- 您现在的位置：买卖IC网 > PDF目录97874 > EC000UM EC000 Core User＇s Manual (SCM68000) PDF资料下载
参数资料
| 型号： | EC000UM |
| 英文描述： | EC000 Core User＇s Manual (SCM68000) |
| 中文描述： | EC000核心用户手册（SCM68000） |
| 文件页数： | 115/145页 |
| 文件大小： | 829K |
| 代理商： | EC000UM |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页第54页第55页第56页第57页第58页第59页第60页第61页第62页第63页第64页第65页第66页第67页第68页第69页第70页第71页第72页第73页第74页第75页第76页第77页第78页第79页第80页第81页第82页第83页第84页第85页第86页第87页第88页第89页第90页第91页第92页第93页第94页第95页第96页第97页第98页第99页第100页第101页第102页第103页第104页第105页第106页第107页第108页第109页第110页第111页第112页第113页第114页当前第115页第116页第117页第118页第119页第120页第121页第122页第123页第124页第125页第126页第127页第128页第129页第130页第131页第132页第133页第134页第135页第136页第137页第138页第139页第140页第141页第142页第143页第144页第145页
Bus Operation
3-30
EC000 CORE PROCESSOR USER’S MANUAL
MOTOROLA
3.4 BUS ERROR AND HALT OPERATION
In a bus architecture that requires a handshake from an external device, such as the asyn-
chronous bus used in the SCM68000, the handshake may not always occur. A bus error
input is provided to terminate a bus cycle in error when the expected signal is not asserted.
Different systems and different devices within the same system require different maximum
response times. External circuitry can be provided to assert the bus error signal after the
appropriate delay following the assertion of address strobe.
3.4.1 Bus Error Operation
A bus error is recognized when HALTIB is negated and BERRB is asserted, either alone or
with DTACKB.
When the bus error condition is recognized, the current bus cycle is terminated in state 9
(S9) (only BERRB is asserted) or in state 7 (S7) (BERRB and DTACKB are asserted) for a
read cycle or a write cycle. The bus cycle is terminated in state 11 (S11) for the read portion
of a read-modify-write cycle. For the write portion of a read-modify-write cycle, the bus cycle
is terminated in state 21 (S21) (only BERRB is asserted) or in state 19 (S19) (BERRB and
DTACKB are asserted). As long as BERRB remains asserted, the data bus is in the high-
impedance state. Figure 3-25 shows the timing for the normal bus error.
After the aborted bus cycle is terminated and BERRB is negated, the SCM68000 enters ex-
ception processing for the bus error exception. During the exception processing sequence,
the following information is placed on the supervisor stack:
1. Status register
2. Program counter (two words, which may be up to five words past the instruction being
executed)
3. Error information
The first two items are identical to the information stacked by any other exception. The
SCM68000 stacks bus error information to help determine and to correct the error.
After the SCM68000 has placed the required information on the stack, the bus error excep-
tion vector is read from vector table entry 2 (offset $08) and placed in the program counter.
The SCM68000 resumes execution at the address in the vector, which is the first instruction
in the bus error handler routine.
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
..
.
相关PDF资料 |
PDF描述 |
|---|---|
| EC103B | Sensitive SCRs |
| EC103B1 | Sensitive SCRs |
| EC103B2 | Sensitive SCRs |
| EC103B3 | Sensitive SCRs |
| EC103D175 | Thyristor Product Catalog |
相关代理商/技术参数 |
参数描述 |
|---|---|
| EC0010-000 | 制造商:TE Connectivity 功能描述:EC0010-000 |
| EC001031 | 制造商:PHOENIX 制造商全称:PHOENIX CONTACT 功能描述:Header, Nominal current: 12 A, Rated voltage (III/2): 320 V, Assembly: Soldering |
| EC001121 | 制造商:PHOENIX 制造商全称:PHOENIX CONTACT 功能描述:Plug component, Nominal current: 12 A, Rated voltage (III/2): 320 V, Number of positions: 4, Pitch: 5mm, Connection method: Screw connection, Color: Black, Contact surface: Tin |
| EC001283 | 制造商:PHOENIX 制造商全称:PHOENIX CONTACT 功能描述:Plug component, Nominal current: 12 A, Rated voltage (III/2): 320 V, Number of positions: 7, Pitch: 5.08 mm, Connection method: Solder/Slip-on connection, Color: green, Contact surface: Tin, Assembly: Direct mounting |
| EC0013-000 | 制造商:TE Connectivity 功能描述:EC0013-000 |
发布紧急采购，3分钟左右您将得到回复。