参数资料
型号: ST72F324LJ2T5
厂商: STMICROELECTRONICS
元件分类: 微控制器/微处理器
英文描述: 8-BIT, FLASH, 8 MHz, MICROCONTROLLER, PQFP44
封装: 10 X 10 MM, TQFP-44
文件页数: 75/154页
文件大小: 3519K
代理商: ST72F324LJ2T5
ST72324Lxx
27/154
INTERRUPTS (Cont’d)
Servicing Pending Interrupts
As several interrupts can be pending at the same
time, the interrupt to be taken into account is deter-
mined by the following two-step process:
– the highest software priority interrupt is serviced,
– if several interrupts have the same software pri-
ority then the interrupt with the highest hardware
priority is serviced first.
Figure 15 describes this decision process.
Figure 15. Priority Decision Process
When an interrupt request is not serviced immedi-
ately, it is latched and then processed when its
software priority combined with the hardware pri-
ority becomes the highest one.
Note 1: The hardware priority is exclusive while
the software one is not. This allows the previous
process to succeed with only one interrupt.
Note 2: RESET and TRAP can be considered as
having the highest software priority in the decision
process.
Different Interrupt Vector Sources
Two interrupt source types are managed by the
ST7 interrupt controller: the non-maskable type
(RESET, TRAP) and the maskable type (external
or from internal peripherals).
Non-Maskable Sources
These sources are processed regardless of the
state of the I1 and I0 bits of the CC register (see
Figure 14). After stacking the PC, X, A and CC
registers (except for RESET), the corresponding
vector is loaded in the PC register and the I1 and
I0 bits of the CC are set to disable interrupts (level
3). These sources allow the processor to exit
HALT mode.
TRAP (Non Maskable Software Interrupt)
This software interrupt is serviced when the TRAP
instruction is executed. It will be serviced accord-
ing to the flowchart in Figure 14.
RESET
The RESET source has the highest priority in the
ST7. This means that the first current routine has
the highest software priority (level 3) and the high-
est hardware priority.
See the RESET chapter for more details.
Maskable Sources
Maskable interrupt vector sources can be serviced
if the corresponding interrupt is enabled and if its
own interrupt software priority (in ISPRx registers)
is higher than the one currently being serviced (I1
and I0 in CC register). If any of these two condi-
tions is false, the interrupt is latched and thus re-
mains pending.
External Interrupts
External interrupts allow the processor to exit from
HALT low power mode. External interrupt sensitiv-
ity is software selectable through the External In-
terrupt Control register (EICR).
External interrupt triggered on edge will be latched
and the interrupt request automatically cleared
upon entering the interrupt service routine.
If several input pins of a group connected to the
same interrupt line are selected simultaneously,
these will be logically ORed.
Peripheral Interrupts
Usually the peripheral interrupts cause the MCU to
exit from HALT mode except those mentioned in
the “Interrupt Mapping” table. A peripheral inter-
rupt occurs when a specific flag is set in the pe-
ripheral status registers and if the corresponding
enable bit is set in the peripheral control register.
The general sequence for clearing an interrupt is
based on an access to the status register followed
by a read or write to an associated register.
Note: The clearing sequence resets the internal
latch. A pending interrupt (i.e. waiting for being
serviced) will therefore be lost if the clear se-
quence is executed.
PENDING
SOFTWARE
Different
INTERRUPTS
Same
HIGHEST HARDWARE
PRIORITY SERVICED
PRIORITY
HIGHEST SOFTWARE
PRIORITY SERVICED
1
相关PDF资料
PDF描述
ST72324BLJ4B5/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP32
ST72324BLJ4B6/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP32
ST72324BLJ4T1/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
ST72324BLJ4T5/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
ST72324BLJ4T6/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP44
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ST72F324LJ2T6 功能描述:8位微控制器 -MCU ST72F324L ST72324BL 3V RANGE 8B MCU RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ST72F324LJ4T6 功能描述:8位微控制器 -MCU ST72F324L ST72324BL 3V RANGE 8B MCU RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
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