____________________________________________________________________________________________ DS3205

Rev: 111607

9 of 20

3.

Pin Descriptions

Table 3-1. Pin Descriptions

NAME

PIN

TYPE

FUNCTION

ENABLE

1

I

Enable Input. This input pin establishes the board-to-backplane connection when

0 = Disable connection and enter low-power mode.

1 = Enable connection of backplane and board buses.

SCLOUT

2

I/O

Serial Clock Output. This pin is connected to the board’s SCL signal.

SDAOUT

3

I/O

Serial Data Output. This pin is connected to the board’s SDA signal.

ACIE

4

I

Accelerator Current on Inputs Enable. This input pin enables/disables the rise-

time accelerators on the bus input pins.

0 = Disable rise-time accelerator on SCLIN and SDAIN.

1 = Enable rise-time accelerator on SCLIN and SDAIN.

ACOE

5

I

Accelerator Current on Outputs Enable. This input pin enables/disables the rise-

time accelerators on the bus output pins.

0 = Disable rise-time accelerator on SCLOUT and SDAOUT.

1 = Enable rise-time accelerator on SCLOUT and SDAOUT.

ASR

6

I

Accelerator Slew Rate Threshold Select. This input pin selects the rate for the

rise-time accelerators.

0 = 0.8V/

μs

1 = 1.25V/

μs

7

P

Ground

READY

8

Ood

Connected Status Indicator. This is an open-drain output that goes high when the

device is in the ACTIVE state. See the state diagram in Figure 2-3. This pin should

have an external 10k

Ω pullup resistor.

0 = Backplane and board buses not connected.

1 (float) = Backplane and board buses connected.

FAULT

9

Ood

Active-Low Bus Fault Indicator. This open-drain output pin indicates a “stuck bus”

condition when = 0. This pin should have an external 10k

Ω pullup resistor.

0 = Either SCLOUT or SDAOUT has been low > 30ms.

1 = No stuck bus fault.

SBCLK

10

I

Stuck Bus Clocking Enable. Asserting this pin high causes the DS3205 to drive

clock pulses onto the SCLOUT pin in an attempt to free a stuck bus when a “stuck

bus” condition has been detected. See Section 4 and Figure 2-3 for more information

on the stuck bus condition.

0 = Disable automatic clocking during stuck bus fault.

1 = Enable automatic clocking during stuck bus fault.

Note: Asserting both SBDIS and SBCLK high at the same time is not valid and can

produce unwanted results.

SBDIS

11

I

Stuck Bus Disconnect Enable. Asserting this pin high causes the DS3205 to

disconnect the backplane signals from the board signals when a “stuck bus”

condition has been detected. See Section 4 and Figure 2-3 for more information on

the stuck bus condition.

0 = Disable automatic disconnect on stuck bus fault.

1 = Enable automatic disconnect on stuck bus fault.

Note: Asserting both SBDIS and SBCLK high at the same time is not valid and can

produce unwanted results.