參數(shù)資料
型號: MC16S2CPU20B1
廠商: FREESCALE SEMICONDUCTOR INC
元件分類: 微控制器/微處理器
英文描述: 16-BIT, 20.97 MHz, MICROCONTROLLER, PQFP100
封裝: TQFP-100
文件頁數(shù): 43/104頁
文件大?。?/td> 812K
代理商: MC16S2CPU20B1
MC68HC16S2
MOTOROLA
MC68HC16S2TS/D
43
Arbitration is performed by means of serial contention between values stored in individual module inter-
rupt arbitration (IARB) fields. Each module that can request interrupt service, including the SIM, has an
IARB field in its configuration register. IARB fields can be assigned values from %0000 to %1111. In
order to implement an arbitration scheme, each module that can request interrupt service must be
assigned a unique, non-zero IARB field value during system initialization. Arbitration priorities range
from %0001 (lowest) to %1111 (highest) — if the CPU recognizes an interrupt service request from a
source that has an IARB field value of %0000, a spurious interrupt exception is processed.
WARNING
Do not assign the same arbitration priority to more than one module. When two or
more IARB fields have the same non-zero value, the CPU16 interprets multiple
vector numbers at the same time, with unpredictable consequences.
Because the EBI manages external interrupt requests, the SIM IARB value is used for arbitration be-
tween internal and external interrupt requests. The reset value of IARB for the SIM is %1111, and the
reset IARB value for all other modules is %0000.
Although arbitration is intended to deal with simultaneous requests of the same priority, it always takes
place, even when a single source is requesting service. This is important for two reasons: the EBI does
not transfer the interrupt acknowledge read cycle to the external bus unless the SIM wins contention,
and failure to contend causes the interrupt acknowledge bus cycle to be terminated early, by a bus error.
When arbitration is complete, the module with the highest arbitration priority must terminate the bus
cycle. Internal modules place an interrupt vector number on the data bus and generate appropriate in-
ternal cycle termination signals. In the case of an external interrupt request, after the interrupt acknowl-
edge cycle is transferred to the external bus, the appropriate external device must decode the mask
value and respond with a vector number, then generate data and size acknowledge (DSACK) termina-
tion signals, or it must assert the autovector (AVEC) request signal. If the device does not respond in
time, the EBI bus monitor asserts the bus error signal (BERR), and a spurious interrupt exception is
taken.
Chip-select logic can also be used to generate internal AVEC or DSACK signals in response to interrupt
requests from external devices. Chip-select address match logic functions only after the EBI transfers
an interrupt acknowledge cycle to the external bus following IARB contention. If a module makes an
interrupt request of a certain priority, and the appropriate chip-select registers are programmed to gen-
erate AVEC or DSACK signals in response to an interrupt acknowledge cycle for that priority level, chip-
select logic does not respond to the interrupt acknowledge cycle, and the internal module supplies a
vector number and generates internal cycle termination signals.
For periodic timer interrupts, the PIRQL field in the periodic interrupt control register (PICR) determines
PIT priority level. A PIRQL value of %000 means that PIT interrupts are inactive. By hardware conven-
tion, when the CPU16 receives simultaneous interrupt requests of the same level from more than one
SIM source (including external devices), the periodic interrupt timer is given the highest priority, followed
by the IRQ pins. Refer to 3.4.6 Periodic Interrupt Timer for more information.
3.9.2 Interrupt Processing Summary
A summary of the interrupt processing sequence follows. When the sequence begins, a valid interrupt
service request has been detected and is pending.
A. The CPU finishes higher priority exception processing or reaches an instruction boundary.
B. The processor state is stacked, then the CCR PK extension field is cleared.
C. The interrupt acknowledge cycle begins:
F
re
e
sc
a
le
S
e
m
ic
o
n
d
u
c
to
r,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
n
c
..
.
相關(guān)PDF資料
PDF描述
MC68HC16X1CTH 16-BIT, MROM, 16.78 MHz, MICROCONTROLLER, PQFP120
MC68HC24VP 16 I/O, PIA-GENERAL PURPOSE, PDIP40
MC68HC33CFG 48 I/O, PIA-GENERAL PURPOSE, PQFP100
MC68HC33FG 48 I/O, PIA-GENERAL PURPOSE, PQFP100
MC68HC56FN 1 CHANNEL(S), LOCAL AREA NETWORK CONTROLLER, PQCC28
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC16XSD200FK 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:Dual 16 mOhm High Side Switch
MC16Z1CFC25B1 制造商:Rochester Electronics LLC 功能描述:- Bulk
MC16Z1CPV20B1 制造商:Rochester Electronics LLC 功能描述:16 BIT MCU, 1K RAM - Bulk
MC16Z3BCAG16 功能描述:16位微控制器 - MCU 16BIT MCU 4KRAM 8KROM RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風(fēng)格:SMD/SMT
MC-17 功能描述:TERM BARRIER 17CIRC DUAL ROW RoHS:是 類別:連接器,互連式 >> 接線座 - 隔板塊 系列:M 標(biāo)準包裝:10 系列:Beau™ 38780 端接塊類型:阻隔塊 電路數(shù):15 導(dǎo)線入口數(shù)目:30 間距:0.438"(11.12mm) 行數(shù):2 電流:15A 電壓:300V 線規(guī):14-22 AWG 頂部端子:螺釘 底部端子:焊片 阻擋層類型:雙壁(雙) 特點:法蘭 顏色:黑 包裝:散裝 安裝類型:通孔 工作溫度:- 材料 - 絕緣體:聚對苯二甲酸丁二酯(PBT),玻璃纖維增強型 材料可燃性額定值:UL94 V-0 其它名稱:038780-111538780-1115387801115