signed relative-displacement in the second
instruction byte to the PC, after incrementing the PC twice. The
accumulator is not modified. No flags are affected.
Example:
The accumulator originally holds 00H. The instruction sequence
JNZ
INC
JNZ
LABEL1
A
LABEL2
will set the accumulator to 01H and continue at label LABEL2.
Operation:
JNZ
(PC) ← (PC) + 2
if (A) ≠ 0
then (PC) ← (PC) + rel.
Encoding:
0 1 1 1 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
rel. address
4-42
2000-07
C500
Instruction Set
JZ
rel
Function:
Jump if accumulator is zero
Description:
If all bits of the accumulator are zero, branch to the address indicated;
otherwise proceed with the next instruction. The branch destination is
computed by adding the signed relative-displacement in the second
instruction byte to the PC, after incrementing the PC twice. The
accumulator is not modified. No flags are affected.
Example:
The accumulator originally contains 01H. The instruction sequence
JZ
DEC
JZ
LABEL1
A
LABEL2
will change the accumulator to 00H and cause program execution to
continue at the instruction identified by the label LABEL2.
Operation:
JZ
(PC) ← (PC) + 2
if (A) = 0
then (PC) ← (PC) + rel
Encoding:
0 1 1 0 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
rel. address
4-43
2000-07
C500
Instruction Set
LCALL
addr16
Function:
Long call
Description:
LCALL calls a subroutine located at the indicated address. The instruction
adds three to the program counter to generate the address of the next
instruction and then pushes the 16-bit result onto the stack (low byte first),
incrementing the stack pointer by two. The high-order and low-order bytes
of the PC are then loaded, respectively, with the second and third bytes
of the LCALL instruction. Program execution continues with the instruction
at this address. The subroutine may therefore begin anywhere in the full
64 Kbyte program memory address space. No flags are affected.
Example:
Initially the stack pointer equals 07H. The label “SUBRTN” is assigned to
program memory location 1234H. After executing the instruction
LCALL
SUBRTN
at location 0123H, the stack pointer will contain 09H, internal RAM
locations 08H and 09H will contain 26H and 01H, and the PC will contain
1234H.
Operation:
LCALL
(PC) ← (PC) + 3
(SP) ← (SP) + 1
((SP)) ← (PC7-0)
(SP) ← (SP) + 1
((SP)) ← (PC15-8)
(PC) ← addr15-0
Encoding:
0 0 0 1 0 0 1 0
Bytes:
3
Cycles:
2
User’s Manual
addr15 … addr8
4-44
addr7 … addr0
2000-07
C500
Instruction Set
LJMP
addr16
Function:
Long jump
Description:
LJMP causes an unconditional branch to the indicated address, by
loading the high-order and low-order bytes of the PC (respectively) with
the second and third instruction bytes. The destination may therefore be
anywhere in the full 64K program memory address space. No flags are
affected.
Example:
The label “JMPADR” is assigned to the instruction at program memory
location 1234H. The instruction
LJMP
JMPADR
at location 0123H will load the program counter with 1234H.
Operation:
LJMP
(PC) ← addr15-0
Encoding:
0 0 0 0 0 0 1 0
Bytes:
3
Cycles:
2
User’s Manual
addr15 … addr8
4-45
addr7 … addr0
2000-07
C500
Instruction Set
MOV
<dest-byte>, <src-byte>
Function:
Move byte variable
Description:
The byte variable indicated by the second operand is copied into the
location specified by the first operand. The source byte is not affected. No
other register or flag is affected.
This is by far the most flexible operation. Fifteen combinations of source
and destination addressing modes are allowed.
Example:
Internal RAM location 30H holds 40H. The value of RAM location 40H is
10H. The data present at input port 1 is 11001010B (0CAH).
MOV
MOV
MOV
MOV
MOV
MOV
R0, #30H ;
A, @R0 ;
R1,A
;
B, @R1 ;
@R1,P1 ;
P2,P1
;
R0 < = 30H
A < = 40H
R1 < = 40H
B < = 10H
RAM (40H) < = 0CAH
P2 < = 0CAH
leaves the value 30H in register 0, 40H in both the accumulator and
register 1, 10H in register B, and 0CAH (11001010B) both in RAM location
40H and output on port 2.
MOV
A,Rn
Operation:
MOV
(A) ← (Rn)
Encoding:
1 1 1 0 1 r r r
Bytes:
1
Cycles:
1
MOV
A,direct1)
Operation:
MOV
(A) ← (direct)
Encoding:
1 1 1 0 0 1 0 1
Bytes:
2
Cycles:
1
1)
direct address
MOV A,ACC is not a valid instruction. The content of the accumulator after the execution of this instruction is
undefined.
User’s Manual
4-46
2000-07
C500
Instruction Set
MOV
A,@Ri
Operation:
MOV
(A) ← ((Ri))
Encoding:
1 1 1 0 0 1 1 i
Bytes:
1
Cycles:
1
MOV
A, #data
Operation:
MOV
(A) ← #data
Encoding:
0 1 1 1 0 1 0 0
Bytes:
2
Cycles:
1
MOV
Rn,A
Operation:
MOV
(Rn) ← (A)
Encoding:
1 1 1 1 1 r r r
Bytes:
1
Cycles:
1
MOV
Rn,direct
Operation:
MOV
(Rn) ← (direct)
Encoding:
1 0 1 0 1 r r r
Bytes:
2
Cycles:
2
User’s Manual
immediate data
direct address
4-47
2000-07
C500
Instruction Set
MOV
Rn, #data
Operation:
MOV
(Rn) ← #data
Encoding:
0 1 1 1 1 r r r
Bytes:
2
Cycles:
1
MOV
direct,A
Operation:
MOV
(direct) ← (A)
Encoding:
1 1 1 1 0 1 0 1
Bytes:
2
Cycles:
1
MOV
direct,Rn
Operation:
MOV
(direct) ← (Rn)
Encoding:
1 0 0 0 1 r r r
Bytes:
2
Cycles:
2
MOV
direct,direct
Operation:
MOV
(direct) ← (direct)
Encoding:
1 0 0 0 0 1 0 1
Bytes:
3
Cycles:
2
User’s Manual
immediate data
direct address
direct address
dir.addr. (src)
4-48
dir.addr. (dest)
2000-07
C500
Instruction Set
MOV
direct, @ Ri
Operation:
MOV
(direct) ← ((Ri))
Encoding:
1 0 0 0 0 1 1 i
Bytes:
2
Cycles:
2
MOV
direct, #data
Operation:
MOV
(direct) ← #data
Encoding:
0 1 1 1 0 1 0 1
Bytes:
3
Cycles:
2
MOV
@ Ri,A
Operation:
MOV
((Ri)) ← (A)
Encoding:
1 1 1 1 0 1 1 i
Bytes:
1
Cycles:
1
MOV
@ Ri,direct
Ooeration:
MOV
((Ri)) ← (direct)
Encoding:
1 0 1 0 0 1 1 i
Bytes:
2
Cycles:
2
User’s Manual
direct address
direct address
immediate data
direct address
4-49
2000-07
C500
Instruction Set
MOV
@ Ri,#data
Operation:
MOV
((Ri)) ← #data
Encoding:
0 1 1 1 0 1 1 i
Bytes:
2
Cycles:
1
User’s Manual
immediate data
4-50
2000-07
C500
Instruction Set
MOV
<dest-bit>, <src-bit>
Function:
Move bit data
Description:
The Boolean variable indicated by the second operand is copied into the
location specified by the first operand. One of the operands must be the
carry flag; the other may be any directly addressable bit. No other register
or flag is affected.
