
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
8-283
2.5 The GPIO Clock Pins
GPIO[14:12,6:4] pins can be assigned to drive a clock generated from the clock
module. These are clocks generated by DDS clock generators.
Table 4 shows the
mapping between DDS clocks and the GPIO pins through which they are routed to.
The clocks on pins 4, 5 and 6 can be used as clock sources for the FIFO queues. In
this case the clocks are rst routed to the pins, GPIO[4], GPIO[5] and GPIO[6], and
then brought back inside the chip as any other external clock source would be. To use
this feature the GPIO_EV register should be programmed in the following way:
GPIO_EV.EN_CLOCK_SEL = enabled, i.e. set to binary code 01 or 11
GPIO_EV.EN_DDS_SOURCE = enabled, i.e. set to ‘1’.
GPIO_EV.CLOCK_SEL = select between pins 4, 5 or 6
The clocks are selectable individually.
The clocks on pins 12, 13 and 14 are only routed to the PNX15xx/952x Series pins
and can be used as clock sources for some external devices, or loop back on the
system board to GPIO[3:0]. They are not directly used as internal clock sources for
the FIFO queues. In order to route the clocks on these GPIO[14:12] pins, the
DDS_OUT_SEL MMIO register should be programmed appropriately.
2.6 GPIO Interrupts
Each operating FIFO queue can generate 4 types of interrupts:
BUF1_READY: DMA buffer 1 ready for reading or writing
BUF2_READY: DMA buffer 2 ready for reading or writing
FIFO_OE: DMA buffer overrun error
INT_OE: Internal buffering overrun error.
Each timestamp unit has 2 types of interrupts:
DATA_VALID: TSU has data ready to be read
INT_OE: Internal buffering overrun error
Each FIFO queue has its own interrupt line to the TM3260 CPU, see
Table 5 onTable 4: GPIO clock sources
GPIO[x] pin
Possible Clock Source
14
DDS0 or DDS2 (The selection is made in the clock module)
13
DDS5 or DDS1 (The selection is made in the clock module)
12
DDS6
6
DDS6
5
DDS7
4
DDS8