SYNCMOS SM8952BW40PP

FOSVOS TEL: 021-58998693
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Product List ................................................................................................................................................................... 2
Description .................................................................................................................................................................... 2
Ordering Information ..................................................................................................................................................... 2
Features ........................................................................................................................................................................ 2
Pin Configuration .......................................................................................................................................................... 3
Block Diagram............................................................................................................................................................... 6
Special Function Register (SFR) .................................................................................................................................. 8
Function Description ................................................................................................................................................... 10
1.
General Features ........................................................................................................................................... 10
1.1
Embedded Flash ................................................................................................................................... 10
1.2
IO Pads ................................................................................................................................................. 10
1.3
System Control Register (SCONF) ....................................................................................................... 10
2.
Instruction Set ................................................................................................................................................ 11
3.
Memory Structure .......................................................................................................................................... 15
3.1
Program Memory .................................................................................................................................. 15
3.2
Data Memory......................................................................................................................................... 16
3.3
Data memory - lower 128 byte (00h to 7Fh) ......................................................................................... 16
3.4
Data memory - higher 128 byte (80h to FFh)........................................................................................ 16
4.
CPU Engine ................................................................................................................................................... 17
4.1
Accumulator .......................................................................................................................................... 17
4.2
B Register ............................................................................................................................................. 17
4.3
Program Status Word ............................................................................................................................ 18
4.4
Stack Pointer ......................................................................................................................................... 18
4.5
Data Pointer .......................................................................................................................................... 18
5.
GPIO .............................................................................................................................................................. 19
6.
Timer 0 and Timer 1 ....................................................................................................................................... 20
6.1
Timer/counter mode control register (TMOD) ....................................................................................... 20
6.2
Timer/counter control register (TCON) ................................................................................................. 21
6.3
Mode 0 (13-bit Counter/Timer) .............................................................................................................. 21
6.4
Mode 1 (16-bit Counter/Timer) .............................................................................................................. 22
6.5
Mode 2 (8-bit auto-reload Counter/Timer) ............................................................................................ 22
6.6
Mode 3 (Timer 0 acts as two independent 8 bit Timers / Counters) .....................................................22
7.
Timer 2 ........................................................................................................................................................... 24
7.1
Capture mode ....................................................................................................................................... 25
7.2
Auto-reload (Up or Down Counter) ....................................................................................................... 26
7.3
Programmable clock out ....................................................................................................................... 27
8.
Serial interface – UART ................................................................................................................................. 29
8.1
Serial interface ...................................................................................................................................... 29
8.1.1
Mode 0.......................................................................................................................................... 30
8.1.2
Mode 1.......................................................................................................................................... 30
8.1.3
Mode 2.......................................................................................................................................... 31
8.1.4
Mode 3.......................................................................................................................................... 31
8.2
Multiprocessor Communication of Serial Interface ............................................................................... 31
8.3
Baud Rate Generator ............................................................................................................................ 32
8.3.1
Serial interface Mode 0 ................................................................................................................ 32
8.3.2
Serial interface Mode 2 ................................................................................................................ 32
8.3.3
Serial interface Mode 1 and 3 ...................................................................................................... 32
9.
Interrupt.......................................................................................................................................................... 33
10.
Watch Dog Timer ........................................................................................................................................... 35
11.
Power Management Unit ............................................................................................................................... 37
11.1
Idle mode .............................................................................................................................................. 37
11.2
Power Down mode ................................................................................................................................ 37
Operating Conditions .................................................................................................................................................. 38
DC Characteristics ...................................................................................................................................................... 38
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-1-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Product List
Features
Description

SM8952BW40PP,
SM8952BW44JP,
SM8952BW44QP,
The SM8952B series product is an 8 - bit single chip