Example:
The carry flag is originally set. The data present at input port 3 is
11000101B. The data previously written to output port 1 is 35H
(00110101B).
MOV
MOV
MOV
P1.3,C
C,P3.3
P1.2,C
will leave the carry cleared and change port 1 to 39H (00111001B).
MOV
C,bit
Operation:
MOV
(C) ← (bit)
Encoding:
1 0 1 0 0 0 1 0
Bytes:
2
Cycles:
1
MOV
bit,C
Operation:
MOV
(bit) ← (C)
Encoding:
1 0 0 1 0 0 1 0
Bytes:
2
Cycles:
2
User’s Manual
bit address
bit address
4-51
2000-07
C500
Instruction Set
MOV
DPTR, #data16
Function:
Load data pointer with a 16-bit constant
Description:
The data pointer is loaded with the 16-bit constant indicated. The 16 bit
constant is loaded into the second and third bytes of the instruction. The
second byte (DPH) is the high-order byte, while the third byte (DPL) holds
the low-order byte. No flags are affected.
This is the only instruction which moves 16 bits of data at once.
Example:
The instruction
MOV
DPTR, #1234H
will load the value 1234H into the data pointer: DPH will hold 12H and DPL
will hold 34H.
Operation:
MOV
(DPTR) ← #data15-0
DPH DPL ← #data15-8
Encoding:
1 0 0 1 0 0 0 0
Bytes:
3
Cycles:
2
User’s Manual
#data7-0
immed. data 15 … 8
4-52
immed. data 7 … 0
2000-07
C500
Instruction Set
MOVC
A, @A + <base-reg>
Function:
Move code byte
Description:
The MOVC instructions load the accumulator with a code byte, or
constant from program memory. The address of the byte fetched is the
sum of the original unsigned eight-bit accumulator contents and the
contents of a sixteen-bit base register, which may be either the data
pointer or the PC. In the latter case, the PC is incremented to the address
of the following instruction before being added to the accumulator;
otherwise the base register is not altered. Sixteen-bit addition is
performed so a carry-out from the low-order eight bits may propagate
through higher-order bits. No flags are affected.
Example:
A value between 0 and 3 is in the accumulator. The following instructions
will translate the value in the accumulator to one of four values defined by
the DB (define byte) directive.
REL_PC:
INC
MOVC
RET
DB
DB
DB
DB
A
A, @A + PC
66H
77H
88H
99H
If the subroutine is called with the accumulator equal to 01H, it will return
with 77H in the accumulator. The INC A before the MOVC instruction is
needed to “get around” the RET instruction above the table. If several
bytes of code separated the MOVC from the table, the corresponding
number would be added to the accumulator instead.
MOVC
A, @A + DPTR
Operation:
MOVC
(A) ← ((A) + (DPTR))
Encoding:
1 0 0 1 0 01 1
Bytes:
1
Cycles:
2
User’s Manual
4-53
2000-07
C500
Instruction Set
MOVC
A, @A + PC
Operation:
MOVC
(PC) ← (PC) + 1
(A) ← ((A) + (PC))
Encoding:
1 0 0 0 0 01 1
Bytes:
1
Cycles:
2
User’s Manual
4-54
2000-07
C500
Instruction Set
MOVX
<dest-byte>, <src-byte>
Function:
Move external
Description:
The MOVX instructions transfer data between the accumulator and a byte
of external data memory, hence the “X” appended to MOV. There are two
types of instructions, differing in whether they provide an eight bit or
sixteen-bit indirect address to the external data RAM.
In the first type, the contents of R0 or R1 in the current register bank
provide an eight-bit address multiplexed with data on P0. Eight bits are
sufficient for external l/O expansion decoding or a relatively small RAM
array. For somewhat larger arrays, any output port pins can be used to
output higher-order address bits. These pins would be controlled by an
output instruction preceding the MOVX.
In the second type of MOVX instructions, the data pointer generates a
sixteen-bit address. P2 outputs the high-order eight address bits (the
contents of DPH) while P0 multiplexes the low-order eight bits (DPL) with
data. The P2 special function register retains its previous contents while
the P2 output buffers are emining the contents of DPH. This form is faster
and more efficient when accessing very large data arrays (up to 64 Kbyte),
since no additional instructions are needed to set up the output ports.
It is possible in some situations to mix the two MOVX types. A large RAM
array with its high-order address lines driven by P2 can be addressed via
the data pointer, or with code to output high-order address bits to P2
followed by a MOVX instruction using R0 or R1.
Example:
An external 256-byte RAM using multiplexed address/data lines is
connected to the C500 port 0. Port 3 provides control lines for the external
RAM. Ports 1 and 2 are used for normal l/O. Registers 0 and 1 contain 12H
and 34H. Location 34H of the external RAM holds the value 56H. The
instruction sequence
MOVX
MOVX
A, @R1
@R0,A
copies the value 56H into both the accumulator and external RAM location
12H.
