參數(shù)資料
型號： AT87C51RB2-SLSUL
廠商： Atmel
文件頁數(shù)： 58/84頁
文件大?。?/td> 0K
描述： IC 8051 MCU 16K OTP 30MHZ 44PLCC
標(biāo)準(zhǔn)包裝： 972
系列： 87C
核心處理器： 8051
芯體尺寸： 8-位
速度： 30/20MHz
連通性： UART/USART
外圍設(shè)備： POR，PWM，WDT
輸入/輸出數(shù)： 32
程序存儲器容量： 16KB（16K x 8）
程序存儲器類型： OTP
RAM 容量： 512 x 8
電壓 - 電源 (Vcc/Vdd)： 2.7 V ~ 5.5 V
振蕩器型： 內(nèi)部
工作溫度： -40°C ~ 85°C
封裝/外殼： 44-LCC（J 形引線）
包裝： 管件
2007-2012 Microchip Technology Inc.
DS70292G-page 63
dsPIC33FJ32GP302/304, dsPIC33FJ64GPX02/X04, AND dsPIC33FJ128GPX02/X04
4.6
Modulo Addressing
Modulo Addressing mode is a method of providing an
automated means to support circular data buffers using
hardware. The objective is to remove the need for
software to perform data address boundary checks
when executing tightly looped code, as is typical in
many DSP algorithms.
Modulo Addressing can operate in either data or program
space (since the data pointer mechanism is essentially
the same for both). One circular buffer can be supported
in each of the X (which also provides the pointers into
program space) and Y data spaces. Modulo Addressing
can operate on any W register pointer. However, it is not
advisable to use W14 or W15 for Modulo Addressing
since these two registers are used as the Stack Frame
Pointer and Stack Pointer, respectively.
In general, any particular circular buffer can be config-
ured to operate in only one direction as there are
certain restrictions on the buffer start address (for incre-
menting buffers), or end address (for decrementing
buffers), based upon the direction of the buffer.
The only exception to the usage restrictions is for
buffers that have a power-of-two length. As these
buffers satisfy the start and end address criteria, they
can operate in a bidirectional mode (that is, address
boundary checks are performed on both the lower and
upper address boundaries).
4.6.1
START AND END ADDRESS
The Modulo Addressing scheme requires that a
starting and ending address be specified and loaded
into the 16-bit Modulo Buffer Address registers:
XMODSRT, XMODEND, YMODSRT and YMODEND
(see Table 4-1).
The length of a circular buffer is not directly specified. It
is determined by the difference between the
corresponding start and end addresses. The maximum
possible length of the circular buffer is 32K words
(64 Kbytes).
4.6.2
W ADDRESS REGISTER
SELECTION
The Modulo and Bit-Reversed Addressing Control
register, MODCON<15:0>, contains enable flags as well
as a W register field to specify the W Address registers.
The XWM and YWM fields select the registers that
operate with Modulo Addressing:
If XWM = 15, X RAGU and X WAGU Modulo
Addressing is disabled.
If YWM = 15, Y AGU Modulo Addressing is
disabled.
The X Address Space Pointer W register (XWM), to
which Modulo Addressing is to be applied, is stored in
MODCON<3:0> (see Table 4-1). Modulo Addressing is
enabled for X data space when XWM is set to any value
other than ‘15’ and the XMODEN bit is set at
MODCON<15>.
The Y Address Space Pointer W register (YWM) to
which Modulo Addressing is to be applied is stored in
MODCON<7:4>. Modulo Addressing is enabled for Y
data space when YWM is set to any value other than
‘15’ and the YMODEN bit is set at MODCON<14>.
FIGURE 4-7:
MODULO ADDRESSING OPERATION EXAMPLE
Note:
Y
space
Modulo
Addressing
EA
calculations assume word-sized data (LSb
of every EA is always clear).
0x1100
0x1163
Start Addr = 0x1100
End Addr = 0x1163
Length = 0x0032 words
Byte
Address
MOV
#0x1100, W0
MOV
W0, XMODSRT
;set modulo start address
MOV
#0x1163, W0
MOV
W0, MODEND
;set modulo end address
MOV
#0x8001, W0
MOV
W0, MODCON
;enable W1, X AGU for modulo
MOV
#0x0000, W0
;W0 holds buffer fill value
MOV
#0x1110, W1
;point W1 to buffer
DO
AGAIN, #0x31
;fill the 50 buffer locations
MOV
W0, [W1++]
;fill the next location
AGAIN: INC W0, W0
;increment the fill value
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AT87C51RB2-SLSUM 功能描述:8位微控制器 -MCU OTP RB/16K 40MHZ 3V RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT87C51RC2 制造商:IRF 制造商全稱:International Rectifier 功能描述:High Performance 8-bit Microcontroller
AT87C51RC2-3CSUL 功能描述:8位微控制器 -MCU OTP RC/32K 40MHZ 3V RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT87C51RC2-3CSUM 功能描述:8位微控制器 -MCU 32KB SCMOS 3/2 .5 OTP RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
AT87C51RC2-RLTUL 功能描述:8位微控制器 -MCU OTP RC/32K 40MHZ 3V RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時鐘頻率:50 MHz 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
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