參數(shù)資料
型號(hào): AM8530H
廠商: Advanced Micro Devices, Inc.
英文描述: Serial Communications Controller
中文描述: 串行通信控制器
文件頁(yè)數(shù): 39/194頁(yè)
文件大?。?/td> 797K
代理商: AM8530H
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)當(dāng)前第39頁(yè)第40頁(yè)第41頁(yè)第42頁(yè)第43頁(yè)第44頁(yè)第45頁(yè)第46頁(yè)第47頁(yè)第48頁(yè)第49頁(yè)第50頁(yè)第51頁(yè)第52頁(yè)第53頁(yè)第54頁(yè)第55頁(yè)第56頁(yè)第57頁(yè)第58頁(yè)第59頁(yè)第60頁(yè)第61頁(yè)第62頁(yè)第63頁(yè)第64頁(yè)第65頁(yè)第66頁(yè)第67頁(yè)第68頁(yè)第69頁(yè)第70頁(yè)第71頁(yè)第72頁(yè)第73頁(yè)第74頁(yè)第75頁(yè)第76頁(yè)第77頁(yè)第78頁(yè)第79頁(yè)第80頁(yè)第81頁(yè)第82頁(yè)第83頁(yè)第84頁(yè)第85頁(yè)第86頁(yè)第87頁(yè)第88頁(yè)第89頁(yè)第90頁(yè)第91頁(yè)第92頁(yè)第93頁(yè)第94頁(yè)第95頁(yè)第96頁(yè)第97頁(yè)第98頁(yè)第99頁(yè)第100頁(yè)第101頁(yè)第102頁(yè)第103頁(yè)第104頁(yè)第105頁(yè)第106頁(yè)第107頁(yè)第108頁(yè)第109頁(yè)第110頁(yè)第111頁(yè)第112頁(yè)第113頁(yè)第114頁(yè)第115頁(yè)第116頁(yè)第117頁(yè)第118頁(yè)第119頁(yè)第120頁(yè)第121頁(yè)第122頁(yè)第123頁(yè)第124頁(yè)第125頁(yè)第126頁(yè)第127頁(yè)第128頁(yè)第129頁(yè)第130頁(yè)第131頁(yè)第132頁(yè)第133頁(yè)第134頁(yè)第135頁(yè)第136頁(yè)第137頁(yè)第138頁(yè)第139頁(yè)第140頁(yè)第141頁(yè)第142頁(yè)第143頁(yè)第144頁(yè)第145頁(yè)第146頁(yè)第147頁(yè)第148頁(yè)第149頁(yè)第150頁(yè)第151頁(yè)第152頁(yè)第153頁(yè)第154頁(yè)第155頁(yè)第156頁(yè)第157頁(yè)第158頁(yè)第159頁(yè)第160頁(yè)第161頁(yè)第162頁(yè)第163頁(yè)第164頁(yè)第165頁(yè)第166頁(yè)第167頁(yè)第168頁(yè)第169頁(yè)第170頁(yè)第171頁(yè)第172頁(yè)第173頁(yè)第174頁(yè)第175頁(yè)第176頁(yè)第177頁(yè)第178頁(yè)第179頁(yè)第180頁(yè)第181頁(yè)第182頁(yè)第183頁(yè)第184頁(yè)第185頁(yè)第186頁(yè)第187頁(yè)第188頁(yè)第189頁(yè)第190頁(yè)第191頁(yè)第192頁(yè)第193頁(yè)第194頁(yè)
I/O Programming Functional Description
AMD
3–8
The interrupt protocol is diagrammed in Figure 3–5. In the quiescent state (i.e. no inter-
rupts pending or under service) each SCC on the daisy chain passes its IEI input through
to its IEO output. An interrupt source that requires servicing requests an interrupt by pull-
ing the INT pin Low if the following conditions exist: 1) interrupt source is enabled (i.e., IE
and MIE bits are set to ‘1’), 2) interrupt source is not already under service (i.e., internal
IUS bit set to ‘0’), 3) no higher priority interrupt is under service (i.e., internal IUS bit set to
‘1’), and 4) an interrupt acknowledge cycle is not currently being executed (i.e.,
INTACK
is High).