User’s Manual
4-55
2000-07
C500
Instruction Set
MOVX
A,@Ri
Operation:
MOVX
(A) ← ((Ri))
Encoding:
1 1 1 0 0 0 1 i
Bytes:
1
Cycles:
2
MOVX
A,@DPTR
Operation:
MOVX
(A) ← ((DPTR))
Encoding:
1 1 1 0 0 0 0 0
Bytes:
1
Cycles:
2
MOVX
@Ri,A
Operation:
MOVX
((Ri)) ← (A)
Encoding:
1 1 1 1 0 0 1 i
Bytes:
1
Cycles:
2
MOVX
@DPTR,A
Operation:
MOVX
((DPTR))
(A)
Encoding:
1 1 1 1 0 0 0 0
Bytes:
1
Cycles:
2
User’s Manual
4-56
2000-07
C500
Instruction Set
MUL
AB
Function:
Multiply
Description:
MUL AB multiplies the unsigned eight-bit integers in the accumulator and
register B. The low-order byte of the sixteen-bit product is left in the
accumulator, and the high-order byte in B. If the product is greater than
255 (0FFH) the overflow flag is set; otherwise it is cleared. The carry flag
is always cleared.
Example:
Originally the accumulator holds the value 80 (50H). Register B holds the
value 160 (0A0H). The instruction
MUL
AB
will give the product 12,800 (3200H), so B is changed to 32H (00110010B)
and the accumulator is cleared. The overflow flag is set, carry is cleared.
Operation:
MUL
(A7-0)
(B15-8)
← (A) × (B)
Encoding:
1 0 1 0 0 1 0 0
Bytes:
1
Cycles:
4
User’s Manual
4-57
2000-07
C500
Instruction Set
NOP
Function:
No operation
Description:
Execution continues at the following instruction. Other than the PC, no
registers or flags are affected.
Example:
It is desired to produce a low-going output pulse on bit 7 of port 2 lasting
exactly 5 cycles. A simple SETB/CLR sequence would generate a
one-cycle pulse, so four additional cycles must be inserted. This may be
done (assuming no interrupts are enabled) with the instruction sequence
CLR
NOP
NOP
NOP
NOP
SETB
P2.7
P2.7
Operation:
NOP
Encoding:
0 0 0 0 0 0 0 0
Bytes:
1
Cycles:
1
User’s Manual
4-58
2000-07
C500
Instruction Set
ORL
<dest-byte>, <src-byte>
Function:
Logical OR for byte variables
Description:
ORL performs the bitwise logical OR operation between the indicated
variables, storing the results in the destination byte. No flags are affected
(except P, if <dest-byte> = A).
The two operands allow six addressing mode combinations. When the
destination is the accumulator, the source can use register, direct,
register-indirect, or immediate addressing; when the destination is a direct
address, the source can be the accumulator or immediate data.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
If the accumulator holds 0C3H (11000011B) and R0 holds 55H
(01010101B) then the instruction
ORL
A,R0
will leave the accumulator holding the value 0D7H (11010111B).
When the destination is a directly addressed byte, the instruction can set
combinations of bits in any RAM location or hardware register. The
pattern of bits to be set is determined by a mask byte, which may be either
a constant data value in the instruction or a variable computed in the
accumulator at run-time. The instruction
ORL
P1,#00110010B
will set bits 5, 4, and 1 of output port 1.
ORL
A,Rn
Operation:
ORL
(A) ← (A) ∨ (Rn)
Encoding:
0 1 0 0 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-59
2000-07
C500
Instruction Set
ORL
A,direct
Operation:
ORL
(A) ← (A) ∨ (direct)
Encoding:
0 1 0 0 0 1 0 1
Bytes:
2
Cycles:
1
ORL
A,@Ri
Operation:
ORL
(A) ← (A) ∨ ((Ri))
Encoding:
0 1 0 0 0 1 1 i
Bytes:
1
Cycles:
1
ORL
A,#data
Operation:
ORL
(A) ← (A) ∨ #data
Encoding:
0 1 0 0 0 1 0 0
Bytes:
2
Cycles:
1
ORL
direct,A
Operation:
ORL
(direct) ← (direct) ∨ (A)
Encoding:
0 1 0 0 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
direct address
immediate data
direct address
4-60
2000-07
C500
Instruction Set
ORL
direct, #data
Operation:
ORL
(direct) ← (direct) ∨ #data
Encoding:
0 1 0 0 0 0 1 1
Bytes:
3
Cycles:
2
User’s Manual
direct address
4-61
immediate data
2000-07
C500
Instruction Set
ORL
C, <src-bit>
Function:
Logical OR for bit variables
Description:
Set the carry flag if the Boolean value is a logic 1; leave the carry in its
current state otherwise. A slash (“/”) preceding the operand in the
assembly language indicates that the logical complement of the
addressed bit is used as the source value, but the source bit itself is not
affected. No other flags are affected.
Example:
Set the carry flag if, and only if, P1.0 = 1, ACC.7 = 1, or OV = 0:
MOV
ORL
ORL
C,P1.0 ; Load carry with input pin P1.0
C,ACC.7 ; OR carry with the accumulator bit 7
C,/OV
; OR carry with the inverse of OV
ORL
C,bit
Operation:
ORL
(C) ← (C) ∨ (bit)
Encoding:
0 1 1 1 0 0 1 0
Bytes:
2
Cycles:
2
ORL
C,/bit
Operation:
ORL
(C) ← (C) ∨ / (bit)
Encoding:
1 0 1 0 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
bit address
bit address
4-62
2000-07
C500
Instruction Set
POP
direct
Function:
Pop from stack
Description:
The contents of the internal RAM location addressed by the stack pointer
is read, and the stack pointer is decremented by one. The value read is
the transfer to the directly addressed byte indicated. No flags are affected.
Example:
The stack pointer originally contains the value 32H, and internal RAM
locations 30H through 32H contain the values 20H, 23H, and 01H,
respectively. The instruction sequence
POP
POP
DPH
DPL
will leave the stack pointer equal to the value 30H and the data pointer set
to 0123H. At this point the instruction
POP
SP
will leave the stack pointer set to 20H. Note that in this special case the
stack pointer was decremented to 2FH before being loaded with the value
popped (20H).
Operation:
POP
(direct) ← ((SP))
(SP) ← (SP) – 1
Encoding:
1 1 0 1 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
direct address
4-63
2000-07
C500
Instruction Set
PUSH
direct
Function:
Push onto stack
Description:
The stack pointer is incremented by one. The contents of the indicated
variable is then copied into the internal RAM location addressed by the
stack pointer. Otherwise no flags are affected.
