ST72C254G2M6 STMicroelectronics, ST72C254G2M6 Datasheet - Page 90

• Manufacturer Part Number: ST72C254G2M6
• Description: IC MCU 8BIT 8K FLASH SOIC-28
• Manufacturer: STMicroelectronics
• Series: ST7r

Specifications of ST72C254G2M6

• Core Processor: ST7
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 3.2 V ~ 5.5 V
• Data Converters: A/D 6x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 28-SOIC (7.5mm Width)
• Controller Family/series: ST7
• No. Of I/o's: 22
• Ram Memory Size: 256Byte
• Cpu Speed: 8MHz
• No. Of Timers: 2
• Rohs Compliant: Yes
• Processor Series: ST72C2x
• Core: ST7
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: I2C, SPI
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 22
• Number Of Timers: 3 bit
• Operating Supply Voltage: 3.2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: ST7MDT1-DVP2/US
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: In Transition

ST72104Gx, ST72215Gx, ST72216Gx, ST72254Gx
12 INSTRUCTION SET
12.1 ST7 ADDRESSING MODES
The ST7 Core features 17 different addressing
modes which can be classified in 7 main groups:
The ST7 Instruction set is designed to minimize
the number of bytes required per instruction: To do
Table 19. ST7 Addressing Mode Overview
Note 1. At the time the instruction is executed, the Program Counter (PC) points to the instruction follow-
ing JRxx.
90/141
Addressing Mode
Inherent
Immediate
Direct
Indexed
Indirect
Relative
Bit operation
Inherent
Immediate
Short
Long
No Offset
Short
Long
Short
Long
Short
Long
Relative
Relative
Bit
Bit
Bit
Bit
Mode
Direct
Direct
Direct
Direct
Direct
Indirect
Indirect
Indirect
Indirect
Direct
Indirect
Direct
Indirect
Direct
Indirect
Indexed
Indexed
Indexed
Indexed
Indexed
Relative
Relative
Example
nop
ld A,#$55
ld A,$55
ld A,($55,X)
ld A,([$55],X)
jrne loop
bset
byte,#5
nop
ld A,#$55
ld A,$10
ld A,$1000
ld A,(X)
ld A,($10,X)
ld A,($1000,X)
ld A,[$10]
ld A,[$10.w]
ld A,([$10],X)
ld A,([$10.w],X)
jrne loop
jrne [$10]
bset $10,#7
bset [$10],#7
btjt $10,#7,skip
btjt [$10],#7,skip 00..FF
Syntax
00..FF
0000..FFFF
00..FF
00..1FE
0000..FFFF
00..FF
0000..FFFF
00..1FE
0000..FFFF
PC-128/PC+127
PC-128/PC+127
00..FF
00..FF
00..FF
Destination/
so, most of the addressing modes may be subdi-
vided in two sub-modes called long and short:
– Long addressing mode is more powerful be-
– Short addressing mode is less powerful because
The ST7 Assembler optimizes the use of long and
short addressing modes.
Source
cause it can use the full 64 Kbyte address space,
however it uses more bytes and more CPU cy-
cles.
it can generally only access page zero (0000h -
00FFh range), but the instruction size is more
compact, and faster. All memory to memory in-
structions use short addressing modes only
(CLR, CPL, NEG, BSET, BRES, BTJT, BTJF,
INC, DEC, RLC, RRC, SLL, SRL, SRA, SWAP)
1)
1)
00..FF
00..FF
00..FF
00..FF
00..FF
00..FF
00..FF
Address
Pointer
(Hex.)
byte
word
byte
word
byte
byte
byte
Pointer
(Hex.)
Size
+ 0
+ 1
+ 1
+ 2
+ 0 (with X register)
+ 1 (with Y register)
+ 1
+ 2
+ 2
+ 2
+ 2
+ 2
+ 1
+ 2
+ 1
+ 2
+ 2
+ 3
(Bytes)
Length