afs600 Actel Corporation, afs600 Datasheet - Page 45

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

Real-Time Counter System
The addition of the RTC system enables Fusion devices to
support both standby and sleep modes of operation,
greatly
applications.
The RTC system comprises six blocks that work together to
provide this increased functionality and reduced power
consumption.
are connected.
Figure 2-27 • Real-Time Counter System
Figure 2-28 • RTC Block Diagram
• RTC
• Crystal oscillator
• V
CC33UP
reducing
(Figure
XTAL1
XTAL2
Crystal Oscillator
Figure 2-27
detector
EN
MODE[1:0]
2-28)
CLKOUT
power
0
7-Bit Prescaler
(Crystal ÷ 128)
shows these blocks and how they
consumption
ACM
SELMODE
RTCCLK
RTCMODE[1:0]
RTCPSMMATCH
RTC
RTCMATCH
Analog Configuration MUX (ACM) Interface
1.5/3.3 Volt Level Shift Circuitry
40-Bit Match
Control/Status
in
Counter
Register
FPGA Fabric
Register
40-Bit
Flash Bits
VRINITSTATE
many
A d v an c ed v1 . 4
VCC33UP
From
Core Flash
Bits
VR Init
The RTC provides a counter as well as a MATCH output
signal that can be used in the FPGA and, optionally, to
power up the on-chip 1.5 V voltage regulator and
provide a 1.5 V power source (in conjunction with an
external pass transistor) to the FPGA fabric portion of the
Fusion silicon device. The FPGA fabric can then be used
to power down the 1.5 V voltage regulator.
• Voltage regulator initialization
• Voltage regulator logic
• 1.5 V voltage regulator
FPGA_VRON
RTCPSMMATCH
40 XNORs
Read-Hold
VR Logic
Register
40-Bit
~ VRPSM
VRON
Actel Fusion Programmable System Chips
Match
Bits
VRFPD
VRPU
1.5 V FPGA Supply Input
1.5 V Voltage
Regulator
Match
Main
Registers
PTBASE
PTEM
PUB
3.3 V
External
Pass
Transistor
Output
1.5 V
Power-Up/Down
Toggle Control
Switch
2-31