Example:
On entering an interrupt routine the stack pointer contains 09H. The data
pointer holds the value 0123H. The instruction sequence
PUSH
PUSH
DPL
DPH
will leave the stack pointer set to 0BH and store 23H and 01H in internal
RAM locations 0AH and 0BH, respectively.
Operation:
PUSH
(SP) ← (SP) + 1
((SP)) ← (direct)
Encoding:
1 1 0 0 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
direct address
4-64
2000-07
C500
Instruction Set
RET
Function:
Return from subroutine
Description:
RET pops the high and low-order bytes of the PC successively from the
stack, decrementing the stack pointer by two. Program execution
continues at the resulting address, generally the instruction immediately
following an ACALL or LCALL. No flags are affected.
Example:
The stack pointer originally contains the value 0BH. Internal RAM
locations 0AH and 0BH contain the values 23H and 01H, respectively. The
instruction
RET
will leave the stack pointer equal to the value 09H. Program execution will
continue at location 0123H.
Operation:
RET
(PC15-8) ← ((SP))
(SP) ← (SP) – 1
(PC7-0) ← ((SP))
(SP) ← (SP) – 1
Encoding:
0 0 1 0 0 0 1 0
Bytes:
1
Cycles:
2
User’s Manual
4-65
2000-07
C500
Instruction Set
RETI
Function:
Return from interrupt
Description:
RETI pops the high and low-order bytes of the PC successively from the
stack, and restores the interrupt logic to accept additional interrupts at the
same priority level as the one just processed. The stack pointer is left
decremented by two. No other registers are affected; the PSW is not
automatically restored to its pre-interrupt status. Program execution
continues at the resulting address, which is generally the instruction
immediately after the point at which the interrupt request was detected. If
a lower or same-level interrupt is pending when the RETI instruction is
executed, that one instruction will be executed before the pending
interrupt is processed.
Example:
The stack pointer originally contains the value 0BH. An interrupt was
detected during the instruction ending at location 0122H. Internal RAM
locations 0AH and 0BH contain the values 23H and 01H, respectively. The
instruction
RETI
will leave the stack pointer equal to 09H and return program execution to
location 0123H.
Operation:
RETI
(PC15-8) ← ((SP))
(SP) ← (SP) – 1
(PC7-0) ← ((SP))
(SP) ← (SP) – 1
Encoding:
0 0 1 1 0 0 1 0
Bytes:
1
Cycles:
2
User’s Manual
4-66
2000-07
C500
Instruction Set
RL
A
Function:
Rotate accumulator left
Description:
The eight bits in the accumulator are rotated one bit to the left. Bit 7 is
rotated into the bit 0 position. No flags are affected.
Example:
The accumulator holds the value 0C5H (11000101B). The instruction
RL
A
leaves the accumulator holding the value 8BH (10001011B) with the carry
unaffected.
Operation:
RL
(An + 1) ← (An) n = 0-6
(A0) ← (A7)
Encoding:
0 0 1 0 0 0 1 1
Bytes:
1
Cycles:
1
User’s Manual
4-67
2000-07
C500
Instruction Set
RLC
A
Function:
Rotate accumulator left through carry flag
Description:
The eight bits in the accumulator and the carry flag are together rotated
one bit to the left. Bit 7 moves into the carry flag; the original state of the
carry flag moves into the bit 0 position. No other flags are affected.
Example:
The accumulator holds the value 0C5H (11000101B), and the carry is
zero. The instruction
RLC
A
leaves the accumulator holding the value 8AH (10001010B) with the carry
set.
Operation:
RLC
(An + 1) ← (An) n = 0-6
(A0) ← (C)
(C) ← (A7)
Encoding:
0 0 1 1 0 0 1 1
Bytes:
1
Cycles:
1
User’s Manual
4-68
2000-07
C500
Instruction Set
RR
A
Function:
Rotate accumulator right
Description:
The eight bits in the accumulator are rotated one bit to the right. Bit 0 is
rotated into the bit 7 position. No flags are affected.
Example:
The accumulator holds the value 0C5H (11000101B). The instruction
RR
A
leaves the accumulator holding the value 0E2H (11100010B) with the
carry unaffected.
Operation:
RR
(An) ← (An + 1) n = 0-6
(A7) ← (A0)
Encoding:
0 0 0 0 0 0 1 1
Bytes:
1
Cycles:
1
User’s Manual
4-69
2000-07
C500
Instruction Set
RRC
A
Function:
Rotate accumulator right through carry flag
Description:
The eight bits in the accumulator and the carry flag are together rotated
one bit to the right. Bit 0 moves into the carry flag; the original value of the
carry flag moves into the bit 7 position. No other flags are affected.
Example:
The accumulator holds the value 0C5H (11000101B), the carry is zero.
The instruction
RRC
A
leaves the accumulator holding the value 62H (01100010B) with the carry
set.
Operation:
RRC
(An) ← (An + 1) n = 0-6
(A7) ← (C)
(C) ← (A0)
Encoding:
0 0 0 1 0 0 1 1
Bytes:
1
Cycles:
1
User’s Manual
4-70
2000-07
C500
Instruction Set
SETB
<bit>
Function:
Set bit
Description:
SETB sets the indicated bit to one. SETB can operate on the carry flag or
any directiy addressable bit. No other flags are affected.
Example:
The carry flag is cleared. Output port 1 has been written with the value 34H
(00110100B). The instructions
SETB
SETB
C
P1.0
will leave the carry flag set to 1 and change the data output on port 1 to
35H (00110101B).
SETB
C
Operation:
SETB
(C) ← 1
Encoding:
1 1 0 1 0 0 1 1
Bytes:
1
Cycles:
1
SETB
bit
Operation:
SETB
(bit) ← 1
Encoding:
1 1 0 1 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
bit address
4-71
2000-07
C500
Instruction Set
SJMP
rel
Function:
Short jump
Description:
Program control branches unconditionally to the address indicated. The
branch destination is computed by adding the signed displacement in the
second instruction byte to the PC, after incrementing the PC twice.
Therefore, the range of destinations allowed is from 128 bytes preceding
this instruction to 127 bytes following it.
Example:
The label “RELADR” is assigned to an instruction at program memory
location 0123H. The instruction
SJMP
RELADR
will assemble into location 0100H. After the instruction is executed, the PC
will contain the value 0123H.
