Datasheet

DS3930
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
(R
I/O
) with bits 7 to 4 and the I/O pin setting with bits 3
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 Set to 0 to enable I/O
3
pullup, set to 1 to disable pullup
Bit 6 Set to 0 to enable I/O
2
pullup, set to 1 to disable pullup
Bit 5 Set to 0 to enable I/O
1
pullup, set to 1 to disable pullup
Bit 4 Set to 0 to enable I/O
0
pullup, set to 1 to disable pullup
Bit 3 Sets I/O
3
to 0 or 1
Bit 2 Sets I/O
2
to 0 or 1
Bit 1 Sets I/O
1
to 0 or 1
Bit 0 Sets I/O
0
to 0 or 1
F7h 0X I/O State
Bit 7 0
Bit 6 0
Bit 5 0
Bit 4 0
Bit 3 Contains state of I/O
3
pin (read only)
Bit 2 Contains state of I/O
2
pin (read only)
Bit 1 Contains state of I/O
1
pin (read only)
Bit 0 Contains state of I/O
0
pin (read only)
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
11Pullup disabled (HI-Z)
Table 1. I/O Pin Truth Table