Device Architecture
2- 84
Pr el iminar y v1 .7
Analog Quad
the basic analog I/O structure. The Analog Quad is a four-channel system used to precondition a set
of analog signals before sending it to the ADC for conversion into a digital signal. To maximize the
usefulness of the Analog Quad, the analog input signals can also be configured as LVTTL digital
input signals. The Analog Quad is divided into four sections.
The first section is called the Voltage Monitor Block, and its input pin is named AV. It contains a
two-channel analog multiplexer that allows an incoming analog signal to be routed directly to the
ADC or allows the signal to be routed to a prescaler circuit before being sent to the ADC. The
prescaler can be configured to accept analog signals between –12 V and 0 or between 0 and +12 V.
The prescaler circuit scales the voltage applied to the ADC input pad such that it is compatible with
the ADC input voltage range. The AV pin can also be used as a digital input pin.
The second section of the Analog Quad is called the Current Monitor Block. Its input pin is named
AC. The Current Monitor Block contains all the same functions as the Voltage Monitor Block with
one addition, which is a current monitoring function. A small external current sensing resistor
(typically less than 1
Ω) is connected between the AV and AC pins and is in series with a power
source. The Current Monitor Block contains a current monitor circuit that converts the current
through the external resistor to a voltage that can then be read using the ADC.
The third part of the Analog Quad is called the Gate Driver Block, and its output pin is named AG.
This section is used to drive an external FET. There are two modes available: a High Current Drive
mode and a Current Source Control mode. Both negative and positive voltage polarities are
available, and in the current source control mode, four different current levels are available.
ATRETURN67
1
Input
Temperature monitor return shared
by Analog Quads 6 and 7
Analog Quad
AV7
1
Input
Analog Quad 7
Analog Quad
AC7
1
Input
Analog Quad
AG7
1
Output
Analog Quad
AT7
1
Input
Analog Quad
AV8
1
Input
Analog Quad 8
Analog Quad
AC8
1
Input
Analog Quad
AG8
1
Output
Analog Quad
AT8
1
Input
Analog Quad
ATRETURN89
1
Input
Temperature monitor return shared
by Analog Quads 8 and 9
Analog Quad
AV9
1
Input
Analog Quad 9
Analog Quad
AC9
1
Input
Analog Quad
AG9
1
Output
Analog Quad
AT9
1
Input
Analog Quad
RTCMATCH
1
Output
MATCH
RTC
RTCPSMMATCH
1
Output
MATCH connected to VRPSM
RTC
RTCXTLMODE[1:0]
2
Output
Drives XTLOSC RTCMODE[1:0] pins
RTC
RTCXTLSEL
1
Output
Drives XTLOSC MODESEL pin
RTC
RTCCLK
1
Input
RTC clock input
RTC
Table 2-36 Analog Block Pin Description (continued)
Signal Name
Number
of Bits
Direction
Function
Location of
Details