TMP100−EP, TMP101−EP

DIGITAL TEMPERATURE SENSOR

SGLS254A − JULY 2005 - REVISED APRIL 2010

12

POST OFFICE BOX 655303

APPLICATION INFORMATION

SMBus alert function

The TMP101 supports the SMBus Alert function. When the TMP101 is operating in Interrupt Mode (TM = 1),

the ALERT pin of the TMP101 may be connected as an SMBus Alert signal. When a master senses that an

ALERT condition is present on the ALERT line, the master sends an SMBus Alert command (00011001) on the

bus. If the ALERT pin of the TMP101 is active, the TMP101 acknowledges the SMBus Alert command and

responds by returning its slave address on the SDA line. The eighth bit (LSB) of the slave address byte indicates

If multiple devices on the bus respond to the SMBus Alert command, arbitration during the slave address portion

of the SMBus alert command determines which device clears its ALERT status. If the TMP101 wins the

arbitration, its ALERT pin becomes inactive at the completion of the SMBus Alert command. If the TMP101 loses

the arbitration, its ALERT pin remains active.

The TMP100 also responds to the SMBus ALERT command if its TM bit is set to 1. Since it does not have an

ALERT pin, the master needs to periodically poll the device by issuing an SMBus Alert command. If the TMP100

has generated an ALERT, it acknowledges the SMBus Alert command and returns its slave address in the next

byte.

general call

acknowledges the general call address and responds to commands in the second byte. If the second byte is

00000100, the TMP100 and TMP101 latch the status of their address pins, but will not reset. If the second byte

is 00000110, the TMP100 and TMP101 latch the status of their address pins and reset their internal registers.

high-speed mode

master code (00001XXX) as the first byte after a START condition to switch the bus to high-speed operation.

input filters on SDA and SCL and their output filters on SDA to operate in Hs-mode, allowing transfers at up to

a data transfer operation. The bus continues to operate in Hs-mode until a STOP condition occurs on the bus.

Upon receiving the STOP condition, the TMP100 and TMP101 switch their input and output filters back to

fast-mode operation.

timing diagrams

operations on the TMP100 and TMP101. Bus definitions are given below. Parameters for Figure 5 are defined

in Table 13.

Bus Idle: Both SDA and SCL lines remain high.

Start Data Transfer: A change in the state of the SDA line, from high-to-low, while the SCL line is high, defines

a START condition. Each data transfer is initiated with a START condition.

Stop Data Transfer: A change in the state of the SDA line from low-to-high while the SCL line is high defines

a STOP condition. Each data transfer is terminated with a repeated START or STOP condition.

Data Transfer: The number of data bytes transferred between a START and a STOP condition is not limited

and is determined by the master device. The receiver acknowledges the transfer of data.