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NXP Semiconductors
PNX15xx/952x Series
Volume 1 of 1
Chapter 8: General Purpose Input Output Pins
PNX15XX_PNX952X_SER_N_4
NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 4.0 — 03 December 2007
8-284
The 12 timestamp unit interrupts are ORed together (if enabled) to produce one
interrupt. Therefore the 12 TSUs produce only one interrupt, see
Table 5 onAll the interrupt status bits are ‘sticky’ bits and can only be cleared by writing a ‘1’ to
the relevant interrupt clear register. The GPIO status MMIO register,
VIC_INT_STATUS
Section 4.9, stores information about whether a FIFO queue or a
TSU caused the interrupt.
2.7 Timer Sources
Any of the GPIO pins or internal signals can be selected as a timer source for
2.8 Wake-up Interrupt
An interrupt called ‘gpio_interrupt’ is generated whenever the GPIO module requests
an interrupt. This event is a ‘wake-up’ interrupt for the clock module to turn back on
the system clocks once the PNX15xx/952x Series has been sent into deep sleep
mode.
2.9 External Watchdog
Any of the GPIO pin can be used in case of an external watchdog style reset
generator as the output which is pulsed regularly by software to keep a reset from
occurring. WDOG_OUT pin is a regular GPIO pin without any special properties, and
can be used as an extra GPIO if no watchdog reset is present.
3.
IR Applications
For each FIFO queue programmed in signal monitoring or pattern generation modes,
it is possible to divide the 108 MHz clock to obtain suitable frequencies for Ir
applications.
As well as the 16-bit divider to divide the 108 MHz clock, each FIFO queue has a
further 5-bit divider which can be enabled if sub-carrier frequencies are required for
transmission. Therefore, in Ir applications, a FIFO queue can produce Ir signals at a
Table 5: Example of IR Characteristics
PROTOCOL
MIN. PULSE
REQ. FREQ
FREQ_DIV[15:0]
CARRIER_DIV[4:0]
Error (%)
CIR (IrDA Control)
6.67
s
150 kHz
0x2D0
0x1 or Disabled
0
CIR with Sub-Carrier (TX)
0.667
s
1.5 MHz
0x24
0x14
0
RC-MM
27.77
s
36 kHz
0xBB8
0x1 or Disabled
0
RC-MM Sub-Carrier
9.26
sa
108 kHz
0x1F4
0x6
0
a RF sub-carrier is 36kHz, ONTIME should be between 25-50% of 27.77us period. (108KHz = 33%)