Features

Two linear cone digital programmable potentiometers

Each potential calculates 64 resistance connections

end resistance 2.5 k , 10 k , 50 k or 100 k

Potching control and memory access through the I2C interface

Low wipers resistance, usually 80 #8222; Non -easy loss memory, each potential meter can set up to four wiper

When power -on, automatically call the saved wiper settings

2.5 to 6.0 volt operations

[

[ 123] The current waiting current is less than 1 μA

1000,000 non -easy -to -sex writing cycles

100 years of non -loss -loss memory data reserved

20 lead Soic and tssop packaging [123 123 ]

Industrial temperature range

Instructions

cat5221 is two digital programming potentials (DPP #8482;) integrated control logic and 16 bytes Nvram memory. Each DPP consists of a series of 63 resistors, which are connected between two external access points. The distribution point between each resistor element is connected to the wiper output through the CMOS switch. The separate 6 -bit control register (WCR) independently controls the wiper distribution switch of each DPP. The four -digit non -easy -to -sex memory data register (DR) is associated with each wiper control register, which is used to store up to four wiper settings. Wiper control registers or any non -loss -loss data registers are written through the I2C serial bus. When powering, the contents of the first data register (DR0) of the four potential meters will automatically load them into their respective wiper control registers (WCR).

CAT5221 can be used as potentiometer or two -terminal variable resistors. It is suitable for circuit -level or system -level adjustments in various applications.

pin configuration

function figure

Device operation

cat5221 It is two resistors that integrate the logic of the I2C serial interface, two 6 -bit wiper control registers, and eight 6 -bit non -easy -to -sex memory data registers. Each resistance array contains 63 series of independent resistance elements. The physical end of each array is equivalent to the fixed terminal of the mechanical potentiometer (RH and RL). RH and RL are symmetrical and can be swapped. The tap position at both ends of the series resistors is connected to the output wiper terminal (RW) through the CMOS transistor switch. There is only one sub -connection to its wiper terminal at a division of the potential at a time, andDecided by the wiper control register. The data can be read and write through the I2C bus to the wiper control register or non -loss -loss memory data register. The additional instructions allow data to transmit data between the wiper control register and the non -easy -to -sex data registers of each electrocomputer. In addition, the device can be instructed to run in the increment/reduction mode.

Serial Bus Agree Data transmission can only be started when the bus is not busy.

(2), during the data transmission process, as long as the clock line is high, the data cable must be stable. When the clock is at high, any change in the data cable will be explained as start or stop.

The device that controls the transmission is the main device, usually a processor or controller, and the controlled device is from the device. The host will always start data transmission and provide clocks for sending and receiving operations. Therefore, Cat5221 will be considered device in all applications.

Starting condition

The starting condition is to all commands sent to the device, and define the height conversion of SDA when SCL high. Cat5221 monitor SDA and SCL lines, and will not respond before meeting this condition.

Stop condition

When the SCL is high, the SDA's low to high conversion determines the stop condition. All operations must end at stop conditions.

Device addressing

The bus host began transmission through sending the start -up conditions. The host then sends the address of the specific device requested by it. For Cat5221, the four maximum valid positions of 8 -bit from the machine address are fixed to 0101 (see Figure 5). The next four valid positions (A3, A2, A1, A0) are the device address position, and define which device is visiting. The system can address as many as 16 devices. Generally,+5V and grounding hard connection to these pins to create the address of the device.

After the starting conditions of the main device and the bytes of the machine, the CAT5221 monitoring bus, and responded to the address matching the transmission from the machine address (on the SDA line).

Acknowledged

After the data transmission was successful, each receiving device needs to generate a response. Confirm that the device is pulled down the SDA line within the ninth clock cycle and sent a signal, indicating that it receives 8 -bit data.

CAT5221 responds with confirmation after receiving the start -up condition and its address. If the device is selected while writing the operation, it will respond with the response after receiving each 8 -bit byte.

When CAT5221 is in the read mode, it transmits 8 -bit data, releases the SDA line, and monitors the line to obtainconfirm. Once the confirmation is received, Cat5221 will continue to transmit data. If the host does not send a response, the device terminates the data transmission and waits for the stop condition.

Writing operation

In the writing mode, the main device sends the startup condition and the device address information to the device. After the generating answers, the main device sends instruction bytes to define the request operation of the cat5221. The instruction byte is composed of four -digit operating codes, and the two registers are selected with two registers and two POT options. After receiving another answer from the machine, the data of the main device should be written to the selected register. CAT5221 confirms and the host generates stop conditions. At this time, if a non -loss -loss data register is selected, the device begins to conduct internal programming cycles of non -easy -to -sex memory. When this internal cycle is in progress, the device will not respond to any request from the main device.

