參數(shù)資料
型號(hào): AT89S8252-24AC
廠商: Atmel
文件頁(yè)數(shù): 5/41頁(yè)
文件大小: 0K
描述: MCU W/SPI 8KB FLSH 2K EEP 44TQFP
標(biāo)準(zhǔn)包裝: 160
系列: 89S
核心處理器: 8051
芯體尺寸: 8-位
速度: 24MHz
連通性: SPI,UART/USART
外圍設(shè)備: POR,WDT
輸入/輸出數(shù): 32
程序存儲(chǔ)器容量: 8KB(8K x 8)
程序存儲(chǔ)器類型: 閃存
EEPROM 大小: 2K x 8
RAM 容量: 256 x 8
電壓 - 電源 (Vcc/Vdd): 4 V ~ 6 V
振蕩器型: 內(nèi)部
工作溫度: 0°C ~ 70°C
封裝/外殼: 44-TQFP
包裝: 托盤
其它名稱: AT89S825224AC
13
AT89S8252
0401G–MICRO–3/06
Auto-reload (Up or Down
Counter)
Timer 2 can be programmed to count up or down when configured in its 16-bit auto-
reload mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in
the SFR T2MOD (see Table 9). Upon reset, the DCEN bit is set to 0 so that timer 2 will
default to count up. When DCEN is set, Timer 2 can count up or down, depending on the
value of the T2EX pin.
Figure 2 shows Timer 2 automatically counting up when DCEN = 0. In this mode, two
options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to
0FFFFH and then sets the TF2 bit upon overflow. The overflow also causes the timer
registers to be reloaded with the 16-bit value in RCAP2H and RCAP2L. The values in
RCAP2H and RCAP2L are preset by software. If EXEN2 = 1, a 16-bit reload can be trig-
gered either by an overflow or by a 1-to-0 transition at external input T2EX. This
transition also sets the EXF2 bit. Both the TF2 and EXF2 bits can generate an interrupt
if enabled.
Setting the DCEN bit enables Timer 2 to count up or down, as shown in Figure 3. In this
mode, the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer 2
count up. The timer will overflow at 0FFFFH and set the TF2 bit. This overflow also
causes the 16-bit value in RCAP2H and RCAP2L to be reloaded into the timer registers,
TH2 and TL2, respectively.
A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2 and TL2
equal the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and
causes 0FFFFH to be reloaded into the timer registers.
The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a
17th bit of resolution. In this operating mode, EXF2 does not flag an interrupt.
Figure 2. Timer 2 in Auto Reload Mode (DCEN = 0)
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參數(shù)描述
AT89S8252-24AI 功能描述:8位微控制器 -MCU w/8k 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
AT89S8252-24AU 制造商:Rochester Electronics LLC 功能描述:
AT89S8252-24JC 功能描述:8位微控制器 -MCU 8K Flash 24M 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
AT89S8252-24JI 功能描述:8位微控制器 -MCU 8K Flash 24M 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
AT89S8252-24PC 功能描述:8位微控制器 -MCU 8K Flash 24M 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