Note:
Under the above conditions the instruction following SJMP will be at 102H.
Therefore, the displacement byte of the instruction will be the relative
offset (0123H – 0102H) = 21H. In other words, an SJMP with a
displacement of 0FEH would be a one-instruction infinite loop.
Operation:
SJMP
(PC) ← (PC) + 2
(PC) ← (PC) + rel
Encoding:
1 0 0 0 0 0 0 0
Bytes:
2
Cycles:
2
User’s Manual
rel. address
4-72
2000-07
C500
Instruction Set
SUBB
A, <src-byte>
Function:
Subtract with borrow
Description:
SUBB subtracts the indicated variable and the carry flag together from the
accumulator, leaving the result in the accumulator. SUBB sets the carry
(borrow) flag if a borrow is needed for bit 7, and clears C otherwise. (If C
was set before executing a SUBB instruction, this indicates that a borrow
was needed for the previous step in a multiple precision subtraction, so
the carry is subtracted from the accumulator along with the source
operand). AC is set if a borrow is needed for bit 3, and cleared otherwise.
OV is set if a borrow is needed into bit 6 but not into bit 7, or into bit 7 but
not bit 6.
When subtracting signed integers OV indicates a negative number
produced when a negative value is subtracted from a positive value, or a
positive result when a positive number is subtracted from a negative
number.
The source operand allows four addressing modes: register, direct,
register-indirect, or immediate.
Example:
The accumulator holds 0C9H (11001001B), register 2 holds 54H
(01010100B), and the carry flag is set. The instruction
SUBB
A,R2
will leave the value 74H (01110100B) in the accumulator, with the carry
flag and AC cleared but OV set.
Notice that 0C9H minus 54H is 75H. The difference between this and the
above result is due to the (borrow) flag being set before the operation. If
the state of the carry is not known before starting a single or multipleprecision subtraction, it should be explicitly cleared by a CLR C
instruction.
SUBB
A,Rn
Operation:
SUBB
(A) ← (A) – (C) – (Rn)
Encoding:
1 0 0 1 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-73
2000-07
C500
Instruction Set
SUBB
A,direct
Operation:
SUBB
(A) ← (A) – (C) – (direct)
Encoding:
1 0 0 1 0 1 0 1
Bytes:
2
Cycles:
1
SUBB
A, @ Ri
Operation:
SUBB
(A) ← (A) – (C) – ((Ri))
Encoding:
1 0 0 1 0 1 1 i
Bytes:
1
Cycles:
1
SUBB
A, #data
Operation:
SUBB
(A) ← (A) – (C) – #data
Encoding:
1 0 0 1 0 1 0 0
Bytes:
2
Cycles:
1
User’s Manual
direct address
immediate data
4-74
2000-07
C500
Instruction Set
SWAP
A
Function:
Swap nibbles within the accumulator
Description:
SWAP A interchanges the low and high-order nibbles (four-bit fields) of
the accumulator (bits 3-0 and bits 7-4). The operation can also be thought
of as a four-bit rotate instruction. No flags are affected.
Example:
The accumulator holds the value 0C5H (11000101B). The instruction
SWAP
A
leaves the accumulator holding the value 5CH (01011100B).
Operation:
SWAP
(A3-0) ←
→ (A7-4), (A7-4) ← (A3-0)
Encoding:
1 1 0 0 0 1 0 0
Bytes:
1
Cycles:
1
User’s Manual
4-75
2000-07
C500
Instruction Set
XCH
A, <byte>
Function:
Exchange accumulator with byte variable
Description:
XCH loads the accumulator with the contents of the indicated variable, at
the same time writing the original accumulator contents to the indicated
variable. The source/destination operand can use register, direct, or
register-indirect addressing.
Example:
R0 contains the address 20H. The accumulator holds the value 3FH
(00111111B). Internal RAM location 20H holds the value 75H
(01110101B). The instruction
XCH
A, @R0
will leave RAM location 20H holding the value 3FH (00111111B) and 75H
(01110101B) in the accumulator.
XCH
A,Rn
Operation:
XCH
(A) ←
→ (Rn)
Encoding:
1 1 0 0 1 r r r
Bytes:
1
Cycles:
1
XCH
A,direct
Operation:
XCH
(A) ←
→ (direct)
Encoding:
1 1 0 0 0 1 0 1
Bytes:
2
Cycles:
1
User’s Manual
direct address
4-76
2000-07
C500
Instruction Set
XCH
A, @ Ri
Operation:
XCH
(A) ←
→ ((Ri))
Encoding:
1 1 0 0 0 1 1 i
Bytes:
1
Cycles:
1
User’s Manual
4-77
2000-07
C500
Instruction Set
XCHD
A,@Ri
Function:
Exchange digit
Description:
XCHD exchanges the low-order nibble of the accumulator (bits 3-0,
generally representing a hexadecimal or BCD digit), with that of the
internal RAM location indirectly addressed by the specified register. The
high-order nibbles (bits 7-4) of each register are not affected. No flags are
affected.
Example:
R0 contains the address 20H. The accumulator holds the value 36H
(00110110B). Internal RAM location 20H holds the value 75H
(01110101B). The instruction
XCHD
A, @ R0
will leave RAM location 20H holding the value 76H (01110110B) and 35H
(00110101B) in the accumulator.
Operation:
XCHD
(A3-0)
←
→
((Ri)3-0)
Encoding:
1 1 0 1 0 1 1 i
Bytes:
1
Cycles:
1
User’s Manual
4-78
2000-07
C500
Instruction Set
XRL
<dest-byte>, <src-byte>
Function:
Logical Exclusive OR for byte variables
Description:
XRL performs the bitwise logical Exclusive OR operation between the
indicated variables, storing the results in the destination. No flags are
affected (except P, if <dest-byte> = A).
The two operands allow six addressing mode combinations. When the
destination is the accumulator, the source can use register, direct,
register-indirect, or immediate addressing; when the destination is a direct
address, the source can be accumulator or immediate data.
Note:
When this instruction is used to modify an output port, the value used as
the original port data will be read from the output data latch, not the input
pins.
Example:
If the accumulator holds 0C3H (11000011B) and register 0 holds 0AAH
(10101010B) then the instruction
XRL
A,R0
will leave the accumulator holding the value 69H (01101001B).
