DS4550 Datasheet, PDF (6/18 Pages) Dallas Semiconductor – I2C and JTAG Nonvolatile 9-Bit I/O Expander Plus Memory

I²C and JTAG Nonvolatile 9-Bit I/O
Expander Plus Memory
Pin Description
PIN
NAME
FUNCTION
1
I/O_0
Input/Output 0. Bidirectional I/O pin.
2
I/O_1
Input/Output 1. Bidirectional I/O pin.
3
I/O_2
Input/Output 2. Bidirectional I/O pin.
4
I/O_3
Input/Output 3. Bidirectional I/O pin.
5
I/O_4
Input/Output 4. Bidirectional I/O pin.
6
A0
I²C Address Input. Inputs A0, A1, and A2 determine the I²C slave address of the device.
7
A1
I²C Address Input. Inputs A0, A1, and A2 determine the I²C slave address of the device.
8
TCK
JTAG Test Clock. This signal is used to shift data into TDI on the rising edge and out of TDO on the
falling edge.
9
TMS
JTAG Test Mode Select. This pin is sampled on the rising edge of TCK and used to place the TAP
into the various defined JTAG states. This pin has an internal pullup resistor.
10
V_CC
Power Supply Voltage
11
SDA
I²C Serial Data Open-Drain Input/Output
12
SCL
I²C Serial Clock Input
13
TDI
JTAG Test Data Input. Test instructions and data are clocked into this pin on the rising edge of TCK.
This pin has an internal pullup resistor.
14
TDO
JTAG Test Data Output. Test instructions and data are clocked out of this pin on the falling edge of
TCK. If not used, this pin should be left open circuit.
15
A2
I²C Address Input. Inputs A0, A1, and A2 determine the I²C slave address of the device.
16
I/O_5
Input/Output 5. Bidirectional I/O pin.
17
I/O_6
Input/Output 6. Bidirectional I/O pin.
18
I/O_7
Input/Output 7. Bidirectional I/O pin.
19
I/O_8
Input/Output 8. Bidirectional I/O pin.
20
GND
Ground
6 _____________________________________________________________________