Confirm that inquiry

The disable input can be used to use typical writing cycle time. Once the stop condition is issued to indicate the end of the operation of the host, the CAT5221 will start the internal writing cycle. ACK's rotation can start immediately. This involves a startup condition after the machine address is issued. If CAT5221 is still busy writing operation, it will not return to ACK. If the CAT5221 has completed the writing operation, it will return a ACK, and then the host can continue the next instruction operation.

*A0, A1, A2, and A3 corresponding to the pin A0, A1, A2, and A3 of the device.

*A0, A1, A2, and A3 must be compared with its corresponding hard connection input pins.

The manual and register description

instructions

from the address byte

from the main/processor to CAT5221 The first byte is called the/DPP address byte. The four most effective from the machine address are device type identifiers. The CAT5221 is fixed at 0101 [B] (Refer to Table 1).

The next four A3-A0 is the internal port address and must match the physical device address defined by the A3-A0 input pins of the CAT5221 to successfully continue the command sequence. The instructions are executed only from the device that matches the device address sent by the machine address and the host. A3-A0 input can be driven by CMOS input signal active or connected to VCC or VSS.

The instruction byte

The next byte sent to CAT5221 includes instructions and register pointer information. The four maximum effective bits used provide instruction operation code i [3: 0]. P0 digits one of the wiper control registers. At least two valid positions R1 and R0 point to the four of each related potential meterOne of the data registers. The format is shown in Table 2.

Wiper control and data register

Wiper control register (WCR)

21-526 digits include two wiper control potentiometer registers. The wiper control register output is decoded to select one of the 64 switches along its resistor array. The content of WCR can be changed through four ways: the host can write the wiper control register instruction by writing a wiper; you can transmit the contents of a register in the four related data registers through the XFR data register instruction to write it. Modify it step by step (see the instruction part to learn more details). Finally, load the content of its data register 0 (DR0) during power. The wiper control register is an easy -to -loss register. When CAT5221 is powered off, its content will be lost. Although the register automatically loads the value in DR0 during power, this may be different from the value at the time of power off.

Data register (DR)

Each potential meter has four 6 non -easy -to -lose sex data registers. These can be read or written directly by the host. Data can also be transmitted between any of the four data registers and related wiper control registers. Any data change in one of the data registers is non -easy -to -lose -sex operation, which requires up to 5 milliseconds.

If the application does not require multiple settings of the storage potential meter, the data register can be used as a standard storage location for system parameters or user preference data.

The manual

In the nine instructions, there are four lengths of three instructions. These descriptions are:

-The read the wiper control register-read the current wiper position of the potential meter selected in WCR

The current wiper position

-The read the data register-read the content of the selected data register

-Chime write the data register-write the new value to the selected data register

]

The basic sequence of the three -byte instructions is shown in Figure 8. The instructions of these three bytes exchange data between WCR and one of the data registers. WCR controls the position of the wiper. The response of the wiper on this action will be delayed by TWRL. From WCR (current wiper position) to the transmission of data registers is the writing of non -easy -to -sex memory, and at most TWR to complete. The transfer can occur between one of the registers related to it in the four potentials; it can also occur between all potential meters and a related register.

Four instructions require two bytes to be completed, as shown in Figure 7. These fingersOrmore data between the host/processor and the CAT5221; between the host and one of the data registers, or directly transmit the data between the host and the wiper control register. These descriptions are:

-This data register to wiper control register

This will transmit the content of a specified data register to the related wiper control register.

-The wiper control register to data register

This will transmit the contents of the specified wiper control register to the specified related data register.

-Allar transmission data register to the wiper control register

This will transmit the contents of all specified data registers to the relevant wiper control register.

-The global transmission wiper counter register to data register

This will transmit the contents of all wiper control registers to the specified relevant data register.

Increase/reduction command

The last command is the increment/decrement (Figure 5 and Figure 9). Increase/reduction commands are different from other commands. Once the command is issued and the CAT5221 responds, the host can perform the upper and lower clocks selected by the selected wiper in a segment step; thereby providing a fine -tuning function for the host. When the SDA is high, for each SCL clock pulse (thigh), the selected wiper will move a resistance segment to the right terminal. Similarly, when SDA is low, for each SCL clock pulse, the selected wiper will move a resistance segment to the RL terminal.

For more details, see the format of the instructions.

The instruction format

Read the wiper control register (WCR)

[ 123] Write a wiper control register (WCR)

Read the data register (DR)

Write the data register (DR)

Global transmission data register (DR) to wiper control register (WCR)

[123 ] Transfer the wiper control register (WCR) to the data register (DR)

Transfer the wiper control register (WCR) to the data register (DR) [123 ]

Transfer the data register (DR) to the wiper control register (WCR)

Increase (i)/Decreased (d) wiper control register (WCR)

Note: (1), any writing or transmission of non -easy -to -loss data registers will be performed after the issuance stops is issued.High -pressure cycle.

]