Datasheet DS1801 (Analog Devices) - 3
| Hersteller | Analog Devices |
| Beschreibung | Dual Audio Taper Potentiometer |
| Seiten / Seite | 10 / 3 — 3-WIRE SERIAL INTERFACE CONTROL. 16-BIT I/O SHIFT REGISTER |
| Dateiformat / Größe | PDF / 235 Kb |
| Dokumentensprache | Englisch |
3-WIRE SERIAL INTERFACE CONTROL. 16-BIT I/O SHIFT REGISTER
Modelllinie für dieses Datenblatt
Textversion des Dokuments
DS1801
3-WIRE SERIAL INTERFACE CONTROL
Communication and control of the DS1801 is accomplished through a 3-wire serial port interface that drives an internal control logic unit. The 3-wire serial interface is designed for microprocessor or microcontroller applications. The interface consists of three input signals which include RST , CLK and D. The RST control signal is used to enable 3-wire serial port write operations. The CLK terminal is a clock signal input that provides synchronization for data I/O while the D signal input serves to transfer potentiometer wiper position settings to the device. As shown in Figure 3, a 3-wire serial port operation begins with a transition of the RST signal input to a high state. Once the 3-wire port has been activated, data is clocked into the part on the low to high transition of the CLK signal input. Data input via the D line is transferred in the order of the desired potentiometer-0 value followed by the potentiometer-1 value. The DS1801 contains two 65-position potentiometers whose wiper positions are set by an 8-bit value. These two 8-bit values are written to the 16-bit I/O shift register which is used to store wiper position during powered conditions. Because the potentiometer has 65-positions, only 7 bits of data are needed to set wiper position. A detailed diagram of the 16-bit I/O shift register is shown in Figure 2. Bits 0 through 7 are reserved for the potentiometer-0 control while bits 8 through 15 are reserved for control of potentiometer-1. Bits 0 through 5 are used for actual wiper positioning of potentiometer-0. Bit 6 is used to mute potentiometer-0. If this bit has value 1, the potentiometer-0 wiper will be connected to the low end of the resistive array the mute position. The value of bit 7 is a “don’t care” and will not affect operation of the DS1801 or potentiometer-0. Bits 8 through 13 are used for wiper positioning of potentiometer-1. Bit 14 is used for muting of the potentiometer-1 wiper output. Bit 15, like bit 7, is a “don’t care” and will not affect operation of the DS1801. Data for the DS1801 is transmitted LSB first starting with bit 0. A complete transmission of 16 bits of data is required to insure proper setting of each potentiometer’s wiper. An incomplete transmission may result in undesired wiper settings. Once the complete 16 bits of information has been transmitted and the RST signal input transitions to a low state, the new wiper positions are loaded into the part.
16-BIT I/O SHIFT REGISTER
Figure 2 3 of 10
3-WIRE SERIAL INTERFACE CONTROL
Communication and control of the DS1801 is accomplished through a 3-wire serial port interface that drives an internal control logic unit. The 3-wire serial interface is designed for microprocessor or microcontroller applications. The interface consists of three input signals which include RST , CLK and D. The RST control signal is used to enable 3-wire serial port write operations. The CLK terminal is a clock signal input that provides synchronization for data I/O while the D signal input serves to transfer potentiometer wiper position settings to the device. As shown in Figure 3, a 3-wire serial port operation begins with a transition of the RST signal input to a high state. Once the 3-wire port has been activated, data is clocked into the part on the low to high transition of the CLK signal input. Data input via the D line is transferred in the order of the desired potentiometer-0 value followed by the potentiometer-1 value. The DS1801 contains two 65-position potentiometers whose wiper positions are set by an 8-bit value. These two 8-bit values are written to the 16-bit I/O shift register which is used to store wiper position during powered conditions. Because the potentiometer has 65-positions, only 7 bits of data are needed to set wiper position. A detailed diagram of the 16-bit I/O shift register is shown in Figure 2. Bits 0 through 7 are reserved for the potentiometer-0 control while bits 8 through 15 are reserved for control of potentiometer-1. Bits 0 through 5 are used for actual wiper positioning of potentiometer-0. Bit 6 is used to mute potentiometer-0. If this bit has value 1, the potentiometer-0 wiper will be connected to the low end of the resistive array the mute position. The value of bit 7 is a “don’t care” and will not affect operation of the DS1801 or potentiometer-0. Bits 8 through 13 are used for wiper positioning of potentiometer-1. Bit 14 is used for muting of the potentiometer-1 wiper output. Bit 15, like bit 7, is a “don’t care” and will not affect operation of the DS1801. Data for the DS1801 is transmitted LSB first starting with bit 0. A complete transmission of 16 bits of data is required to insure proper setting of each potentiometer’s wiper. An incomplete transmission may result in undesired wiper settings. Once the complete 16 bits of information has been transmitted and the RST signal input transitions to a low state, the new wiper positions are loaded into the part.
16-BIT I/O SHIFT REGISTER
Figure 2 3 of 10