ST72F321BAR6T6 STMicroelectronics, ST72F321BAR6T6 Datasheet - Page 23
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ST72F321BAR6T6
Manufacturer Part Number
ST72F321BAR6T6
Description
MCU 8BIT 32KB FLASH/ROM 64-LQFP
Manufacturer
STMicroelectronics
Series
ST7r
Datasheet
1.ST72F321BK6T6.pdf
(187 pages)
Specifications of ST72F321BAR6T6
Core Processor
ST7
Core Size
8-Bit
Speed
8MHz
Connectivity
I²C, SCI, SPI
Peripherals
LVD, POR, PWM, WDT
Number Of I /o
48
Program Memory Size
32KB (32K x 8)
Program Memory Type
FLASH
Ram Size
1K x 8
Voltage - Supply (vcc/vdd)
3.8 V ~ 5.5 V
Data Converters
A/D 16x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
64-LQFP
Processor Series
ST72F3x
Core
ST7
Data Bus Width
8 bit
Data Ram Size
1 KB
Interface Type
I2C, SCI, SPI
Maximum Clock Frequency
8 MHz
Number Of Programmable I/os
48
Number Of Timers
2
Maximum Operating Temperature
+ 85 C
Mounting Style
SMD/SMT
Development Tools By Supplier
ST7232X-EVAL, ST7232X-SK/RAIS, ST72321B-D/RAIS, ST7MDT20-DVP3, ST7MDT20J-EMU3, ST7MDT20M-EMU3, STX-RLINK
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 16 Channel
For Use With
497-5046 - KIT TOOL FOR ST7/UPSD/STR7 MCU
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Lead Free Status / Rohs Status
Details
Other names
497-5582
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
ST72F321BAR6T6
Manufacturer:
STMicroelectronics
Quantity:
10 000
CENTRAL PROCESSING UNIT (Cont’d)
Stack Pointer (SP)
Read/Write
Reset Value: 01 FFh
The Stack Pointer is a 16-bit register which is al-
ways pointing to the next free location in the stack.
It is then decremented after data has been pushed
onto the stack and incremented before data is
popped from the stack (see
Since the stack is 256 bytes deep, the 8 most sig-
nificant bits are forced by hardware. Following an
MCU Reset, or after a Reset Stack Pointer instruc-
tion (RSP), the Stack Pointer contains its reset val-
ue (the SP7 to SP0 bits are set) which is the stack
higher address.
Figure 10. Stack Manipulation Example
@ 0100h
@ 01FFh
SP7
15
0
7
SP
SP6
0
Subroutine
Stack Higher Address = 01FFh
Stack Lower Address = 0100h
CALL
PCH
PCL
SP5
0
SP
SP4
0
SP3
Interrupt
0
Event
Figure
PCH
PCH
PCL
PCL
CC
X
A
SP2
0
2).
SP
ST72321BRx, ST72321BARx ST72321BJx, ST72321BKx
SP1
0
PUSH Y
SP0
PCH
PCH
PCL
PCL
8
1
0
CC
X
Y
A
SP
The least significant byte of the Stack Pointer
(called S) can be directly accessed by a LD in-
struction.
Note: When the lower limit is exceeded, the Stack
Pointer wraps around to the stack upper limit, with-
out indicating the stack overflow. The previously
stored information is then overwritten and there-
fore lost. The stack also wraps in case of an under-
flow.
The stack is used to save the return address dur-
ing a subroutine call and the CPU context during
an interrupt. The user may also directly manipulate
the stack by means of the PUSH and POP instruc-
tions. In the case of an interrupt, the PCL is stored
at the first location pointed to by the SP. Then the
other registers are stored in the next locations as
shown in
– When an interrupt is received, the SP is decre-
– On return from interrupt, the SP is incremented
A subroutine call occupies two locations and an in-
terrupt five locations in the stack area.
mented and the context is pushed on the stack.
and the context is popped from the stack.
POP Y
PCH
PCH
PCL
PCL
CC
Figure
A
X
2.
SP
IRET
PCH
PCL
SP
or RSP
RET
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