M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 38

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Device Architecture
2- 22
Figure 2-18 • Crystal Oscillator: RC Time Constant Values vs. Frequency (typical)
Table 2-10 • XTLOSC Signals Descriptions
Signal Name
XTL_EN*
XTL_MODE*
SELMODE
RTC_MODE[1:0]
MODE[1:0]
FPGA_EN*
XTL
CLKOUT
Note:
*Internal signal—does not exist in macro.
1.00E-0.3
1.00E-0.4
1.00E-0.5
1.00E-0.6
1.00E-0.7
Width
0.0
2
2
1
1
1
2
1
1
Direction
0.5
OUT
IN
IN
IN
IN
IN
RC Time Constant Values vs. Frequency
1.0
Enables the crystal. Active high.
Settings for the crystal clock for different frequency.
Value
b'00
b'01
b'10
b'11
Selects the source of XTL_MODE and also enables the
XTL_EN. Connect from RTCXTLSEL from AB.
0
1
Settings for the crystal clock for different frequency ranges.
XTL_MODE uses RTC_MODE when SELMODE is '1'.
Settings for the crystal clock for different frequency ranges.
XTL_MODE uses MODE when SELMODE is '0'. In Standby,
MODE inputs will be 0's.
0 when 1.5 V is not present for V
V
Crystal Clock source
Crystal Clock output
CC
R e visio n 1
Frequency (MHz)
1.5
For normal operation or sleep mode, XTL_EN
depends on FPGA_EN, XTL_MODE depends on
MODE
For
XTL_MODE depends on RTC_MODE
2.0
Medium gain
RC network
Standby
High gain
Low gain
Modes
2.5
Function
3.0
mode,
CC
3.5
1 when 1.5 V is present for
XTL_EN
Frequency Range
32 KHz to 4 MHz
0.20 to 2.0 MHz
2.0 to 20.0 MHz
32 to 200 KHz
4.0
is
4.5
enabled,