參數(shù)資料
型號: COP8SGH944M9
廠商: National Semiconductor Corporation
英文描述: 8-Bit CMOS ROM Based and OTP Microcontrollers with 8k to 32k Memory, Two Comparators and USART
中文描述: 8位的CMOS基于ROM和OTP微控制器具有8K到32K的內(nèi)存,2個比較器和USART
文件頁數(shù): 25/62頁
文件大?。?/td> 913K
代理商: COP8SGH944M9
8.0 USART (Continued)
8.6 USART INTERRUPTS
The USART is capable of generating interrupts. Interrupts
are generated on Receive Buffer Full and Transmit Buffer
Empty. Both interrupts have individual interrupt vectors. Two
bytes of program memory space are reserved for each in-
terrupt vector. The two vectors are located at addresses
0xEC to 0xEF Hex in the program memory space. The
interrupts can be individually enabled or disabled using En-
able Transmit Interrupt (ETI) and Enable Receive Interrupt
(ERI) bits in the ENUI register.
The interrupt from the Transmitter is set pending, and re-
mains pending, as long as both the TBMT and ETI bits are
set. To remove this interrupt, software must either clear the
ETI bit or write to the TBUF register (thus clearing the TBMT
bit).
The interrupt from the receiver is set pending, and remains
pending, as long as both the RBFL and ERI bits are set. To
remove this interrupt, software must either clear the ERI bit
or read from the RBUF register (thus clearing the RBFL bit).
8.7 Baud Clock Generation
The clock inputs to the transmitter and receiver sections of
the USART can be individually selected to come either from
an external source at the CKX pin (port L, pin L1) or from a
source selected in the PSR and BAUD registers. Internally,
the basic baud clock is created from the oscillator frequency
through a two-stage divider chain consisting of a 1–16 (in-
crements of 0.5) prescaler and an 11-bit binary counter.
Figure 23). The divide factors are specified through two
read/write registers shown in
Figure 24. Note that the 11-bit
Baud Rate Divisor spills over into the Prescaler Select Reg-
ister (PSR). PSR is cleared upon reset.
As shown in
Table 5, a Prescaler Factor of 0 corresponds to
NO CLOCK. This condition is the USART power down mode
where the USART clock is turned off for power saving pur-
pose. The user must also turn the USART clock off when a
different baud rate is chosen.
The correspondences between the 5-bit Prescaler Select
and Prescaler factors are shown in
Table 5. There are many
ways to calculate the two divisor factors, but one particularly
effective method would be to achieve a 1.8432 MHz fre-
quency coming out of the first stage. The 1.8432 MHz pres-
caler output is then used to drive the software programmable
baud rate counter to create a 16x clock for the following baud
rates: 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 3600,
4800, 7200, 9600, 19200 and 38400 (
Table 4). Other baud
10131740
FIGURE 22. Framing Formats
COP8SG
Family
www.national.com
31
相關(guān)PDF資料
PDF描述
COP8SGH944N3 LP38859 3A Fast-Response High-Accuracy LDO Linear Regulator with Soft-Start; Package: TO-263; No of Pins: 5
COP8SGR940M7 LP3995 Micropower 150mA CMOS Voltage Regulator with Active Shutdown; Package: MICRO SMD; No of Pins: 5
COP8SGR940M8 LP3995 Micropower 150mA CMOS Voltage Regulator with Active Shutdown; Package: MICRO SMD; No of Pins: 5
COP8SGR940M9 LP3995 Micropower 150mA CMOS Voltage Regulator with Active Shutdown; Package: MICRO SMD; No of Pins: 5
COP8SGR940N3 LP3995 Micropower 150mA CMOS Voltage Regulator with Active Shutdown; Package: MICRO SMD; No of Pins: 5
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
COP8SGR728M7 功能描述:8位微控制器 -MCU 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
COP8SGR728M7/NOPB 功能描述:8位微控制器 -MCU 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
COP8SGR728M8 功能描述:8位微控制器 -MCU 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
COP8SGR728M8/NOPB 功能描述:8位微控制器 -MCU 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
COP8SGR728N8 功能描述:8位微控制器 -MCU 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