micro controller with 8KB flash & 256 bytes SRAM
embedded. It is a derivative of the 8052 microcontroller
family.
SM8952B is a versatile and cost effective controller for
those applications which demand up to 32 I/O pins, or
applications which need up to 8K byte flash memory
either for program or for data or mixed.
To program the on-chip flash memory, a commercial
writer is available to do it in parallel programming
method.
Ordering Information
SM8952BihhkL yymmv
i: process identifier { W = 2.4V ~ 5.5V}
hh: pin count
k: package type postfix {as table below }
L:PB Free identifier
{No text is Non-PB free，”P” is PB free}
yy: year
mm: month
v: version identifier{ A, B,…}
Postfix
Package
P
PDIP
J
PLCC
Q
PQFP














Main Flash ROM 8KB
Working voltage 2.4V~5.5V
4.5V ~ 5.5V runs up to 40MHz
2.4V ~ 3.6V runs up to 24MHz
General 8052 family compatible with 12
clocks in one machine cycle
6 clocks in one machine cycle is also
supported
256 bytes SRAM as standard 8052.
16-bit Data Pointers (DPTR).
One serial peripheral interfaces in full duplex
mode (UART).
-
Synchronous mode, fixed baud rate.
8-bit UART mode, variable baud rate.
9-bit UART mode, fixed baud rate.
9-bit UART mode, variable baud rate.
Three 16-bit Timer/Counters. (Timer 0, 1, 2).
One watch dog timer (WDT).
Six interrupt sources with two priority levels.
Four 8-bit I/O ports
IO PAD ESD over 4KV
Enhance user code protection.
Power management unit for IDLE and power
down modes.
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-2-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Pin Configuration
40 Pin PDIP
1
40
VDD
T2EX/P1.1
2
39
P0.0/AD0
P1.2
3
38
P0.1/AD1
P1.3
4
37
P0.2/AD2
P1.4
5
36
P0.3/AD3
P1.5
6
35
P0.4/AD4
P1.6
7
34
P0.5/AD5
P1.7
8
33
P0.6/AD6
RESET
9
32
P0.7/AD7
31
EA
30
ALE
29
PSEN
28
P2.7/A15
27
P2.6/A14
T1/P3.5 15
26
P2.5/A13
WR/P3.6 16
25
P2.4/A12
RD/P3.7 17
24
P2.3/A11
XTAL2 18
23
P2.2/A10
XTAL1 19
22
P2.1/A9
VSS 20
21
P2.0/A8
RXD/P3.0 10
TXD/P3.1 11
INT0/P3.2 12
INT1/P3.3 13
T0/P3.4 14
SM8952BihhPP
yymmv
(40L PDIP Top View)
T2/P1.0
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-3-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
P1.2
P1.1/T2EX
P1.0/T2
NC
VDD
P0.0/AD0
P0.1/AD1
P0.2/AD2
P0.3/AD3
8
18
19
20
21
22
23
24
25
26
27
28
A11/P2.3
A12/P2.4
SM8952B
ihhJP
yymmv
(44L PLCC Top View)
29 30 31 32 33 34 35 36 37 38 39
P1.3
40
7
41
A10/P2.2
T1/P3.5
42
A9/P2.1
T0/P3.4
43
A8/P2.0
INT1/P3.3
44
NC
INT0/P3.2
1
VSS
TXD/P3.1
2
XTAL1
NC
3
XTAL2
RXD/P3.0
4
RD/P3.7
RESET
5
WR/P3.6
P1.7
6
9
P1.6
17 16 15 14 13 12 11 10
P1.5
P1.4
44 Pin PLCC
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
EA
NC
ALE
PSEN
P2.7/A15
P2.6/A14
P2.5/A13
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-4-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
P0.4/AD4
P0.5/AD5
P0.6/AD6
P0.7/AD7
EA
NC
ALE
PSEN
P2.7/A15
P2.6/A14
P2.5/A13
33
32
31
30
29
28
27
26
25
24
23
44 Pin PQFP
AD3/P0.3 34
22
P2.4/A12
AD2/P0.2 35
21
P2.3/A11
AD1/P0.1 36
20
P2.2/A10
AD0/P0.0 37
19
P2.1/A9
18
P2.0/A8
17
NC
16
VSS
15
XTAL1
14
XTAL2
13
P3.7/RD
12
P3.6/WR
6
7
8
9
NC
TXD/P3.1
INT0/P3.2
INT1/P3.3
T1/P3.5 11
5
RXD/P3.0
T0/P3.4 10
4
RESET
P1.4 44
(44L PQFP Top View)
3
P1.3 43
P1.7
P1.2
42
2
T2EX/P1.1 41
P1.6
T2/P1.0 40
1
NC 39
SM8952B
ihhQP
yymmv
P1.5
VDD 38
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-5-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
RESET
Reset Circuit
TXD
RXD
Block Diagram
UART
SRAM
256Bytes
XTAL2
XTAL1
EA
PSEN
ALE
Flash 8KBytes
CPU
Port 0
Port 0
Port 1
Port 1
Port 2
Port 2
Port 3
Port 3
Timer 0/1
T0
T1
WDT
Interrupt
Timer2
T2
T2EX
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Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-6-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Pin Description
40L
PDIP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
40L
PLCC
2
3
4
5
6
7
8
9
10
11
13
14
15
16
17
18
19
20
21
22
24
25
26
27
28
29
30
31
32
33
35
36
37
38
39
40
41
42
43
44
40L
PQFP
40
41
42
43
44
1
2
3
4
5
7
8
9
10
11
12
13
14
15
16
18
19
20
21
22
23
24
25
26
27
29
30
31
32
33
34
35
36
37
38
Symbol
P1.0/T2
P1.1/T2EX
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
RESET
P3.0/RXD
P3.1/TXD
P3.2/INT0
P3.3/INT1
P3.4/T0
P3.5/T1
P3.6/WR
P3.7/RD
XTAL2
XTAL1
VSS
P2.0/A8
P2.1/A9
P2.2/A10
P2.3/A11
P2.4/A12
P2.5/A13
P2.6/A14
P2.7/A15
PSEN
ALE
EA
P0.7/AD7
P0.6/AD6
P0.5/AD5
P0.4/AD4
P0.3/AD3
P0.2/AD2
P0.1/AD1
P0.0/AD0
VDD
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
O
O
I
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I/O
I
Description
Bit 0 of port 1 & Timer 2 external input clock
Bit 1 of port 1 & Timer 2 capture trigger
Bit 2 of port 1
Bit 3 of port 1
Bit 4 of port 1
Bit 5 of port 1
Bit 6 of port 1
Bit 7 of port 1
Reset pin
Bit 0 of port 3 & Serial interface channel receive data
Bit 1 of port 3 & Serial interface channel Transmit data
Bit 2 of port 3 & Interrupt 0
Bit 3 of port 3 & Interrupt 1
Bit 4 of port 3 & Timer 0 external input
Bit 5 of port 3 & Timer 1 external input
Bit 6 of port 3 & external memory write
Bit 7 of port 3 & external memory read
Crystal output
Crystal input
Ground
Bit 0 of port 2 & bit 8 of external memory address
Bit 1 of port 2 & bit 9 of external memory address
Bit 2 of port 2 & bit 10 of external memory address
Bit 3 of port 2 & bit 11 of external memory address
Bit 4 of port 2 & bit 12 of external memory address
Bit 5 of port 2 & bit 13 of external memory address
Bit 6 of port 2 & bit 14 of external memory address
Bit 7 of port 2 & bit 15 of external memory address
program storage enable
address latch enable
external access
Bit 7 of port 0 & data/address bit 7 of external memory
Bit 6 of port 0 & data/address bit 6 of external memory
Bit 5 of port 0 & data/address bit 5 of external memory
Bit 4 of port 0 & data/address bit 4 of external memory
Bit 3 of port 0 & data/address bit 3 of external memory
Bit 2 of port 0 & data/address bit 2 of external memory
Bit 1 of port 0 & data/address bit 1 of external memory
Bit 0 of port 0 & data/address bit 0 of external memory
Power supply
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-7-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Special Function Register (SFR)
A map of the Special Function Registers is shown as below:
Hex\Bin
X000
X001
X010
X011
X100
X101
X110
X111
F8
Bin/Hex
FF
F0
B
F7
E8
E0
ACC
EF
E7
D8
DF
D0
PSW
D7
C8
C0
T2CON
B8
IP
B0
P3
B7
A8
A0
IE
P2
AF
A7
98
SCON
90
P1
88
80
Hex\Bin
TCON
P0
X000
T2MOD
RCAP2L
RCAP2H
TL2
CF
C7
TH2
SCONF
SBUF
WDTC
BF
9F
97
TMOD
SP
X001
TL0
DPL
X010
TL1
DPH
X011
TH0
X100
TH1
X101
X110
PCON
X111
8F
87
Bin/Hex
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-8-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Note: Special Function Registers reset values and description for SM8952B.
Register
Location
Reset value
1
2
P0
SP
80H
81H
FFH
07H
Port 0
Stack Pointer
3
DPL
DPH
PCON
TCON
TMOD
82H
83H
87H
88H
89H
00H
00H
00H
00H
00H
Data Pointer 0 low byte
Data Pointer 0 high byte
Power Control
Timer/Counter Control
Timer Mode Control
9
10
11
12
TL0
TL1
TH0
TH1
P1
8AH
8BH
8CH
8DH
90H
00H
00H
00H
00H
FFH
Timer 0, low byte
Timer 1, low byte
Timer 0, high byte
Timer 1, high byte
Port 1
13
SCON
98H
00H
Serial Port 0, Control Register
14
SBUF
99H
00H
Serial Port 0, Data Buffer
16
P2
A0H
FFH
Port 2
17
IE
A8H
00H
Interrupt Enable
18
P3
B0H
FFH
Port 3
19
IP
B8H
00H
Interrupt Priority
20
SCONF
BFH
02H
System Control Register
21
T2CON
C8H
00H
Timer 2 Control
4
5
6
7
8
Description
22
T2MOD
C9H
00H
Timer 2 Mode
23
RCAP2L
CAH
00H
Timer2 Capture Low
24
RCAP2H
CBH
00H
Timer2 Capture High
25
00H
Timer 2, low byte
TL2
CCH
26
TH2
CDH
00H
Timer 2, high byte
27
PSW
D0H
00H
Program Status Word
28
ACC
E0H
00H
Accumulator
29
B
F0H
00H
B Register
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Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
-9-
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Function Description
1.
General Features
SM8952B is an 8-bit micro-controller. All of its functions and the detailed meanings of SFR will be given in the
following sections.
1.1
Embedded Flash
The program can be loaded into the embedded 8KB Flash memory via its writer.
1.2
IO Pads
The SM8952B has Five I/O ports: Port 0, Port 1, Port 2, Port 3. Port 0~Port 3 are 8-bit ports. These are: quasibidirectional (standard 8051 port outputs) with Port 1~3, and open drain with Port 0.
All the pads are with slew rate to reduce EMI. The IO pads can withstand ESD in human body mode guaranteeing
the SM8952B’s quality in high electro-static environments.
1.3
System Control Register (SCONF)
Mnemonic: SCONF
7
6
WDR
-
5
-
4
-
3
-
2
-
Address: BFh
0
Reset
ALEI
00H
1
-
WDR Watch Dog Timer Reset.
When system reset by Watch Dog Timer overflow, WDR will be set to 1.
User should check WDR bit whenever un-predicted reset happened.
ALEI ALE output inhibit bit.
