Hex Nonvolatile Potentiometer with

I/O and Memory

8

______________________________________________________________________

I/O Signals

The I/O pins can be used as general-purpose digital

I/O signals. The I/O pins have CMOS outputs with an

internal pullup resistor (see Figure 2). The I/O pins are

configured with the I/O Control register (F6h) and moni-

tored with the I/O State register (F7h). The I/O Control

register controls the state of the internal pullup resistor

to 0 (see Table 1). The read-only values of the I/O State

register contains the values of the I/O pin setting bits of

the I/O Control register unless the I/O output is tri-stat-

ed. When the I/O is tri-stated the I/O State register will

read high or low depending on the external source on

the I/O pin. Since the I/O pins are controlled by EEP-

ROM, the number of writes is limited.

Memory

The memory map is shown in Table 2.

Table 2. Memory Map

ADDRESS

BIT

DEFAULT (HEX)

FUNCTION

00h to 3Fh

FF

64 bytes of general-purpose EEPROM

40h to EFh

FF

Reserved

F0h

FF

Controls potentiometer 0

F1h

FF

Controls potentiometer 1

F2h

FF

Controls potentiometer 2

F3h

FF

Controls potentiometer 3

F4h

FF

Controls potentiometer 4

F5h

FF

Controls potentiometer 5

F6h

0F

I/O Control

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

F7h

0X

I/O State

Bit 7

0

Bit 6

0

Bit 5

0

Bit 4

0

Bit 3

Bit 2

Bit 1

Bit 0

F8h to FFh

FF

Reserved

PULLUP CTRL

(I/O CONTROL

REGISTER)

(BITS 7 TO 4)

I/O PIN SETTING

(I/O CONTROL

REGISTER)

(BITS 3 TO 0)

I/O PIN OUTPUT

00

0

01

1

10

0

11

Pullup disabled (HI-Z)

Table 1. I/O Pin Truth Table