When the destination is a directly addressed byte, this instruction can
complement combinations of bits in any RAM location or hardware
register. The pattern of bits to be complemented is then determined by a
mask byte, either a constant contained in the instruction or a variable
computed in the accumulator at run-time. The instruction
XRL
P1,#00110001B
will complement bits 5, 4, and 0 of output port 1.
XRL
A,Rn
Operation:
XRL2
(A) ← (A) v (Rn)
Encoding:
0 1 1 0 1 r r r
Bytes:
1
Cycles:
1
User’s Manual
4-79
2000-07
C500
Instruction Set
XRL
A,direct
Operation:
XRL
(A) ← (A) v (direct)
Encoding:
0 1 1 0 0 1 0 1
Bytes:
2
Cycles:
1
XRL
A, @ Ri
Operation:
XRL
(A) ← (A) v ((Ri))
Encoding:
0 1 1 0 0 1 1 i
Bytes:
1
Cycles:
1
XRL
A, #data
Operation:
XRL
(A) ← (A) v #data
Encoding:
0 1 1 0 0 1 0 0
Bytes:
2
Cycles:
1
XRL
direct,A
Operation:
XRL
(direct) ← (direct) v (A)
Encoding:
0 1 1 0 0 0 1 0
Bytes:
2
Cycles:
1
User’s Manual
direct address
immediate data
direct address
4-80
2000-07
C500
Instruction Set
XRL
direct, #data
Operation:
XRL
(direct) ← (direct) v #data
Encoding:
0 1 1 0 0 0 1 1
Bytes:
3
Cycles:
2
User’s Manual
direct address
4-81
immediate data
2000-07
C500
Instruction Set
4.4
Instruction Set Summary Tables
The following two tables give a survey about the instruction set of the C500 family
microcontrollers. In Table 4-3 the instructions are ordered in functional groups. In
Table 4-4 the instructions are ordered in the hexadecimal order of their opcode.
4.4.1
Functional Groups of Instructions
Table 4-3
Instruction Set Summary
Mnemonic
Description
Byte
Cycle
Arithmetic Operations
ADD
A,Rn
Add register to accumulator
1
1
ADD
A,direct
Add direct byte to accumulator
2
1
ADD
A @Ri
Add indirect RAM to accumulator
1
1
ADD
A,#data
Add immediate data to accumulator
2
1
ADDC
A,Rn
Add register to accumulator with carry flag
1
1
ADDC
A,direct
Add direct byte to A with carry flag
2
1
ADDC
A,@Ri
Add indirect RAM to A with carry flag
1
1
ADDC
A, #data
Add immediate data to A with carry flag
2
1
SUBB
A,Rn
Subtract register from A with borrow
1
1
SUBB
A,direct
Subtract direct byte from A with borrow
2
1
SUBB
A,@Ri
Subtract indirect RAM from A with borrow
1
1
SUBB
A,#data
Subtract immediate data from A with borrow
2
1
INC
A
Increment accumulator
1
1
INC
Rn
Increment register
1
1
INC
direct
Increment direct byte
2
1
INC
@Ri
Increment indirect RAM
1
1
DEC
A
Decrement accumulator
1
1
DEC
Rn
Decrement register
1
1
DEC
direct
Decrement direct byte
2
1
DEC
@Ri
Decrement indirect RAM
1
1
INC
DPTR
Increment data pointer
1
2
MUL
AB
Multiply A and B
1
4
DIV
AB
Divide A by B
1
4
DA
A
Decimal adjust accumulator
1
1
User’s Manual
4-82
2000-07
C500
Instruction Set
Table 4-3
Instruction Set Summary (cont’d)
Mnemonic
Description
Byte
Cycle
Logic Operations
ANL
A,Rn
AND register to accumulator
1
1
ANL
A,direct
AND direct byte to accumulator
2
1
ANL
A,@Ri
AND indirect RAM to accumulator
1
1
ANL
A,#data
AND immediate data to accumulator
2
1
ANL
direct,A
AND accumulator to direct byte
2
1
ANL
direct,#data
AND immediate data to direct byte
3
2
ORL
A,Rn
OR register to accumulator
1
1
ORL
A,direct
OR direct byte to accumulator
2
1
ORL
A,@Ri
OR indirect RAM to accumulator
1
1
ORL
A,#data
OR immediate data to accumulator
2
1
ORL
direct,A
OR accumulator to direct byte
2
1
ORL
direct,#data
OR immediate data to direct byte
3
2
XRL
A,Rn
Exclusive OR register to accumulator
1
1
XRL
A direct
Exclusive OR direct byte to accumulator
2
1
XRL
A,@Ri
Exclusive OR indirect RAM to accumulator
1
1
XRL
A,#data
Exclusive OR immediate data to accumulator
2
1
XRL
direct,A
Exclusive OR accumulator to direct byte
2
1
XRL
direct,#data
Exclusive OR immediate data to direct byte
3
2
CLR
A
Clear accumulator
1
1
CPL
A
Complement accumulator
1
1
RL
A
Rotate accumulator left
1
1
RLC
A
Rotate accumulator left through carry
1
1
RR
A
Rotate accumulator right
1
1
RRC
A
Rotate accumulator right through carry
1
1
SWAP
A
Swap nibbles within the accumulator
1
1
Data Transfer1)
MOV
A,Rn
Move register to accumulator
1
1
MOV
A,direct
Move direct byte to accumulator
2
1
MOV
A,@Ri
Move indirect RAM to accumulator
1
1
User’s Manual
4-83
2000-07
C500
Instruction Set
Table 4-3
Instruction Set Summary (cont’d)
Mnemonic
Description
Byte
Cycle
MOV
A,#data
Move immediate data to accumulator
2
1
MOV
Rn,A
Move accumulator to register
1
1
MOV
Rn,direct
Move direct byte to register
2
2
MOV
Rn,#data
Move immediate data to register
2
1
MOV
direct,A
Move accumulator to direct byte
2
1
MOV
direct,Rn
Move register to direct byte
2
2
MOV
direct,direct
Move direct byte to direct byte
3
2
MOV
direct,@Ri
Move indirect RAM to direct byte
2
2
MOV
direct,#data
Move immediate data to direct byte
3
2
MOV
@Ri,A
Move accumulator to indirect RAM
1
1
MOV
@Ri,direct
Move direct byte to indirect RAM
2
2
MOV
@Ri, #data
Move immediate data to indirect RAM
2
1
MOV
DPTR, #data16
Load data pointer with a 16-bit constant
3
2
MOVC
A,@A + DPTR
Move code byte relative to DPTR to accumulator
1
2
MOVC
A,@A + PC
Move code byte relative to PC to accumulator
1
2
MOVX
A,@Ri
Move external RAM (8-bit addr.) to A
1
2
MOVX
A,@DPTR
Move external RAM (16-bit addr.) to A
1
2
MOVX
@Ri,A
Move A to external RAM (8-bit addr.)