When default, It can inhibit the clock signal in (Fosc/6) Hz output to the ALE pin.
When set to 1, the ALE pin output will stop to reduce EMI.
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 10 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
2. Instruction Set
All SM8952B instructions are binary code compatible and perform the same functions as they do with the industry
standard 8051. The following tables give a summary of the instruction set cycles of the SM8952B Microcontroller
core. As given in Table
Mnemonic
ADD A,Rn
Table 2-1: Arithmetic operations
Description
Add register to accumulator
Code
28-2F
Bytes
1
Cycles
1
ADD A,direct
Add direct byte to accumulator
25
2
1
ADD A,@Ri
Add indirect RAM to accumulator
26-27
1
1
ADD A,#data
ADDC A,Rn
Add immediate data to accumulator
Add register to accumulator with carry flag
24
38-3F
2
1
1
1
ADDC A,direct
Add direct byte to A with carry flag
35
2
1
ADDC A,@Ri
Add indirect RAM to A with carry flag
36-37
1
1
ADDC A,#data
SUBB A,Rn
Add immediate data to A with carry flag
Subtract register from A with borrow
34
98-9F
2
1
1
1
SUBB A,direct
Subtract direct byte from A with borrow
95
2
1
SUBB A,@Ri
Subtract indirect RAM from A with borrow
96-97
1
1
SUBB A,#data
INC A
INC Rn
Subtract immediate data from A with borrow
Increment accumulator
Increment register
94
04
08-0F
2
1
1
1
1
1
INC direct
Increment direct byte
05
2
1
INC @Ri
Increment indirect RAM
06-07
1
1
INC DPTR
DEC A
Increment data pointer
Decrement accumulator
A3
14
1
1
2
1
DEC Rn
Decrement register
18-1F
1
1
DEC direct
Decrement direct byte
15
2
1
DEC @Ri
MUL AB
Decrement indirect RAM
Multiply A and B
16-17
A4
1
1
1
4
DIV
Divide A by B
84
1
4
DA A
Decimal adjust accumulator
D4
1
1
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 11 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Table 2-2: Logic operations
Description
AND register to accumulator
Code
58-5F
ANL A,direct
AND direct byte to accumulator
ANL A,@Ri
AND indirect RAM to accumulator
ANL A,#data
ANL direct,A
Mnemonic
ANL A,Rn
Bytes
1
Cycles
1
55
2
1
56-57
1
1
AND immediate data to accumulator
AND accumulator to direct byte
54
52
2
2
1
1
ANL direct,#data
AND immediate data to direct byte
53
3
2
ORL A,Rn
OR register to accumulator
48-4F
1
1
ORL A,direct
ORL A,@Ri
OR direct byte to accumulator
OR indirect RAM to accumulator
45
46-47
2
1
1
1
ORL A,#data
OR immediate data to accumulator
44
2
1
ORL direct,A
OR accumulator to direct byte
42
2
1
ORL direct,#data
XRL A,Rn
OR immediate data to direct byte
Exclusive OR register to accumulator
43
68-6F
3
1
2
1
XRL A,direct
Exclusive OR direct byte to accumulator
65
2
1
XRL A,@Ri
Exclusive OR indirect RAM to accumulator
66-67
1
1
XRL A,#data
Exclusive OR immediate data to accumulator
64
2
1
XRL direct,A
XRL direct,#data
Exclusive OR accumulator to direct byte
Exclusive OR immediate data to direct byte
62
63
2
3
1
2
CLR A
Clear accumulator
E4
1
1
CPL A
Complement accumulator
F4
1
1
RL A
RLC A
Rotate accumulator left
Rotate accumulator left through carry
23
33
1
1
1
1
RR A
Rotate accumulator right
03
1
1
RRC A
Rotate accumulator right through carry
13
1
1
SWAP A
Swap nibbles within the accumulator
C4
1
1
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 12 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Mnemonic
MOV A,Rn
MOV A,direct
Table 2-3: Data transfer
Description
Move register to accumulator
Move direct byte to accumulator
Code
E8-EF
E5
Bytes
1
2
Cycles
1
1
MOV A,@Ri
MOV A,#data
MOV Rn,A
MOV Rn,direct
Move indirect RAM to accumulator
Move immediate data to accumulator
Move accumulator to register
Move direct byte to register
E6-E7
74
F8-FF
A8-AF
1
2
1
2
1
MOV Rn,#data
MOV direct,A
MOV direct,Rn
MOV direct1,direct2
Move immediate data to register
Move accumulator to direct byte
Move register to direct byte
Move direct byte to direct byte
78-7F
F5
88-8F
85
2
2
2
3
MOV direct,@Ri
MOV direct,#data
MOV @Ri,A
MOV @Ri,direct
Move indirect RAM to direct byte
Move immediate data to direct byte
Move accumulator to indirect RAM
Move direct byte to indirect RAM
86-87
75
F6-F7
A6-A7
2
3
1
2
MOV @Ri,#data
Move immediate data to indirect RAM
76-77
2
1
3
2
MOV DPTR,#data16
Load data pointer with a 16-bit constant
90
1
1
2
1
1
2
2
2
2
1
2
MOVX A,@Ri
Move external RAM (8-bit addr.) to A
E2-E3
1
2
MOVX A,@DPTR
MOVX @Ri,A
MOVX @DPTR,A
Move external RAM (16-bit addr.) to A
Move A to external RAM (8-bit addr.)
Move A to external RAM (16-bit addr.)
E0
F2-F3
F0
1
1
1
MOVC A,@A+DPTR
Move code byte relative to DPTR to accumulator
93
1
2
2
2
2
MOVC A,@A+PC
PUSH direct
Move code byte relative to PC to accumulator
Push direct byte onto stack
83
C0
1
2
2
2
POP direct
XCH A,Rn
XCH A,direct
XCH A,@Ri
XCHD A,@Ri
Pop direct byte from stack
Exchange register with accumulator
Exchange direct byte with accumulator
Exchange indirect RAM with accumulator
Exchange low-order nibble indir. RAM with A
D0
C8-CF
C5
C6-C7
D6-D7
2
1
2
1
1
2
1
1
1
1
FOSVOS TEL: 021-58998693
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 13 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Table 2-4: Program branches
Description
Absolute subroutine call
Code
xxx11
LCALL addr16
Long subroutine call
12
3
Cycles
2
2
RET
from subroutine
22
1
2
RETI
AJMP addr11
from interrupt
Absolute jump
32
xxx01
1
2
LJMP addr16
Long iump
02
3
2
2
2
SJMP rel
Short jump (relative addr.)
80
2
2
JMP @A+DPTR
JZ rel
Jump indirect relative to the DPTR
Jump if accumulator is zero
73
60
1
2
Mnemonic
ACALL addr11
Bytes
2
JNZ rel
Jump if accumulator is not zero
70
2
2
2
2
JC rel
Jump if carry flag is set
40
2
2
JNC
JB bit,rel
Jump if carry flag is not set
Jump if direct bit is set
50
20
2
3
JNB bit,rel
Jump if direct bit is not set
30
3
2
2
2
JBC bit,direct rel
Jump if direct bit is set and clear bit
10
3
2
CJNE A,direct rel
Compare direct byte to A and jump if not equal
B5
3
2
CJNE A,#data rel
CJNE Rn,#data rel
Compare immediate to A and jump if not equal
Compare immed. to reg. and jump if not equal
B4
B8-BF
3
3
CJNE @Ri,#data rel
Compare immed. to ind. and jump if not equal
B6-B7
3
2
2
2
DJNZ Rn,rel
Decrement register and jump if not zero
D8-DF
2
2
DJNZ direct,rel
NOP
Decrement direct byte and jump if not zero
No operation
D5
00
3
1
2
1
Mnemonic
CLR C
Table 2-5: Boolean manipulation
Description
Clear carry flag
Code
C3
CLR bit
Clear direct bit
C2
2
Cycles
1
1
SETB C
Set carry flag
D3
1
1
SETB bit
CPL C
Set direct bit
Complement carry flag
D2
B3
2
1
CPL bit
Complement direct bit
B2
2
1
1
1
ANL C,bit
AND direct bit to carry flag
82
2
2
ANL C,/bit
ORL C,bit
AND complement of direct bit to carry
OR direct bit to carry flag
B0
72
2
2
2
2
ORL C,/bit
OR complement of direct bit to carry
A0
2
2
Bytes
1
MOV C,bit
Move direct bit to carry flag
A2
2
1
MOV bit,C
Move carry flag to direct bit
92
2
2
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 14 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
3. Memory Structure
The SM8952B memory structure follows general 8052 structure. It is 8KB program memory.