When the processor responds with an Interrupt Acknowledge cycle all SCCs that have
enabled interrupt sources with an interrupt pending or already under service, hold their
IEO outputs lines Low. When RD goes Low, only the highest priority SCC with an inter-
rupt pending will have a high IEI input; this is the interrupt being acknowledged, and that
source’s internal IUS bit will be set to ‘1’.
When servicing of the SCC has completed, the Reset Highest IUS Command in WR0
must be issued to unlock the daisy chain, reset the IUS bit, and enable lower-priority in-
terrupt requests.
3.5.2
In this mode,
INTACK
does not have to be generated, and the
INTACK
input pin must be
tied High. This allows a simpler hardware design that does not have to meet the Interrupt
Acknowledge timing (AC timing parameter #38,TdlAi(RD)). Soon after the SCC’s
INT
pin
goes active, an external interrupt controller will jump to the interrupt routine. In the inter-
rupt routine, the code must read RR2 from Channel B to read the vector including status.
When the vector is read from Channel B, it always includes the status regardless of the
VIS bit in WR9 (D0). The status given will decode the highest priority interrupt pending at
the time RR2 is read. Note that the vector is not latched in RR2 so that the next read of
RR2 could produce a different vector if another interrupt occurs; however, accessing RR2
disables it from change during the read operation to prevent an error if a higher interrupt
occurs exactly during the read operation.
Interrupt Without Ac knowledge
Once RR2 is read, the interrupt routine must decode the interrupt pending, and clear the
condition. For example, writing a character to the Transmit Buffer will clear the Transmit
Buffer Empty IP.
Removing the interrupt condition clears the IP bit and deactivates
INT
, but only if there are no other IP bits set.
When the interrupt IP is cleared, RR2
can be read again. This allows the interrupt routine to clear all IPs with one interrupt re-
quest to the processor.
3.5.3
In this mode of operation, the processor must respond to the activation of
INT
by activat-
ing
INTACK
. After enough time has elapsed to allow the daisy chain to settle (AC timing
parameter #38,TdlAi(RD)), the SCC sets the IUS bit for the highest priority IP. If the No
Vector bit in WR9 (D1) is reset to ‘0’, the SCC will then place the interrupt vector on the
data bus during the read strobe.
Interrupt With Ac knowledge With V ec tor
To speed the interrupt response time, the SCC can also modify 3 bits in the vector to indi-
cate status. If it is programmed to include status information in the vector, this status may
be encoded and placed in either bits 1–3 or in bits 4–6 as programmed by the Status
High/Status Low bit in WR9. To include status, the VIS bit in WR9 (D0) must be set to ‘1’.
The service routine must then clear the interrupting condition. For example, writing a
character to the Transmit Buffer will clear the Transmit Buffer empty IP. After the inter-
rupting condition is cleared, the routine can read RR3 to determine if any other IP bits are
set and clear them. At the end of the interrupt routine, a Reset IUS command must then
be issued via WR0 to unlock the daisy chain and enable lower-priority interrupt requests.
This is the only way, short of a software or hardware reset, that an IUS bit may be reset.
相關(guān)PDF資料
PDF描述
AM85C30-10PC Enhanced Serial Communications Controller
Am85C30 Serial Communications Controller
AM85C30 Enhanced Serial Communications Controller
AM85C30-8PC Enhanced Serial Communications Controller
AM85C30-16JC Enhanced Serial Communications Controller
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AM8530H/AM85C301992 制造商:AMD 制造商全稱(chēng):Advanced Micro Devices 功能描述:Am8530H/Am85C30 1992 - Am8530H/Am85C30 Serial Communications Controller
AM8530H-4DC 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:Communications Controller
AM8530H-4DCB 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:Communications Controller
AM8530H-4JC 制造商:未知廠家 制造商全稱(chēng):未知廠家 功能描述:Communications Controller