 |
数据搜索系统，热门电子元器件搜索 |
|
|
数据搜索系统，热门电子元器件搜索 |
|
71M6521FE-IM/F 数据表(PDF) 70 Page - Maxim Integrated Products |
|
|
|||||||||||||||||||||||||||||
71M6521FE-IM/F 数据表(HTML) 70 Page - Maxim Integrated Products |
|
|
70 / 107 page  71M6521DE/DH/FE Data Sheet Page: 70 of 107 Rev 2 Optical Interface The pins OPT_TX and OPT_RX can be used for a regular serial interface, e.g. by connecting a RS_232 transceiver, or they can be used to directly operate optical components, e.g. an infrared diode and phototransistor implementing a FLAG interface. Figure 38 shows the basic connections. The OPT_TX pin becomes active when the I/O RAM register OPT_TXDIS is set to 0. The polarity of the OPT_TX and OPT_RX pins can be inverted with configuration bits OPT_TXINV and OPT_RXINV, respectively. The OPT_TX output may be modulated at 38kHz when system power is present. Modulation is not available in BROWNOUT mode. The OPT_TXMOD bit enables modulation. The duty cycle is controlled by OPT_FDC[1:0], which can select 50%, 25%, 12.5%, and 6.25% duty cycle. A 6.25% duty cycle means OPT_TX is low for 6.25% of the period. The receive pin (OPT_RX) may need an analog filter when receiving modulated optical signals. With modulation, an optical emitter can be operated at higher current than nominal, enabling it to increase the distance along the optical path. If operation in BROWNOUT mode is desired, the external components should be connected to V3P3D. Figure 38: Connection for Optical Components Connecting V1 and Reset Pins A voltage divider should be used to establish that V1 is in a safe range when the meter is in mission mode (V1 must be lower than 2.9V in all cases in order to keep the hardware watchdog timer enabled). For proper debugging or loading code into the 71M6521DE/DH/FE mounted on a PCB, it is necessary to have a provision like the header shown above R1 in Figure 39. A shorting jumper on this header pulls V1 up to V3P3 disabling the hardware watchdog timer. The parallel impedance of R1 and R2 should be approximately 20 to 30k Ω in order to provide hysteresis for the power fault monitor. Figure 39: Voltage Divider for V1 OPT_TX R 2 R 1 OPT_RX 71M6521 V3P3SYS Phototransistor LED 100k Ω 100pF V3P3SYS OPT_TX R 2 R 1 OPT_RX 71M6521 V3P3SYS Phototransistor LED 100k Ω 100pF V3P3SYS V3P3 R 2 V1 R 1 R 3 5k Ω C 1 100pF GND V3P3 R 2 V1 R 1 R 3 5k Ω C 1 100pF GND |
|
链接网址 |
| ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 数据表链接 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
| Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
|
Family Site : ic2ic.com |
icmetro.com |
Chinese ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
