CY7C65013
CY7C65113
Document #: 38-08002 Rev. *B
Page 25 of 51
This bit indicates whether interrupts are enabled or disabled. Firmware has no direct control over this bit as writing a zero
or one to this bit position has no effect on interrupts. A ‘0’ indicates that interrupts are masked off and a ‘1’ indicates that
the interrupts are enabled. This bit is further gated with the bit settings of the Global Interrupt Enable Register (Figure 14-1)
and USB End Point Interrupt Enable Register (Figure 14-2). Instructions DI, EI, and RETI manipulate the state of this bit.
Bit 3: Suspend
Writing a ‘1’ to the Suspend bit halts the processor and cause the microcontroller to enter the suspend mode that signifi-
cantly reduces power consumption. A pending, enabled interrupt or USB bus activity causes the device to come out of
suspend. After coming out of suspend, the device resumes firmware execution at the instruction following the IOWR which
put the part into suspend. An IOWR attempting to put the part into suspend is ignored if USB bus activity is present. See
Section 8.0 for more details on suspend mode operation.
Bit 4: Power-on Reset
The Power-on Reset is set to ‘1’ during a power-on reset. The firmware can check bits 4 and 6 in the reset handler to
determine whether a reset was caused by a power-on condition or a Watchdog timeout. A POR event may be followed by
a Watchdog reset before firmware begins executing, as explained below.
Bit 5: USB Bus Reset Interrupt
The USB Bus Reset Interrupt bit is set when the USB Bus Reset is detected on receiving a USB Bus Reset signal on the
upstream port. The USB Bus Reset signal is a single-ended zero (SE0) that lasts from 12 to 16
µs. An SE0 is defined as
the condition in which both the D+ line and the D– line are LOW at the same time. .
Bit 6: Watchdog Reset
The Watchdog Reset is set during a reset initiated by the Watchdog Timer. This indicates the Watchdog Timer went for
more than tWATCH (8 ms minimum) between Watchdog clears. This can occur with a POR event, as noted below.
Bit 7: IRQ Pending
The IRQ pending, when set, indicates that one or more of the interrupts has been recognized as active. An interrupt remains
pending until its interrupt enable bit is set (Figure 14-1, Figure 14-2) and interrupts are globally enabled. At that point, the
internal interrupt handling sequence clears this bit until another interrupt is detected as pending.
During power-up, the Processor Status and Control Register is set to 00010001, which indicates a POR (bit 4 set) has occurred
and no interrupts are pending (bit 7 clear). During the 96-ms suspend at start-up (explained in Section 7.1), a Watchdog Reset
also occurs unless this suspend is aborted by an upstream SE0 before 8 ms. If a WDR occurs during the power-up suspend
interval, firmware reads 01010001 from the Status and Control Register after power-up. Normally, the POR bit should be cleared
so a subsequent WDR can be clearly identified. If an upstream bus reset is received before firmware examines this register, the
Bus Reset bit may also be set.
During a Watchdog Reset, the Processor Status and Control Register is set to 01XX0001, which indicates a Watchdog Reset (bit
6 set) has occurred and no interrupts are pending (bit 7 clear). The Watchdog Reset does not effect the state of the POR and the
Bus Reset Interrupt bits.
14.0
Interrupts
Interrupts are generated by GPIO pins, internal timers, I2C-compatible operation, internal USB hub and USB traffic conditions.
All interrupts are maskable by the Global Interrupt Enable Register and the USB End Point Interrupt Enable Register. Writing a
‘1’ to a bit position enables the interrupt associated with that bit position.
Bit 0 : USB Bus RST Interrupt Enable
1 = Enable Interrupt on a USB Bus Reset; 0 = Disable interrupt on a USB Bus Reset (Refer to section 14.3).
Bit 1 :128-
µs Interrupt Enable
1 = Enable Timer interrupt every 128
µs; 0 = Disable Timer Interrupt for every 128 µs.
Bit 2 : 1.024-ms Interrupt Enable
Global Interrupt Enable Register
Address 0X20
Bit #
76543210
Bit Name
Reserved
I2C Interrupt
Enable
GPIO
Interrupt
Enable
Reserved
USB Hub
Interrupt
Enable
1.024-ms
Interrupt
Enable
128-
µs
Interrupt
Enable
USB Bus
RST
Interrupt
Enable
Read/Write
–
R/W
R/W
-
R/W
R/W
R/W
R/W
Reset
–00
X
0000
Figure 14-1. Global Interrupt Enable Register
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