3.1
Program Memory
The SM8952B has 8KB on-chip flash memory which can be used as general program memory. As shown in Fig.
3-1.
1FFF
8K Program
Memory space
Flash
0000
Fig. 3-1: SM8952B programmable Flash
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 15 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
3.2
Data Memory
The SM8952B has 256B on-chip SRAM. As shown in Fig. 3-2
FF
FF
Higher 128 Bytes (Accessed by
indirect addressing mode only)
SFR (Accessed by direct addressing
mode only)
80
80
7F
Lower 128 Bytes (Accessed by
direct & indirect addressing mode )
00
Fig. 3-2: RAM architecture
3.3
Data memory - lower 128 byte (00h to 7Fh)
Data memory 00h to FFh is the same as 8052.
The address 00h to 7Fh can be accessed by direct and indirect addressing modes.
Address 00h to 1Fh is register area.
Address 20h to 2Fh is memory bit area.
Address 30h to 7Fh is for general memory area.
3.4
Data memory - higher 128 byte (80h to FFh)
The address 80h to FFh can be accessed by indirect addressing mode.
Address 80h to FFh is data area.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 16 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
4.
CPU Engine
The SM8952B engine is composed of four components:
(1) Control unit
(2) Arithmetic – logic unit
(3) Memory control unit
(4) RAM and SFR control unit
The SM8952B engine allows to fetch instruction from program memory and to execute using RAM or SFR. The
following chapter describes the main engine register.
Mnemonic
ACC
B
PSW
SP
DPL
DPH
4.1
Description
Accumulator
B register
Program status
word
Stack Pointer
Data pointer low
Data pointer high
Dir.
Bit 7
E0h
F0h
ACC.7
B.7
D0h
CY
Bit 6
Bit 5
8051 Core
ACC.6 ACC.5
B.6
B.5
AC
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
ACC.4
B.4
ACC.3
B.3
ACC.2
B.2
ACC.1
B.1
ACC.0
B.0
00H
00H
OV
PSW.1
P
00H
F0
RS[1:0]
81h
82h
83h
SP[7:0]
DPL[7:0]
DPH[7:0]
07H
00H
00H
Accumulator
ACC is the Accumulator register. Most instructions use the accumulator to store the operand.
Mnemonic: ACC
7
6
ACC.7 ACC.6
5
ACC05
4
ACC.4
3
ACC.3
2
ACC.2
1
ACC.1
Address: E0h
0
Reset
ACC.0
00h
ACC[7:0]: The A (or ACC) register is the standard 8052 accumulator.
4.2
B Register
The B register is used during multiply and divide instructions. It can also be used as a scratch pad register to store
temporary data.
Mnemonic: B
7
6
B.7
B.6
5
B.5
4
B.4
3
B.3
2
B.2
1
B.1
Address: F0h
0
Reset
B.0
00h
B[7:0]: The B register is the standard 8052 register that serves as a second accumulator.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 17 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
4.3
Program Status Word
Mnemonic: PSW
7
6
CY
AC
5
F0
4
RS [1:0]
3
2
OV
1
F1
Address: D0h
0
Reset
P
00h
CY: Carry flag.
AC: Auxiliary Carry flag for BCD operations.
F0: General purpose Flag 0 available for user.
RS[1:0]: Register bank select, used to select working register bank.
RS[1:0]
Bank Selected
Location
00
Bank 0
00h – 07h
01
Bank 1
08h – 0Fh
10
Bank 2
10h – 17h
11
Bank 3
18h – 1Fh
OV: Overflow flag.
F1: General purpose Flag 1 available for user.
P: Parity flag, affected by hardware to indicate odd/even number of “one” bits in the
Accumulator, i.e. even parity.
4.4
Stack Pointer
The stack pointer is a 1-byte register initialized to 07h after reset. This register is incremented before PUSH and
CALL instructions, causing the stack to start from location 08h.
Mnemonic: SP
7
6
5
4
SP [7:0]
3
2
1
Address: 81h
0
Reset
07h
SP[7:0]: The Stack Pointer stores the scratchpad RAM address where the stack begins. In other
words, it always points to the top of the stack.
4.5
Data Pointer
The data pointer (DPTR) is 2-bytes wide. The lower part is DPL, and the highest is DPH. It can be loaded as a 2byte register (e.g. MOV DPTR, #data16) or as two separate registers (e.g. MOV DPL,#data8). It is generally used
to access the external code or data space (e.g. MOVC A,@A+DPTR or MOVX A,@DPTR respectively).
Mnemonic: DPL
7
6
5
3
DPL [7:0]
2
1
Address: 82h
0
Reset
00h
4
3
DPH [7:0]
2
1
Address: 83h
0
Reset
00h
4
DPL[7:0]: Data pointer Low
Mnemonic: DPH
7
6
5
DPH [7:0]: Data pointer High
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 18 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
5. GPIO
Port 0 ~ Port 3 are the general purpose IO of this controller. Most of the ports are multiplexed with the other
outputs, e.g., Port 3[0] is also used as RXD in the UART application. Port0 is open-drain in the input and output
high condition, so external pull-up resistors are required. As for the other ports, the pull-up resistors are built
internally.
For general purpose applications, every pin can be assigned to either high or low independently
because their SFRs are bit addressable as given below：
Mnemonic: P0
7
6
P0.7
P0.6
5
P0.5
4
P0.4
3
P0.3
2
P0.2
1
P0.1
Address: 80h
0
Reset
P0.0
FFh
P0.7~ 0: Port0 [7] ~ Port0[0]
Mnemonic: P1
7
6
P1.7
P1.6
5
P1.5
4
P1.4
3
P1.3
2
P1.2
1
P1.1
Address: 90h
0
Reset
P1.0
FFh
4
P2.4
3
P2.3
2
P2.2
1
P2.1
Address: A0h
0
Reset
P2.0
FFh
4
P3.4
3
P3.3
2
P3.2
1
P3.1
Address: B0h
0
Reset
P3.0
FFh
P1.7~ 0: Port1 [7] ~ Port1 [0]
Mnemonic: P2
7
6
P2.7
P2.6
5
P2.5
P2.7~ 0: Port2 [7] ~ Port2 [0]
Mnemonic: P3
7
6
P3.7
P3.6
5
P3.5
P3.7~ 0: Port3 [7] ~ Port3 [0]
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 19 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
6. Timer 0 and Timer 1
The SM8952B has three 16-bit timer/counter registers: Timer 0, Timer 1 and Timer 2. All can be configured for
counter or timer operations.
In timer mode, the Timer 0 register or Timer 1 register is incremented every machine cycles, due to 12 oscillator
periods in a machine cycle, the count rate is 1/12 of the oscillator frequency. If in 6T mode, the count rate is 1/6 of
the oscillator frequency.
