DP7140

8

Address 1: Device ID (Read Only)

Bit 7 defines the DP device manufacturer; COPAL ELECTRONICS = high (1)

Bit

7

6

5

4

3

2

1

0

Name

1

1

0

1

0

0

0

0

A writing to address 1 has no effect. Attempts to do so will return an ACK but no data will be written.

Address 0: IVR/WR Register (I/O)

Address 00h accesses one of two memory registers: the initial value register (IVR) or the wiper register (WR) depending

upon the value of bit 7 in Access Control Register (ACR) which is at address 08h, above.

WR controls the wiper s position and is a volatile memory while IVR is non volatile and retains its data after the chip has

been powered down. Writes to IVR automatically update the WR while writes to WR leave IVR unaffected.

WR: Wiper Register = Volatile.

IVR: Initial Value Register = Non volatile.

Writing and Reading operations:

1. If Bit 7 from ACR is 0 (non volatile):

A write operation to address 00h will write the same value in WR and IVR.

A read operation to address 00h will output the content of IVR.

2. If bit 7 from ACR is 1 (volatile):

A write operation to address 00h will write in WR only.

A read operation to address 00h will output the content of WR.

All changes to the wiper s position are immediate. There is no delay the wiper s movement when writing to non volatile

memory.

Bit

7

6

5

4

3

2

1

0

Name

IVR is preprogrammed at the factory to a default value of “80h”.

Transfer Data

Slave Address

R/W bit

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

Read

51h

0

1

0

1

0

0

0

1 (R)

Write

50h

0 (W)

If the Slave Address Byte sent by the host is different the device will send a NoACK.

1. Host transfers the start condition

2. Host transfers the device slave address with the write mode R/W bit (0).

3. Device sends ACK

4. Host transfers the corresponding memory address to the device

5. Device sends ACK

6. Host transfers the write data to the designated address

7. Device sends ACK

8. Routines (6) and (7) are repeated based on the transfer data, and the designated address is automatically incremented*

9. Host transfers the stop condition.

*Automatically incremented writes are not possible after a non volatile write.