參數(shù)資料
型號: 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
文件頁數(shù): 107/194頁
文件大?。?/td> 797K
代理商: AM8530H
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁第52頁第53頁第54頁第55頁第56頁第57頁第58頁第59頁第60頁第61頁第62頁第63頁第64頁第65頁第66頁第67頁第68頁第69頁第70頁第71頁第72頁第73頁第74頁第75頁第76頁第77頁第78頁第79頁第80頁第81頁第82頁第83頁第84頁第85頁第86頁第87頁第88頁第89頁第90頁第91頁第92頁第93頁第94頁第95頁第96頁第97頁第98頁第99頁第100頁第101頁第102頁第103頁第104頁第105頁第106頁當(dāng)前第107頁第108頁第109頁第110頁第111頁第112頁第113頁第114頁第115頁第116頁第117頁第118頁第119頁第120頁第121頁第122頁第123頁第124頁第125頁第126頁第127頁第128頁第129頁第130頁第131頁第132頁第133頁第134頁第135頁第136頁第137頁第138頁第139頁第140頁第141頁第142頁第143頁第144頁第145頁第146頁第147頁第148頁第149頁第150頁第151頁第152頁第153頁第154頁第155頁第156頁第157頁第158頁第159頁第160頁第161頁第162頁第163頁第164頁第165頁第166頁第167頁第168頁第169頁第170頁第171頁第172頁第173頁第174頁第175頁第176頁第177頁第178頁第179頁第180頁第181頁第182頁第183頁第184頁第185頁第186頁第187頁第188頁第189頁第190頁第191頁第192頁第193頁第194頁
Support Circuitry Programming
AMD
5–13
However, if the transition marking a bit cell boundary occurs between the middle of count
16 and the middle of count 19 the DPLL is sampling the data too early in the bit cell. In
response to this the DPLL extends its count by one during the next 0 to 31 counting cycle,
which effectively moves the receive clock edges closer to to where they should be. In FM
mode any transitions occurring between the middle of count 19 in one cycle and the mid-
dle of count 12 during the next cycle are ignored by the DPLL. This is necessary to guar-
antee that any data transitions in the bit cells will not cause an adjustment to the counting
cycle.
As in NRZI mode, if an adjustment to the counting cycle is necessary, the DPLL modifies
count 5, either deleting it or doubling it. If no adjustment is necessary, the count sequence
proceeds normally. While the DPLL is in Search mode, the counter remains at count 16,
where the receive output is Low and the transmit output is Low. This fact can be used to
provide a transmit clock under software control since the DPLL is in Search mode while it
is disabled. Note that while the DPLL is disabled the transmit clock output of the DPLL
may be toggled by alternately selecting FM and NRZI mode in the DPLL. The same is
true of the receive clock.
+1
–1
+1
–1
+1
–1
+1
–1
+1
–1
+1
–1
+1
–1
+1
–1
+1
32
32
32
31
31
31
33
33
33
Receive
Data
DPLL
Output
Correction
Windows
Count
Length
Figure 5–7. DPLL in FM Mode
5.5.3.3
In addition to FM and NRZI encoded data, the DPLL may also be used to recover the
clock from Manchester encoded data, which contains a transition at the center of every bit
cell. Here it is the direction of the transition that distinguishes a ‘1’ from a ‘0’. Another
way of looking at Manchester encoding is to realize that, during the first half of the bit cell
the data are sent; during the second half of the bit cell the complement of the data are
sent. This is shown in Figure 5–9, along with the DPLL output if it thinks that the mid-bit
transitions are really bit cell boundaries. As is obvious from the figure, if the receiver sam-
ples the data on the falling edge of the DPLL receive clock output, the Manchester data
will be properly decoded. This occurs if the receiver is programmed to accept NRZ data.
Manc hester Dec oding Mode
5.5.3.4
From the above discussion together with an examination of FM0 and FM1 data encoding,
it should be obvious that only clock transitions should exist on the receive data pin when
the DPLL is programmed to enter Search mode. If this is not the case the DPLL may at-
tempt to lock on to the data transitions. With FM0 encoding this requires continuous ‘1’s
received when leaving Search mode. In FM1 encoding it is continuous ‘0’s; with
Manchester encoded data this means alternating ‘1’s and ‘0’s.
FM Mode DPLL Rec eive S tatus
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: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:未知廠家 功能描述:Communications Controller
AM8530H-4DCB 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Communications Controller
AM8530H-4JC 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Communications Controller