In counter mode, the register is incremented when the falling edge is observed at the corresponding input pin T0 or
T1. Since it takes 2 machine cycles to recognize a 1-to-0 event, the maximum input count rate is 1/2 of the
oscillator frequency. There are no restrictions on the duty cycle, however to ensure proper recognition of 0 or 1
state, an input should be stable for at least 1 machine cycle.
Four operating modes can be selected for Timer 0 and Timer 1. Two Special Function registers (TMOD and TCON)
are used to select the appropriate mode.
Mnemonic
Description
Dir.
TL0
TH0
TL1
TH1
TMOD
Timer 0 , low byte
Timer 0 , high byte
Timer 1 , low byte
Timer 1 , high byte
Timer Mode Control
Timer/Counter
Control
8Ah
8Ch
8Bh
8Dh
89h
GATE
C/T
88h
TF1
TR1
TCON
6.1
Bit 7
Bit 6
Bit 5
Timer 0 and 1
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
M1
TL0[7:0]
TH0[7:0]
TL1[7:0]
TH1[7:0]
M0
GATE
C/T
M1
M0
00H
00H
00H
00H
00H
TF0
TR0
IT1
IE0
IT0
00H
IE1
Timer/counter mode control register (TMOD)
Mnemonic: TMOD
7
6
5
GATE
C/T
M1
Timer 1
4
M0
3
GATE
2
1
C/T
M1
Timer 0
Address: 89h
0
Reset
M0
00h
GATE: If set, enables external gate control (pin INT0 or INT1 for Counter 0 or 1,
respectively). When INT0 or INT1 is high, and TRx bit is set (see TCON
register), a counter is incremented every falling edge on T0 or T1 input pin.
C/T: Selects Timer or Counter operation. When set to 1, a counter operation is
performed, when cleared to 0, the corresponding register will function as a
timer.
M1
0
0
1
M0
0
Mode
Mode0
1
0
Mode1
Mode2
Function
13-bit counter/timer, with 5 lower bits in TL0 or
TL1 register and 8 bits in TH0 or TH1 register
(for Timer 0 and Timer 1, respectively). The 3
high order bits of TL0 and TL1 are hold at
zero.
16-bit counter/timer.
8-bit auto-reload counter/timer. The reload
value is kept in TH0 or TH1, while TL0 or TL1
is incremented every machine cycle. When
TLx overflows, a value from THx is copied to
TLx.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 20 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
1
6.2
1
Mode3
If Timer 1 M1 and M0 bits are set to 1, Timer 1
stops. If Timer 0 M1 and M0 bits are set to 1,
Timer 0 acts as two independent 8 bit timers /
counters.
Timer/counter control register (TCON)
Mnemonic: TCON
7
6
5
TF1
TR1
TF0
4
TR0
3
IE1
2
IT1
1
IE0
Address: 88h
0
Reset
IT0
00h
TF1: Timer 1 overflow flag set by hardware when Timer 1 overflows. This flag can
be cleared by software and is automatically cleared when interrupt is
processed.
TR1: Timer 1 Run control bit. If cleared, Timer 1 stops.
TF0: Timer 0 overflow flag set by hardware when Timer 0 overflows. This flag can
be cleared by software and is automatically cleared when interrupt is
processed.
TR0: Timer 0 Run control bit. If cleared, Timer 0 stops.
IE1: Interrupt 1 edge flag. Set by hardware, when falling edge on external pin
INT1 is observed. Cleared when interrupt is processed.
IT1: Interrupt 1 type control bit. Selects falling edge or low level on input pin to
cause interrupt. IT1=1, interrupt 1 select falling edge trigger. IT1=0, interrupt1
select low level trigger.
IE0: Interrupt 0 edge flag. Set by hardware, when falling edge on external pin
INT0 is observed. Cleared when interrupt is processed.
IT0: Interrupt 0 type control bit. Selects falling edge or low level on input pin to
cause interrupt. IT0=1, interrupt 0 select falling edge trigger. IT0=0, interrupt
0 select low level trigger.
6.3
Mode 0 (13-bit Counter/Timer)
The timer register is configured as a 13-bit register. As the count rolls over from all 1s to all 0s, it sets the timer
interrupt flag TFx. The counted input is enabled to the timer when TRx = 1 and either GATE=0 or INTx = 1. Mode 0
operation is the same for Timer0 and Timer1.
Fig. 6-1: Mode 0 -13 bit Timer / counter operation
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 21 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
6.4
Mode 1 (16-bit Counter/Timer)
Mode1 is the same as Mode0, except that the timer register is being run with all 16 bits.
Fig. 6-2: Mode 1 16 bit Counter/Timer operation
6.5
Mode 2 (8-bit auto-reload Counter/Timer)
Mode 2 configures the timer register as an 8-bit counter(TLx) with automatic reload. Overflow from TLx not only set
TFx, but also reload TLx with the content of THx, which is determined by software. The reload leaves THx
unchanged. Mode 2 operation is the same for Timer0 and Timer1.
Fig. 6-3: Mode 2 8-bit auto-reload Counter/Timer operation.
6.6
Mode 3 (Timer 0 acts as two independent 8 bit Timers / Counters)
Timer1 in Mode3 simply holds its count, the effect is the same as setting TR1 = 1. Timer0 in Mode 3 enables TL0
and TH0 as two separate 8-bit counters. TL0 uses the Timer0 control bits such like C/T, GATE, TR0, INT0 and TF0.
TH0 is locked into a timer function (can not be external event counter) and take over the use of TR1, TF1 from
Timer1. TH0 now controls the Timer1 interrupt.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 22 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Fig. 6-4: Mode 3 Timer 0 acts as two independent 8 bit Timers / Counters operatin
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 23 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
7.
Timer 2
Timer2 is a 16-bit timer/counter which can operate as either an event timer or an event counter as selected by
C/T2in the special function register T2CON.
Mnemonic
TL2
TH2
RCAP2L
RCAP2H
T2MOD
T2CON
Description
Timer 2 , low
byte
Timer 2 , high
byte
Reload and
capture data low
byte
Reload and
capture data
high byte
Timer 2 mode
Timer 2 control
register
Dir.
Bit 7
Bit 6
Bit 5
Bit 4
Serial interface 0 and 1
Bit 3
Bit 2
Bit 1
Bit 0
RST
CCh
TL2[7:0]
00h
CDh
TH2[7:0]
00h
CAh
RCAP2L[7:0]
00h
CBh
RCAP2H[7:0]
00h
C9h
-
-
-
-
C8h
TF2
EXF2
RCLK
TCLK
Mnemonic: T2MOD
7
6
5
-
4
-
3
-
2
-
EXEN
2
1
T2OE
-
T2OE
TR2
C/ T2
DCEN
CP/
RL2
Address: 98h
0
Reset
DCEN
00H
T2OE: Timer 2 Output Enable bit. It enables Timer2 overflow rate to toggle P1.0.
DCEN: Down Count Enable bit. When set, this allows Timer2 to be configured as an up/down
Counter.
Mnemonic: T2CON
7
6
5
TF2
EXF2
RCLK
4
3
2
1
TCLK
EXEN2
TR2
C/ T2
Address: 98h
0
Reset
CP/
00H
RL2
TF2: Timer 2 overflow flag is set by a Timer 2 overflow and must be cleared by software. TF2
will not be set when either RCLK = 1 or TCLK = 1.
EXF2: Timer 2 external flag is set when either a capture or reload is caused by a negative
transition on T2EX and EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will
cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must be cleared by
software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1).