1
2
MOVX
@DPTR,A
Move A to external RAM (16-bit addr.)
1
2
PUSH
direct
Push direct byte onto stack
2
2
POP
direct
Pop direct byte from stack
2
2
XCH
A,Rn
Exchange register with accumulator
1
1
XCH
A,direct
Exchange direct byte with accumulator
2
1
XCH
A,@Ri
Exchange indirect RAM with accumulator
1
1
XCHD
A,@Ri
Exchange low-order nibble indir. RAM with A
1
1
Boolean Variable Manipulation
CLR
C
Clear carry flag
1
1
CLR
bit
Clear direct bit
2
1
SETB
C
Set carry flag
1
1
SETB
bit
Set direct bit
2
1
CPL
C
Complement carry flag
1
1
CPL
bit
Complement direct bit
2
1
User’s Manual
4-84
2000-07
C500
Instruction Set
Table 4-3
Instruction Set Summary (cont’d)
Mnemonic
Description
Byte
Cycle
ANL
C,bit
AND direct bit to carry flag
2
2
ANL
C,/bit
AND complement of direct bit to carry
2
2
ORL
C,bit
OR direct bit to carry flag
2
2
ORL
C,/bit
OR complement of direct bit to carry
2
2
MOV
C,bit
Move direct bit to carry flag
2
1
MOV
bit,C
Move carry flag to direct bit
2
2
Program and Machine Control
ACALL
addr11
Absolute subroutine call
2
2
LCALL
addr16
Long subroutine call
3
2
RET
Return from subroutine
1
2
RETI
Return from interrupt
1
2
AJMP
addr11
Absolute jump
2
2
LJMP
addr16
Long iump
3
2
SJMP
rel
Short jump (relative addr.)
2
2
JMP
@A + DPTR
Jump indirect relative to the DPTR
1
2
JZ
rel
Jump if accumulator is zero
2
2
JNZ
rel
Jump if accumulator is not zero
2
2
JC
rel
Jump if carry flag is set
2
2
JNC
rel
Jump if carry flag is not set
2
2
JB
bit,rel
Jump if direct bit is set
3
2
JNB
bit,rel
Jump if direct bit is not set
3
2
JBC
bit,rel
Jump if direct bit is set and clear bit
3
2
CJNE
A,direct,rel
Compare direct byte to A and jump if not equal
3
2
CJNE
A,#data,rel
Compare immediate to A and jump if not equal
3
2
CJNE
Rn,#data rel
Compare immed. to reg. and jump if not equal
3
2
CJNE
@Ri,#data,rel
Compare immed. to ind. and jump if not equal
3
2
DJNZ
Rn,rel
Decrement register and jump if not zero
2
2
DJNZ
direct,rel
Decrement direct byte and jump if not zero
3
2
No operation
1
1
NOP
1)
MOV A,ACC is not a valid instruction.
User’s Manual
4-85
2000-07
C500
Instruction Set
4.4.2
Hexadecimal Ordered Instructions
Table 4-4
Instruction List in Hexadecimal Order
OpCode
Mnemonic
OpCode
Mnemonic
OpMnemonic
Code
00H
NOP
20H
JB
bit.rel
40H
JC
rel
01H
AJMP
addr11
21H
AJMP
addr11
41H
AJMP
addr11
02H
LJMP
addr16
22H
RET
42H
ORL
direct,A
03H
RR
A
23H
RL
A
43H
ORL
direct,#data
04H
INC
A
24H
ADD
A,#data
44H
ORL
A,#data
05H
INC
direct
25H
ADD
A,direct
45H
ORL
A,direct
06H
INC
@R0
26H
ADD
A,@R0
46H
ORL
A,@R0
07H
INC
@R1
27H
ADD
A,@R1
47H
ORL
A,@R1
08H
INC
R0
28H
ADD
A,R0
48H
ORL
A,R0
09H
INC
R1
29H
ADD
A,R1
49H
ORL
A,R1
0AH
INC
R2
2AH
ADD
A,R2
4AH
ORL
A,R2
0BH
INC
R3
2BH
ADD
A,R3
4BH
ORL
A,R3
0CH
INC
R4
2CH
ADD
A,R4
4CH
ORL
A,R4
0DH
INC
R5
2DH
ADD
A,R5
4DH
ORL
A,R5
0EH
INC
R6
2EH
ADD
A,R6
4EH
ORL
A,R6
0FH
INC
R7
2FH
ADD
A,R7
4FH
ORL
A,R7
10H
JBC
bit,rel
30H
JNB
bit.rel
50H
JNC
rel
11H
ACALL
addr11
31H
ACALL
addr11
51H
ACALL
addr11
12H
LCALL
addr16
32H
RETI
52H
ANL
direct,A
13H
RRC
A
33H
RLC
A
53H
ANL
direct,#data
14H
DEC
A
34H
ADDC
A,#data
54H
ANL
A,#data
15H
DEC
direct
35H
ADDC
A,direct
55H
ANL
A,direct
16H
DEC
@R0
36H
ADDC
A,@R0
56H
ANL
A,@R0
17H
DEC
@R1
37H
ADDC
A,@R1
57H
ANL
A,@R1
18H
DEC
R0
38H
ADDC
A,R0
58H
ANL
A,R0
19H
DEC
R1
39H
ADDC
A,R1
59H
ANL
A,R1
1AH
DEC
R2
3AH
ADDC
A,R2
5AH
ANL
A,R2
1BH
DEC
R3
3BH
ADDC
A,R3
5BH
ANL
A,R3
1CH
DEC
R4
3CH
ADDC
A,R4
5CH
ANL
A,R4
1DH
DEC
R5
3DH
ADDC
A,R5
5DH
ANL
