To provide a convenient means of attaching two grounds to the serial cable, there are several pins (labeled GND) on the communications connector that are connected to the controller’s ground plane. You can use the QScreen’s RS485 link to create such a multi-drop serial network. The SPI can transfer data much more rapidly than an asynchronous serial link - its maximum rate is 2 Megabits/second. SPIE is a local interrupt mask that allows an interrupt to be recognized when an SPI data transfer has completed, or if a write collision or mode fault is detected. When this bit is high, the transceiver is in transmit mode. InitRS485() configures Port D to ensure that bit 5 is an output. Regardless of the network, however, there are only four signals used: SCK provides a synchronized clock, MOSI and MISO signals are used for data transmission and reception, and /SS configures the QScreen as a master or slave device. From the QScreen Controller’s point of view, these three signals (TxD, RxD, and ground) are the only connections required to perform serial communications. If your computer does not have an RS-232 serial port, low cost USB-to-RS-232 serial cables are available; contact Mosaic Industries for details.
Rs485 cables not only vary in the structure of the core but also in the number of twisted pairs. 04), a TPS2L(G2) preloaded with the BP-Tester-UI app, and the necessary cables. The master and slave can then exchange data. For example, at 4800 baud (bits per second), each bit lasts about 200 microseconds (µs), and if communications are full duplex (e.g., if the QScreen Controller echoes each incoming character), then there is a serial interrupt every 100 µs or so. The default serial routines used by the onboard kernel assume that full duplex communications are available, so you cannot use the RS485 protocol to program the controller. The standard C serial I/O routines such as printf(), scanf(), putchar(), and getchar() give you high level access to the serial ports. The Control-C Glossary contains a list of functions that temporarily disable interrupts, and the glossary entries give further information regarding how long interrupts are disabled.
Rather, rs485 cable it relies on software handshaking via transmission of XON/XOFF characters to coordinate data transfer and ensure that information is not lost when one of the communicating parties is busy. These steps greatly reduce the chance that the communicating devices might be damaged by contention on the SPI bus. While these signals provide a data path, they do not provide hardware handshaking that allows the two communicating parties to let each other know when they are ready to send or receive data. A hardware reset (pressing down on the reset switch) has the same effect. Board lengthened at the power connector end for additional screw down holes. At the end of a received character, the service routine takes about 45 µs. Moreover, if Serial2 is running full duplex at 4800 baud, any other interrupt service routine that takes longer than 100 µs is likely to cause a problem. Thus, as a rough approximation, operating at 4800 baud full duplex requires about 40 to 50% of the 6811's CPU time (that is, an average of approximately 40 to 50 µs service time every 100 µs). All in all, RS485 really allowed full automation possible with its ability to connect so many devices at once.
RS485 can handle up to 32 connected devices. It seems if there is a lot of RFI in the installation, shielded twisted cable can be justified. Table 9-6 shows the connection diagram for a standard 9-pin serial cable. The secondary serial port is connected similarly except that the onboard connection of RTS to CTS, and DSR to DTR are permanent. For those of you interested in the details, here’s how it works: The low-level serial driver routines named Key(), AskKey() and Emit() are revectorable routines that can be redirected to use either of the serial ports. The Serial2 channel is always configured for RS232 communications, and can sustain baud rates up to 4800 baud. Now select the "Comm" item in the "Settings" menu of the Terminal program, and click on 1200 baud (or whatever baud rate you selected in the command above). If you have already downloaded the program, you are ready to go.
A Ciência & Ensino é uma publicação semestral destinada a professores de ciências do ensino fundamental e médio e seus formadores.
Cross Roads Electronics
por Lucille Bosley (2024-06-27)
To provide a convenient means of attaching two grounds to the serial cable, there are several pins (labeled GND) on the communications connector that are connected to the controller’s ground plane. You can use the QScreen’s RS485 link to create such a multi-drop serial network. The SPI can transfer data much more rapidly than an asynchronous serial link - its maximum rate is 2 Megabits/second. SPIE is a local interrupt mask that allows an interrupt to be recognized when an SPI data transfer has completed, or if a write collision or mode fault is detected. When this bit is high, the transceiver is in transmit mode. InitRS485() configures Port D to ensure that bit 5 is an output. Regardless of the network, however, there are only four signals used: SCK provides a synchronized clock, MOSI and MISO signals are used for data transmission and reception, and /SS configures the QScreen as a master or slave device. From the QScreen Controller’s point of view, these three signals (TxD, RxD, and ground) are the only connections required to perform serial communications. If your computer does not have an RS-232 serial port, low cost USB-to-RS-232 serial cables are available; contact Mosaic Industries for details.
Rs485 cables not only vary in the structure of the core but also in the number of twisted pairs. 04), a TPS2L(G2) preloaded with the BP-Tester-UI app, and the necessary cables. The master and slave can then exchange data. For example, at 4800 baud (bits per second), each bit lasts about 200 microseconds (µs), and if communications are full duplex (e.g., if the QScreen Controller echoes each incoming character), then there is a serial interrupt every 100 µs or so. The default serial routines used by the onboard kernel assume that full duplex communications are available, so you cannot use the RS485 protocol to program the controller. The standard C serial I/O routines such as printf(), scanf(), putchar(), and getchar() give you high level access to the serial ports. The Control-C Glossary contains a list of functions that temporarily disable interrupts, and the glossary entries give further information regarding how long interrupts are disabled.
Rather, rs485 cable it relies on software handshaking via transmission of XON/XOFF characters to coordinate data transfer and ensure that information is not lost when one of the communicating parties is busy. These steps greatly reduce the chance that the communicating devices might be damaged by contention on the SPI bus. While these signals provide a data path, they do not provide hardware handshaking that allows the two communicating parties to let each other know when they are ready to send or receive data. A hardware reset (pressing down on the reset switch) has the same effect. Board lengthened at the power connector end for additional screw down holes. At the end of a received character, the service routine takes about 45 µs. Moreover, if Serial2 is running full duplex at 4800 baud, any other interrupt service routine that takes longer than 100 µs is likely to cause a problem. Thus, as a rough approximation, operating at 4800 baud full duplex requires about 40 to 50% of the 6811's CPU time (that is, an average of approximately 40 to 50 µs service time every 100 µs). All in all, RS485 really allowed full automation possible with its ability to connect so many devices at once.
RS485 can handle up to 32 connected devices. It seems if there is a lot of RFI in the installation, shielded twisted cable can be justified. Table 9-6 shows the connection diagram for a standard 9-pin serial cable. The secondary serial port is connected similarly except that the onboard connection of RTS to CTS, and DSR to DTR are permanent. For those of you interested in the details, here’s how it works: The low-level serial driver routines named Key(), AskKey() and Emit() are revectorable routines that can be redirected to use either of the serial ports. The Serial2 channel is always configured for RS232 communications, and can sustain baud rates up to 4800 baud. Now select the "Comm" item in the "Settings" menu of the Terminal program, and click on 1200 baud (or whatever baud rate you selected in the command above). If you have already downloaded the program, you are ready to go.