RCLK: Receive clock enable. When set, causes the serial port to use Timer 2 overflow pluses
for its receive clock in serial port Modes 1 and 3. RCLK = 0 causes Timer 1 overflows to
be used for the receive clock.
TCLK: Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses
for it’s transmit clock in serial port Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to
be used for the transmit clock.
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 24 -
x0h
00h
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
EXEN2: Timer 2 external enable. When set, allows a capture or reload to occur as a result of a
negative transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 =
0 causes Timer 2 to ignore events at T2EX.
TR2: Start/Stop control for Timer 2. TR2 = 1 starts the timer.
C/ T2 : Timer or counter select for Timer 2. C/ T2 = 0 for timer function. C/ T2 = 1 for external
event counter (falling edge triggered).
CP/ RL2 : Capture/Reload select. CP/ RL2 = 1 causes captures to occur on negative transitions at
T2EX if EXEN2 = 1. CP/ RL2 = 0 causes automatic reloads to occur when Timer 2
overflows or negative transitions occur at T2EX when EXEN2 = 1. When either RCLK or
TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow.
RCLK + TCLK
x
1
0
0
0
7.1
CP/RL2
x
x
1
0
0
Table 7-1 : Timer 2 Operating Modes
TR2
DCEN
Mode
0
x
OFF
1
0
Baud-Rate Generation
1
0
Capture
1
0
Auto-Reload Up-only
1
1
Auto-Reload Up/Down
Capture mode
In the capture mode, there are two options selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 is a 16-bit
timer or counter which upon overflow sets bit TF2 in T2CON. This bit can then be used to generate an interrupt. If
EXEN2 = 1, Timer 2 still does the above, but with the added feature that a 1-to-0 transition at external input T2EX
causes the current value in TH2 and TL2 to be captured into RCAP2H and RCAP2L, respectively. In addition, the
transition at T2EX causes bit EXF2 in T2CON to be set. The EXF2 bit, like TF2, can generate an interrupt.
Fosc/12
T2 pin
C/T2=0
TL2
(8 BITS)
C/T2=1
TH2
(8 BITS)
TF2
TR2
Timer2 Interrupt
RCAP2L RCAP2H
Transition
Detector
T2 EX pin
EXF2
EXEN2
Timier2 in Capture Mode
Fig. 7-1： Timer 2 in capture mode
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M077
Ver A SM8952B 01/22/2014
- 25 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
7.2
Auto-reload (Up or Down Counter)
Timer 2 can be programmed to count up or down when configured in its 16-bit auto-reload mode. This feature is
invoked by a bit named DCEN (Down Counter Enable) located in the SFR T2MOD. Upon reset, the DCEN bit is set
to 0 so that Timer 2 will default to count up. When DCEN is set, Timer 2 can count up or down depending on the
value of the T2EX pin.
Fig. 7-2 shows Timer 2 automatically counting up when DCEN = 0. In this mode there are two options selected by
bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to FFFFh and then sets the TF2 bit upon overflow. The
overflow also causes the timer registers to be reloaded with the 16-bit value in RCAP2H and RCAP2L. The values
in RCAP2H and RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be triggered either by an
overflow or by a 1-to-0 transition at external input T2EX. This transition also sets the EXF2 bit. Both the TF2 and
EXF2 bits can generate an interrupt if enabled.
Setting the DCEN bit enables Timer 2 to count up or down as shown in Fig. 7-3. In this mode the T2EX pin controls
the direction of count. A logic 1 at T2EX makes Timer 2 count up. The timer will overflow at FFFFh and set the TF2
bit. This overflow also causes the 16-bit value in RCAP2H and RCAP2L to be reloaded into the timer registers, TH2
and TL2, respectively.
A logic 0 at T2EX makes Timer 2 count down. Now the timer underflows when TH2 and TL2 are equal to the values
stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes FFFFH to be reloaded into the timer
registers.
The EXF2 bit toggles whenever Timer 2 overflows or underflows. This bit can be used as a 17th bit of resolution if
desired. In this operating mode, EXF2 does not flag an interrupt.
Fosc/12
T2 pin
C/T2=0
TL2
(8 BITS)
C/T2=1
TR2
TH2
(8 BITS)
TF2
RELOAD
Timer2 Interrupt
RCAP2L RCAP2H
Transition
Detector
T2 EX pin
EXF2
EXEN2
Timier2 in Auto Reload Mode
(DCEN=0)
Fig. 7-2：Timer 2 in auto reload mode (DCEN=0)
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ISSFD-M077
Ver A SM8952B 01/22/2014
- 26 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
FFH
FFH
EXF2
Fosc/12
T2 pin
C/T2=0
TL2
C/T2=1
TH2
TF2
Timer2
interrupt
Count Direction
1 = UP
0 = DOWN
TR2
RCAP2L
RCAP2H
T2EX PIN
Timier2 in Auto Reload Mode
(DCEN=1)
Fig. 7-3： Timer 2 in auto reload mode (DCEN=1)
7.3
Programmable clock out
A 50% duty cycle clock can be programmed to come out on P1.0. This pin, besides begin a regular I/O pin, has two
alternate functions. It can be programmed (1) to input the external clock for Timer/Counter 2 or (2) to output a 50%
duty cycle clock. An example is that the clock output ranges from 61Hz to 4MHz at a 16MHz oscillator frequency if
in 12T mode.
To configure the Timer/Counter 2 as a clock generator, bit C/ T 2 (T2CON.1) must be cleared and bit
T2OE(T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and stops the timer.
The Clock-Out frequency depends on the oscillator frequency and the reload value of Timer 2 capture registers
(RCAP2H, RCAP2L) as shown in this equation:
Clock-Out Frequency =
Oscillator Frequency
4 × (65536 − RCAP 2 H , RCAP 2 L)
In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This is similar to when Timer 2 is used as a
baud-rate generator. It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously.
Note, however, that the baud-rate and clock-out frequencies can not be determined independently from one
another since they both use RCAP2H and RCAP2L.
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ISSFD-M077
Ver A SM8952B 01/22/2014
- 27 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Fig. 7-4： Timer 2 in clock-out mode
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
8. Serial interface – UART
The serial buffer consists of two separate registers, a Transmit buffer and a receive buffer.
Writing data to the Special Function Register SBUF sets this data in serial output buffer and starts the transmission.
Reading from the SBUF reads data from the serial receive buffer. The serial port can simultaneously Transmit and
receive data. It can also buffer 1 byte at receive, which prevents the receive data from being lost if the CPU reads
the first byte before transmission of the second byte is completed.
Mnemonic
Description
Dir.
Bit 7
PCON
Power control
Serial Port control
register
Serial Port data
buffer
87H
SMOD
98H
SM0
SCON
SBUF
Bit 6
Bit 5
Serial interface
-
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
-
GF1
GF0
PD
IDLE
00H
SM1
REN
TB8
RB8
TI
RI
00H
SM2
99H
SBUF[7:0]
Mnemonic: SCON
7
6
5
SM0
SM1
SM2
4
REN
3
TB8
2
RB8
1
TI
00H
Address: 98h
0
Reset
RI
00H
SM0, SM1: Serial Port 0 mode selection.
SM0
SM1 Mode
0
0
0
0
1
1
1
0
2
1
1
3
The 4 modes in UART, Mode 0 ~ 3, are explained later.
SM2: Enables multiprocessor communication feature
REN: If set, enables serial reception. Cleared by software to disable reception.
TB8: The 9th transmitted data bit in modes 2 and 3. Set or cleared by the CPU depending on
the function it performs such as parity check, multiprocessor communication etc.
