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CY7C68320C/CY7C68321C
Document 001-05809 Rev. *A Page 12 of 42
SYSIRQ
The SYSIRQ pin provides a way for systems to request service
from host software by using the USB Interrupt pipe on endpoint
1 (EP1). If the AT2LP has no pending interrupt data to return,
USB interrupt pipe data requests are NAKed. If pending data
is available, the AT2LP returns 16 bits of data. This data
indicates whether AT2LP is operating in high-speed or
full-speed, whether the AT2LP is reporting self-powered or
bus-powered operation, and the states of any GPIO pins that
are configured as inputs. GPIO pins can be individually set as
inputs or outputs, with byte 0x09 of the configuration data. The
state of any GPIO pin that is not set as an input is reported as
‘0’ in the EP1 data.
Table 3 gives the bitmap for the data returned on the interrupt
pipe and Figure 8 depicts the latching algorithm incorporated
by the AT2LP.
The SYSIRQ pin must be pulled LOW if HID functionality is
used. Refer to “HID Functions for Button Controls” on page 15
for more details on HID functionality.
Table 3. Interrupt Data Bitmap
EP1 Data Byte 1 EP1 Data Byte 0
7654321076543210
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
RESERVED
USB High-Speed
VBUS Powered
RESERVED
RESERVED
GPIO[5]
GPIO[4]
GPIO[3]
GPIO[2]
GPIO[1]
GPIO[0]
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