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Data Sheet
99
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description E1/T1/J1
Masked Interrupts Visible in Status Registers
The “Global” Interrupt Status register (GIS) indicates those interrupt status registers with active interrupt
indications (bits GIS.ISR(7:0)).
An additional interrupt mode can be selected per port via bit GCR.VIS (GCR_E, GCR_T), see Table 11. In this
mode, masked interrupt status bits neither generate an interrupt on pin INT nor are they visible in GIS, but are
displayed in the corresponding interrupt status register(s) ISR(7:0).
PLL Interrupt Status Register
In compatibility mode (GPC6.COMP_DIS = 0
B), the PLL status is indicated by bit 7 of the register CIS as bit
PLLL.
In generic mode (GPC6.COMP_DIS = 1
B) the PLL status PLLLS is not visible in the bit 7 of the register CIS
but in register GIS2.
The Global Interrupt Status register GIS2 indicates the lock status of the (global) PLL. Masking can be done
by the register GIMR.
An additional interrupt mode can be selected per port via bit IPC.VISPLL (IPC_E) where the masked interrupt
status bit GIS2.PLLLS does not generate an interrupt on pin INT, but is displayed in the corresponding
interrupt status register bit GIS2.PLLLC, see Table 11.
The additional interrupt mode is useful when some interrupt status bits are to be polled in the individual interrupt
status registers.
Note: In the visible mode, all active interrupt status bits, whether the corresponding actual interrupt is masked or
not, are reset when the interrupt status register is read. Thus, when polling of some interrupt status bits is
desired, care must be taken that unmasked interrupts are not lost in the process.
1. The behaviour of all unmasked interrupts does not change in visible mode.
Please note that whenever polling is used, all interrupt status registers concerned have to be polled individually
(no “hierarchical” polling possible), since GIS only contains information on actually generated, i.e. unmasked
interrupts.
3.4.5
Boundary Scan Interface
In the QuadFALC
TM a Test Access Port (TAP) controller is implemented. The essential part of the TAP is a finite
state machine (16 states) controlling the different operational modes of the boundary scan. Both, TAP controller
and boundary scan, meet the requirements given by the JTAG standard IEEE 1149.1-2001. Figure 21 gives an
overview, Figure 102 shows the timing diagram and Table 144 gives the appropriate values of the timing
parameters.
Table 11
Interrupt Modes
GCR.VIS; IPC.VISPLL
Appropriate Mask Bit
Interrupt Active
Visibility in ISR(7:0) ; GIS2
00
Yes
01
No
10
Yes
11
No
Yes