RB8: In modes 2 and 3, it is the 9th data bit received. In mode 1, if SM2 is 0, RB8 is the stop
bit. In mode 0, this bit is not used. Must be cleared by software.
TI: Transmit interrupt flag, set by hardware after completion of a serial transfer. Must be
cleared by software.
RI: Receive interrupt flag, set by hardware after completion of a serial reception. Must be
cleared by software.
8.1
Serial interface
The Serial Interface can operate in the following 4 modes:
SM0
0
0
1
1
SM1
0
1
0
1
Mode
0
1
2
3
Description
Shift register
8-bit UART
9-bit UART
9-bit UART
Board Rate
Fosc/12
Variable
Fosc/32 or Fosc/64
Variable
Here Fosc is the crystal or oscillator frequency.
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
The serial port of Maryland is full duplex, can transmit and receive simultaneously. The serial port receive and
transmit share the same SFR – SBUF, but actually there is two SBUF in the chip, one is for transmit and the other
is for receive. The serial port can be operated in 4 different modes.
8.1.1
Mode 0
Pin RXD serves as input and output. TXD outputs the shift clock. 8 bits are transmitted with LSB first. The baud
rate is fixed at 1/12 of the crystal frequency. Reception is initialized in Mode 0 by setting the flags in SCON as
follows: RI = 0 and REN = 1. In other modes, a start bit when REN = 1 starts receiving serial data. As shown in Fig.
8-1 and Fig. 8-2
Fig. 8-1: Transmit mode 0
Fig. 8-2: Receive mode 0
8.1.2
Mode 1
Pin RXD serves as input, and TXD serves as serial output. No external shift clock is used, 10 bits are transmitted: a
start bit (always 0), 8 data bits (LSB first), and a stop bit (always 1). On receive, a start bit synchronizes the
transmission, 8 data bits are available by reading SBUF, and stop bit sets the flag RB8 in the Special Function
Register SCON. In mode 1 either internal baud rate generator or timer 1 can be use to specify baud rate. As shown
in Fig. 8-3 and Fig. 8-4
Fig. 8-3: Transmit mode 1
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Fig. 8-4: Receive mode 1
8.1.3
Mode 2
This mode is similar to Mode 1, with two differences. The baud rate is fixed at 1/32 (SMOD=1) or 1/64(SMOD=0) of
oscillator frequency and 11 bits are transmitted or received: a start bit (0), 8 data bits (LSB first), a programmable
9th bit, and a stop bit (1). The 9th bit can be used to control the parity of the serial interface: at transmission, bit
TB8 in SCON is output as the 9th bit, and at receive, the 9th bit affects RB8 in Special Function Register SCON.
8.1.4
Mode 3
The only difference between Mode 2 and Mode 3 is that in Mode 3 either internal baud rate generator or timer 1
can be use to specify baud rate. As shown in Fig. 8-5 and Fig. 8-6.
Fig. 8-5: Transmit modes 2 and 3
Fig. 8-6: Receive modes 2 and 3
8.2
Multiprocessor Communication of Serial Interface
The feature of receiving 9 bits in Modes 2 and 3 of Serial Interface can be used for multiprocessor communication.
In this case, the slave processors have bit SM2 in SCON set to 1. When the master processor outputs slave’s
address, it sets the 9th bit to 1, causing a serial port receive interrupt in all the slaves. The slave processors
compare the received byte with their network address. If there is a match, the addressed slave will clear SM2 and
receive the rest of the message, while other slaves will leave SM2 bit unaffected and ignore this message. After
addressing the slave, the host will output the rest of the message with the 9th bit set to 0, so no serial port receive
interrupt will be generated in unselected slaves.
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
8.3
Baud Rate Generator
8.3.1
Serial interface Mode 0
Baud Rate =
8.3.2
Serial interface Mode 2
Baud Rate =
8.3.3
Fosc
12
2 SMOD
× (Fosc)
64
Serial interface Mode 1 and 3
8.3.3.1
Using Timer 1 to Generate Baud Rates.
8.3.3.2
Using Timer 2 to Generate Baud Rates.
2 SMOD
2 SMOD
Fosc
Baud Rate =
× (Timer 1 overflow rate) =
×
32
32
12 × [256 − TH 1]
Baud Rate =
Timer 2 overflow rate
Fosc
=
32
32 × [65536 - (RCAP2H, RCAP2L)]
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ISSFD-M077
Ver A SM8952B 01/22/2014
- 32 -
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
9. Interrupt
The SM8952B provides 6 interrupt sources with two priority levels. Each source has its own request flag(s) located
in a special function register. Each interrupt requested by the corresponding flag could individually be enabled or
disabled by the enable bits in SFR’s IE.
When the interrupt occurs, the engine will vector to the predetermined address as given in Table 9-1. Once
interrupt service has begun, it can be interrupted only by a higher priority interrupt. The interrupt service is
terminated by a return from instruction RETI. When an RETI is performed, the processor will return to the
instruction that would have been next when interrupt occurred.
When the interrupt condition occurs, the processor will also indicate this by setting a flag bit. This bit is set
regardless of whether the interrupt is enabled or disabled. Each interrupt flag is sampled once per machine cycle,
and then samples are polled by hardware. If the sample indicates a pending interrupt when the interrupt is enabled,
then interrupt request flag is set. On the next instruction cycle the interrupt will be acknowledged by hardware
forcing an LCALL to appropriate vector address.
Interrupt response will require a varying amount of time depending on the state of microcontroller when the
interrupt occurs. If microcontroller is performing an interrupt service with equal or greater priority, the new interrupt
will not be invoked. In other cases, the response time depends on current instruction.
Priority
level
1 (highest)
Table 9-1: Interrupt vectors
Interrupt Vector
Interrupt Request Flags
Address
IE0 – External interrupt 0
0003h
Interrupt Number
*(use Keil C Tool)
0
2
TF0 – Timer 0 interrupt
000Bh
1
3
IE1 – External interrupt 1
0013h
2
4
TF1 – Timer 1 interrupt
001Bh
3
5
RI0/TI 0– Serial channel 0 interrupt
0023h
4
6
TF2/EXF2 – Timer 2 interrupt
002Bh
5
*See Keil C about C51 User’s Guide about Interrupt Function description
Mnemonic
IE
IP
Description
Interrupt Enable
register
Interrupt priority
register
Mnemonic: IE
7
6
EA
-
Dir.
Bit 7
A8H
EA
-
B8H
-
-
5
ET2
Bit 6
Bit 5
Interrupt
4
ES
3
ET1
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RST
ET2
ES
ET1
EX1
ET0
EX0
00H
PT2
PS
PT1
PX1
PT0
PX0
00H
2
EX1
1
ET0
Address: A8h
0
Reset
EX0
00h
EA: EA=0 – Disable all interrupt.
EA=1 – Enable all interrupt.
ET2: ET2=0 – Disable Timer 2 overflow or external reload interrupt.
ET2=1 – Enable Timer 2 overflow or external reload interrupt.
ES: ES=0 – Disable Serial channel interrupt.
ES=1 – Enable Serial channel interrupt.
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
ET1: ET1=0 – Disable Timer 1 overflow interrupt.
ET1=1 – Enable Timer 1 overflow interrupt.
EX1: EX1=0 – Disable external interrupt 1.
EX1=1 – Enable external interrupt 1.
ET0: ET0=0 – Disable Timer 0 overflow interrupt.
ET0=1 – Enable Timer 0 overflow interrupt.
EX0: EX0=0 – Disable external interrupt 0.
EX0=1 – Enable external interrupt 0.
Mnemonic: IP
7
6
-
5
PT2
4
PS
3
PT1
2
PX1
1
PT0
Address: B8h
0
Reset
PX0
00H
PT2: Timer2 interrupt priority bit.
