Normally the prescaler is set to divide PCLK" />
參數(shù)資料
型號(hào): 668-0003-C
廠商: Rabbit Semiconductor
文件頁(yè)數(shù): 28/228頁(yè)
文件大?。?/td> 0K
描述: IC CPU RABBIT2000 30MHZ 100PQFP
標(biāo)準(zhǔn)包裝: 100
系列: Rabbit 2000
處理器類型: Rabbit 2000 8-位
速度: 30MHz
電壓: 2.7V,3V,3.3V,5V
安裝類型: 表面貼裝
封裝/外殼: 100-BQFP
供應(yīng)商設(shè)備封裝: 100-PQFP(14x20)
包裝: 托盤(pán)
其它名稱: 316-1004
668-0003
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)當(dāng)前第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)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)第195頁(yè)第196頁(yè)第197頁(yè)第198頁(yè)第199頁(yè)第200頁(yè)第201頁(yè)第202頁(yè)第203頁(yè)第204頁(yè)第205頁(yè)第206頁(yè)第207頁(yè)第208頁(yè)第209頁(yè)第210頁(yè)第211頁(yè)第212頁(yè)第213頁(yè)第214頁(yè)第215頁(yè)第216頁(yè)第217頁(yè)第218頁(yè)第219頁(yè)第220頁(yè)第221頁(yè)第222頁(yè)第223頁(yè)第224頁(yè)第225頁(yè)第226頁(yè)第227頁(yè)第228頁(yè)
117
11.2.1 Using Timer B
Normally the prescaler is set to divide PCLK/2 by a number that provides a counting rate
appropriate to the problem. For example, if the clock is 22.1184 MHz, then PCLK/2 is
11.0592 MHz. A Timer B clock rate of 11.0592 MHz will cause a complete cycle of the
10-bit clock in 92.6 s.
Normally an interrupt will occur when either of the comparators in Timer B generates a
pulse. The interrupt routine must detect which comparator is responsible for the interrupt
and dispatch the interrupt to a service routine. The service routine sets up the next match
value, which will become the match value after the next interrupt. If the clocked parallel
ports are being used, then a value will normally be loaded into some bits of the parallel
port register. These bits will become the output bits on the next match pulse. (It is neces-
sary to keep a shadow register for the parallel port unless the bit-addressable feature of
ports D and E is used.)
If it is desired to read the time from the Timer B counter, either during an interrupt caused
by the match pulse or in some other interrupt routine asynchronous to the match pulse, a
special procedure needs to be used to read the counter because the upper 2 bits are in a dif-
ferent register than the lower 8 bits. The following method is suggested.
1. Read the lower 8 bits.
2. Read the upper 2 bits
3. Read the lower 8 bits again
4. If bit 7 changed from 1 to 0 between the first and second read of the lower 8 bits there
has been a carry to the upper 2 bits. In this case read the upper 2 bits again and decre-
ment those 2 bits to get the correct upper 2 bits. Use the first read of the lower 8 bits.
This procedure assumes that the time between reads can be guaranteed to be less than 256
counts. This can be guaranteed in most systems by disabling the priority 1 interrupts,
which will normally be disabled in any case in an interrupt routine.
It is inadvisable to disable the high-priority interrupts (levels 2 and 3) as that defeats their
purpose.
If speed is critical, the three reads of the registers can be performed without testing for the
carry. The three register values can be saved and the carry test can be performed by a
lower priority analysis routine. Since the upper 2 bits are in the register TBCMR at
address 0x0BE, and the lower 8 bits are in TBCLR at address 0x0BF, both registers can be
read with a single 16-bit I/O instruction. The following sequence illustrates how the regis-
ters could be captured.
; enter from external interrupt on pulse input transition
; 19 clocks latency plus 10 clocks interrupt execution
push af
; 7
push hl
ioi ld a,(TBCLR)
; 11 get lower 8 bits of counter
ioi ld hl,(TBCMR) ; 13 get l=upper, h=lower
相關(guān)PDF資料
PDF描述
668-0011 IC MPU RABIT3000A 55.5MHZ128LQFP
6PAIC3106IRGZRQ1 IC AUDIO CODEC STEREO 48-QFN
70001851 DEVICE SERVER 1PORT SRL-ETHERNET
73M1822-IM/F MICRODAA VOICE DATA/FAX 42-QFN
73M1866B-IM/F MICRODAA SGL PCM HIGHWAY 42-QFN
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
6680005578829 制造商: 功能描述: 制造商:undefined 功能描述:
6680008268807 制造商: 功能描述: 制造商:undefined 功能描述:
6680-00-882-0965 制造商: 功能描述: 制造商:undefined 功能描述:
6680008912796 制造商: 功能描述: 制造商:undefined 功能描述:
6680009296667 制造商: 功能描述: 制造商:undefined 功能描述: