AMIS-53000 Datasheet, PDF (90/99 Pages) AMI SEMICONDUCTOR – Frequency Agile Transceiver

AMIS-53000 Frequency Agile Transceiver
Data Sheet
8.0 General System Functions
8.1 Pull up Disable
The AMIS-53000 includes built in pull-up resistors for use with the I²C operation to reduce the overall system component count. The
pull ups are asserted at POR until mode selection occurs. If mode is determined to be 3-wire, the pull ups are removed. If mode is
determined to be I²C, this option bit determines whether the pull ups are to be removed.
Table 109: I²C Pull Up Control
Register
Number (HEX) Name
0X0C
General Options A
Function
Bits
3
Disable internal pull up resistors on I²C bus
8.2 Brown-Out POR
The brown-out POR serves two purposes. The first is to provide a POR signal to reset the digital when power is initially applied to the
part. The second is to provide a POR should the voltage on the supply drift below normal operating range to prevent a brown-out
condition.
Table 110: Power-on-Reset Start Up State
Register
Number (HEX) Name
Bits
0X0C
General Options A 2,1
Function
00 Standby
01 Idle
10 RX
11 TX
8.3 Temperature Sensor
The temperature sensor is created by using a Darlington pair of PNP transistors. The two transistors create a 5mV/^oC slope that can
be sensed with an analog to digital converter. Without amplification, an 8 bit ADC with a 2V reference voltage will have a resolution
better than two degrees.
The temperature sensor can be trimmed to an accuracy of 3°C. As the trim is increased, the output voltage also increases.
The temperature voltage relationship is given by:
Where V is the output voltage and T is the temperature in Celsius.
Setup registers descriptions:
ADC Temperature- Register shows the value of the temperature sensor ADC. (See Section 6.13.1.1)
AMI Semiconductor – Aug. 05, Rev. 1.0
90
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