PS: Serial port interrupt priority bit.
PT1: Timer1 interrupt priority bit.
PX1: External interrupt 1 priority bit.
PT0: Timer 0 interrupt priority bit.
PX0: External interrupt 0 priority bit.
IP.x
1
0
Interrupt Priority Table
Priority Level
1
(highest)
2
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
10. Watch Dog Timer
The Watch Dog Timer (WDT) is an 16-bit free-running counter that generate reset signal if the counter overflows.
The WDT is useful for systems which are susceptible to noise, power glitches, or electronics discharge which
causing software dead loop or runaway. The WDT function can help user software recover from abnormal software
condition. The WDT is different from Timer0, Timer1 and Timer2 of general 8052. To prevent a WDT reset can be
done by software periodically clearing the WDT counter. User should check WDR bit of SCONF register whenever
un-predicted reset happened. After an external reset the watchdog timer is disabled and all registers are set to
zeros.
The WDT has selectable divider input for the time base source clock. To select the divider input, the setting of bit2
~ bit0 (PS[2:0]) of Watch Dog Timer Control Register (WDTC) should be set accordingly. As shown in Table 10-1.
To enable the WDT is done by setting 1 to the bit 7 (WDTE) of WDTC. After WDTE set to 1, the 16-bit counter
starts to count with the selected time base source clock which set by PS2~PS0. It will generate a reset signal when
overflows. The WDTE bit will be cleared to 0 automatically when SM8952B been reset, either hardware reset or
WDT reset.
To reset the WDT is done by setting 1 to the bit 5 (CLEAR) of WDTC. This will clear the content of the 16-bit
counter and let the counter re-start to count from the beginning.
PS[2:0]
000
001
010
011
100
101
110
111
Table 10-1: WDT time-out period
Divider
Time period @ 40MHz
(dividing of Fosc)
8
13.1ms
16
26.21ms
32
52.42ms
64
104.8ms
128
209.71ms
256
419.43ms
512
838.86ms
1024
1677.72ms
Clear
WDTF = 0
1. Power on reset
2. External reset
3. Software write “0”
Fosc
WDR
Set WDR = 1
1
WDTCLK
2 PS[2:0]+3
PS[2:0]
WDTC
WDT
Counter
Enable/Disable
WDT
WDTEN
WDT
time-out
select
WDT time-out
reset
Refresh
WDT Counter
CLR
Fig. 10-1: Watchdog timer block diagram
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ISSFD-M077
Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Mnemonic
WDTC
SCONF
Description
Watchdog timer
control register
System Control
Register
Dir.
Bit 7
9FH
WDTE
-
BFH
WDR
-
Mnemonic: WDTC
7
6
5
WDTE
CLEAR
Bit 6
Bit 5
Watchdog Timer
4
-
Bit 4
Bit 3
CLEAR
-
-
-
-
-
3
-
2
1
PS [2:0]
Bit 2
Bit 1
Bit 0
PS [2:0]
-
-
00H
ALEI
Address: 9Fh
0
Reset
00H
WDTE: Watch Dog Timer enable bit.
CLEAR: Watch Dog Timer clear bit.
If CLEAR bit set to1, setting this bit the Watchdog timer counter clear and re-start to
count from the Beginning.
PS[2:0]: Watch Dog timer over flow period setting.
Mnemonic: SCONF
7
6
WDR
5
-
4
-
3
-
2
-
Address: BFh
0
Reset
ALEI
00H
1
-
RST
WDR Watch Dog Timer Reset.
When system reset by Watch Dog Timer overflow, WDR will be set to 1.
User should check WDR bit whenever un-predicted reset happened.
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ISSFD-M077
Ver A SM8952B 01/22/2014
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00H
SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
11. Power Management Unit
Power management unit serves two power management modes, Idle and Power Down, for the users to do power
saving function.
Mnemonic: PCON
7
6
SMOD
-
5
-
4
-
3
GF1
2
GF0
1
PD
Address: 87h
0
Reset
IDLE
00h
GF1: General-purpose flag bit.
GF0: General-purpose flag bit.
PD: Power Down mode control bit. Setting this bit turning on the PD Mode.
PD bit is always read as 0
IDLE: Idle mode control bit. Setting this bit turning on the Idle Mode.
Idle bit is always read as 0
11.1 Idle mode
An instruction that sets PCON.0 causes that to be the last instruction executed before going into the idle mode, the
internal clock is gated off to the CPU but not to the interrupt, timer and serial port functions.
There are two ways to terminate the idle. Activation of any enabled interrupt will cause PCON.0 to be cleared by
hardware, terminating the idle mode. The interrupt will be serviced, and following RETI, the next instruction to be
executed will be the one following the instruction that put the device into idle. Another way to wake-up from idle is
to pull RESET high to generate internal hardware reset.
11.2 Power Down mode
An instruction that sets PCON.1 cause that to be the last instruction executed before going into the Power-Down
mode. In the power-down mode, the on-chip oscillator is stopped. The contents of on-chip RAM and SFRs are
maintained. Be carefully to keep RESET pin active for at least 10ms in order for a stable clock.
The power-down mode can be woken-up by RESET pin. When it is woken-up by RESET, the program will execute
from the address 0000H.
Mode
Idle
Idle
Power-Down
Power-Down
Pin Status in IDLE Mode and Power-Down Mode
Program Memory
ALE
PSEN
Port0
Port1
Internal
1
1
Data
Data
External
1
1
Float
Data
Internal
0
0
Data
Data
External
0
0
Float
Data
Port2
Data
Address
Data
Data
Port3
Data
Data
Data
Data
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Ver A SM8952B 01/22/2014
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SM8952B
8-Bit Micro-controller
8KB Flash
& 256B RAM embedded
Operating Conditions
Symbol
TA
VDD
Description
Min.
Typ.
Max.
Unit.
Operating temperature
-40
25
85
℃
Supply voltage
2.4
5.5
V
Remarks
Ambient temperature under bias
DC Characteristics
TA = -40℃ to 85℃, VCC = 5.0V
Symbol
Parameter
VIL1
Input Low Voltage
VIL2
Input Low Voltage
VIH1
Input High Voltage
VIH2
Input High Voltage
VOL1 Output Low Voltage
VOL2 Output Low Voltage
VOH1 Output High Voltage
VOH2
IIL
ITL
ILI
R RES
C IO
I CC
Output High Voltage
Logical 0 Input Current
Logical Transition
Current
Input Leakage Current
Reset Pull-down
Resistance
Pin Capacitance
Power Supply Current
Valid
port 0,1,2,3,#EA
RES, XTAL1
port 0,1,2,3,#EA
RES, XTAL1
port 0, ALE, #PSEN
port 1,2,3,
port 0
port
1,2,3,ALE,#PSEN
port 1,2,3
Min.
-0.5
0
2.0
70%Vcc
2.4
90%Vcc
2.4
90%Vcc
port 1,2,3
port 0, #EA
RES
Vdd
50
Max.
0.8
0.8
Vcc+0.5
Vcc+0.5
0.45
0.45
-75
Unit
V
V
V
V
V
V
V
V
V
V
uA
Test Conditions
IOL=3.2mA
IOL=1.6mA
IOH=-800uA
IOH=-80uA
IOH=-60uA
IOH=-10uA
Vin=0.45V
-650
uA
Vin=2.0V
±10
uA
0.45V<Vin<Vcc
300
Kohm
10
20
6.5
15
pF
mA
mA
uA
Freq=1MHz, Ta=25 ℃
Active mode, 16MHz
Idle mode, 16MHz
Power down mode
Note1: Under steady state (non-transient) conditions, IOL must be externally
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