A,R5
1EH
DEC
R6
3EH
ADDC
A,R6
5EH
ANL
A,R6
1FH
DEC
R7
3FH
ADDC
A,R7
5FH
ANL
A,R7
User’s Manual
4-86
2000-07
C500
Instruction Set
Table 4-4
Instruction List in Hexadecimal Order (cont’d)
OpCode
Mnemonic
OpCode
Mnemonic
OpMnemonic
Code
60H
JZ
rel
80H
SJMP
rel
A0H
ORL
C,/bit
61H
AJMP
addr11
81H
AJMP
addr11
A1H
AJMP
addr11
62H
XRL
direct,A
82H
ANL
C,bit
A2H
MOV
C,bit
63H
XRL
direct,#data 83H
MOVC
A,@A+PC
A3H
INC
DPTR
64H
XRL
A,#data
84H
DIV
AB
A4H
MUL
AB
65H
XRL
A,direct
85H
MOV
direct,direct
A5H
-
66H
XRL
A,@R0
86H
MOV
direct,@R0
A6H
MOV
@R0,direct
67H
XRL
A,@R1
87H
MOV
direct,@R1
A7H
MOV
@R1,direct
68H
XRL
A,R0
88H
MOV
direct,R0
A8H
MOV
R0,direct
69H
XRL
A,R1
89H
MOV
direct,R1
A9H
MOV
R1,direct
6AH
XRL
A,R2
8AH
MOV
direct,R2
AAH
MOV
R2,direct
6BH
XRL
A,R3
8BH
MOV
direct,R3
ABH
MOV
R3,direct
6CH
XRL
A,R4
8CH
MOV
direct,R4
ACH
MOV
R4,direct
6DH
XRL
A,R5
8DH
MOV
direct,R5
ADH
MOV
R5,direct
6EH
XRL
A,R6
8EH
MOV
direct,R6
AEH
MOV
R6,direct
6FH
XRL
A,R7
8FH
MOV
direct,R7
AFH
MOV
R7,direct
70H
JNZ
rel
90H
MOV
DPTR,#data16 B0H
ANL
C,/bit
71H
ACALL
addr11
91H
ACALL
addr11
B1H
ACALL
addr11
72H
ORL
C,direct
92H
MOV
bit,C
B2H
CPL
bit
73H
JMP
@A+DPTR 93H
MOVC
A,@A+DPTR
B3H
CPL
C
74H
MOV
A,#data
94H
SUBB
A,#data
B4H
CJNE
A,#data,rel
75H
MOV
direct,#data 95H
SUBB
A,direct
B5H
CJNE
A,direct,rel
76H
MOV
@R0,#data 96H
SUBB
A,@R0
B6H
CJNE
@R0,#data,rel
77H
MOV
@R1,#data 97H
SUBB
A,@R1
B7H
CJNE
@R1,#data,rel
78H
MOV
R0.#data
98H
SUBB
A,R0
B8H
CJNE
R0,#data,rel
79H
MOV
R1.#data
99H
SUBB
A,R1
B9H
CJNE
R1,#data,rel
7AH
MOV
R2.#data
9AH
SUBB
A,R2
BAH
CJNE
R2,#data,rel
7BH
MOV
R3.#data
9BH
SUBB
A,R3
BBH
CJNE
R3,#data,rel
7CH
MOV
R4.#data
9CH
SUBB
A,R4
BCH
CJNE
R4,#data,rel
7DH
MOV
R5.#data
9DH
SUBB
A,R5
BDH
CJNE
R5,#data,rel
7EH
MOV
R6.#data
9EH
SUBB
A,R6
BEH
CJNE
R6,#data,rel
7FH
MOV
R7.#data
9FH
SUBB
A,R7
BFH
CJNE
R7,#data,rel
User’s Manual
4-87
2000-07
C500
Instruction Set
Table 4-4
Instruction List in Hexadecimal Order (cont’d)
OpCode
Mnemonic
OpCode
Mnemonic
C0H
PUSH
direct
E0H
MOVX
A,@DPTR
C1H
AJMP
addr11
E1H
AJMP
addr11
C2H
CLR
bit
E2H
MOVX
A,@R0
C3H
CLR
C
E3H
MOVX
A,@R1
C4H
SWAP
A
E4H
CLR
A
C5H
XCH
A,direct
E5H
MOV
A,direct
C6H
XCH
A,@R0
E6H
MOV
A,@R0
C7H
XCH
A,@R1
E7H
MOV
A,@R1
C8H
XCH
A,R0
E8H
MOV
A,R0
C9H
XCH
A,R1
E9H
MOV
A,R1
CAH
XCH
A,R2
EAH
MOV
A,R2
CBH
XCH
A,R3
EBH
MOV
A,R3
CCH
XCH
A,R4
ECH
MOV
A,R4
CDH
XCH
A,R5
EDH
MOV
A,R5
CEH
XCH
A,R6
EEH
MOV
A,R6
CFH
XCH
A,R7
EFH
MOV
A,R7
D0H
POP
direct
F0H
MOVX
@DPTR,A
D1H
ACALL
addr11
F1H
ACALL
addr11
D2H
SETB
bit
F2H
MOVX
@R0,A
D3H
SETB
C
F3H
MOVX
@R1,A
D4H
DA
A
F4H
CPL
A
D5H
DJNZ
direct,rel
F5H
MOV
direct,A
D6H
XCHD
A,@R0
F6H
MOV
@R0,A
D7H
XCHD
A,@R1
F7H
MOV
@R1,A
D8H
DJNZ
R0,rel
F8H
MOV
R0,A
D9H
DJNZ
R1,rel
F9H
MOV
R1,A
DAH
DJNZ
R2,rel
FAH
MOV
R2,A
DBH
DJNZ
R3,rel
FBH
MOV
R3,A
DCH
DJNZ
R4,rel
FCH
MOV
R4,A
DDH
DJNZ
R5,rel
FDH
MOV
R5,A
DEH
DJNZ
R6,rel
FEH
MOV
R6,A
DFH
DJNZ
R7,rel
FFH
MOV
R7,A
User’s Manual
4-88
OpMnemonic
Code
2000-07
Infineon goes for Business Excellence
“Business excellence means intelligent approaches and clearly
defined processes, which are both constantly under review and
ultimately lead to good operating results.
Better operating results and business excellence mean less
idleness and wastefulness for all of us, more professional
success, more accurate information, a better overview and,
thereby, less frustration and more satisfaction.”
Dr. Ulrich Schumacher
http://www.infineon.com
Published by Infineon Technologies AG