afs600 Actel Corporation, afs600 Datasheet - Page 89

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Table 2-36 • Analog Block Pin Description (Continued)
Analog Quad
With the Fusion family, Actel introduces the Analog
Quad, shown in
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
Signal Name
AT7
AV8
AC8
AG8
AT8
ATRETURN89
AV9
AC9
AG9
AT9
RTCMATCH
RTCPSMMATCH
RTCXTLMODE[1:0]
RTCXTLSEL
RTCCLK
Figure 2-65 on page
Number
of Bits
2-76, as the basic
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
Direction
Output
Output
Output
Output
Output
Output
A d v an c ed v1 . 4
Input
Input
Input
Input
Input
Input
Input
Input
Input
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.
The fourth section of the Analog Quad is called the
Temperature Monitor Block, and its input pin name is AT.
This block is similar to the Voltage Monitor Block, except
that it has an additional function: it can be used to
monitor
connected transistor. It has a modified prescaler and is
limited to positive voltages only.
The Analog Quad can be configured during design time
by Actel Libero IDE; however, the ACM can be used to
change the parameters of any of these I/Os during
runtime. This type of change is referred to as a context
switch. The Analog Quad is a modular structure that is
replicated to generate the analog I/O resources. Each
Fusion device supports between 5 and 10 Analog Quads.
The analog pads are numbered to clearly identify both
the type of pad (voltage, current, gate driver, or
Analog Quad 8
Temperature monitor return shared by
Analog Quads 8 and 9
Analog Quad 9
MATCH
MATCH connected to VRPSM
Drives XTLOSC RTCMODE[1:0] pins
Drives XTLOSC MODESEL pin
RTC clock input
the
Actel Fusion Programmable System Chips
Function
temperature
of
an
external
Location of
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Analog Quad
Details
RTC
RTC
RTC
RTC
RTC
diode-
2-75