參數(shù)資料
型號(hào)： PIC18F4221T-I/ML
廠商： Microchip Technology
文件頁(yè)數(shù)： 75/110頁(yè)
文件大?。?/td> 0K
描述： IC PIC MCU FLASH 2KX16 44QFN
標(biāo)準(zhǔn)包裝： 1,600
系列： PIC® 18F
核心處理器： PIC
芯體尺寸： 8-位
速度： 40MHz
連通性： I²C，SPI，UART/USART
外圍設(shè)備： 欠壓檢測(cè)/復(fù)位，HLVD，POR，PWM，WDT
輸入/輸出數(shù)： 36
程序存儲(chǔ)器容量： 4KB（2K x 16）
程序存儲(chǔ)器類型： 閃存
EEPROM 大小： 256 x 8
RAM 容量： 512 x 8
電壓 - 電源 (Vcc/Vdd)： 4.2 V ~ 5.5 V
數(shù)據(jù)轉(zhuǎn)換器： A/D 13x10b
振蕩器型： 內(nèi)部
工作溫度： -40°C ~ 85°C
封裝/外殼： 44-VQFN 裸露焊盤
包裝： 帶卷 (TR)
2009 Microchip Technology Inc.
DS39689F-page 67
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 6-6:
USE OF THE BANK SELECT REGISTER (DIRECT ADDRESSING)
6.3.2
ACCESS BANK
While the use of the BSR with an embedded 8-bit
address allows users to address the entire range of
data memory, it also means that the user must always
ensure that the correct bank is selected. Otherwise,
data may be read from or written to the wrong location.
This can be disastrous if a GPR is the intended target
of an operation, but an SFR is written to instead.
Verifying and/or changing the BSR for each read or
write to data memory can become very inefficient.
To streamline access for the most commonly used data
memory locations, the data memory is configured with
an Access Bank, which allows users to access a
mapped block of memory without specifying a BSR.
The Access Bank consists of the first 128 bytes of
memory (00h-7Fh) in Bank 0 and the last 128 bytes of
memory (80h-FFh) in Block 15. The lower half is known
as the “Access RAM” and is composed of GPRs. This
upper half is also where the device’s SFRs are
mapped. These two areas are mapped contiguously in
the Access Bank and can be addressed in a linear
fashion by an 8-bit address (Figure 6-5).
The Access Bank is used by core PIC18 instructions
that include the Access RAM bit (the ‘a(chǎn)’ parameter in
the instruction). When ‘a(chǎn)’ is equal to ‘1’, the instruction
uses the BSR and the 8-bit address included in the
opcode for the data memory address. When ‘a(chǎn)’ is ‘0’,
however, the instruction is forced to use the Access
Bank address map; the current value of the BSR is
ignored entirely.
Using this “forced” addressing allows the instruction to
operate on a data address in a single cycle, without
updating the BSR first. For 8-bit addresses of 80h and
above, this means that users can evaluate and operate
on SFRs more efficiently. The Access RAM below 80h
is a good place for data values that the user might need
to access rapidly, such as immediate computational
results or common program variables. Access RAM
also allows for faster and more code efficient context
saving and switching of variables.
The mapping of the Access Bank is slightly different
when the extended instruction set is enabled (XINST
Configuration bit = 1). This is discussed in more detail
6.3.3
GENERAL PURPOSE
REGISTER FILE
PIC18 devices may have banked memory in the GPR
area. This is data RAM which is available for use by all
instructions. GPRs start at the bottom of Bank 0
(address 000h) and grow upwards towards the bottom of
the SFR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other Resets.
Note 1:
The Access RAM bit of the instruction can be used to force an override of the selected bank (BSR<3:0>) to
the registers of the Access Bank.
2:
The MOVFF instruction embeds the entire 12-bit address in the instruction.
Data Memory
Bank Select(2)
7
0
From Opcode(2)
000 0
000h
100h
200h
F00h
FFFh
Bank 0
Bank 1
Bank 15
00h
FFh
00h
FFh
00h
FFh
Bank 2
through
Bank 14
00 0 1
1
1 1 1 1
111
7
0
BSR(1)
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PIC18F4320-E/P 功能描述:8位微控制器 -MCU 8KB 512 RAM 36 I/O 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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
PIC18F4320-E/PT 功能描述:8位微控制器 -MCU 8KB 512 RAM 36 I/O 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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
PIC18F4320-I/ML 功能描述:8位微控制器 -MCU 8KB 512 RAM 36 I/O 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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
PIC18F4320-I/MLG 功能描述:8位微控制器 -MCU 8KB 512 RAM 36 I/O Lead Free Package 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(shí)鐘頻率:50 MHz 程序存儲(chǔ)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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