Datasheet

725
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
the sensor clock, the sensor data and the sensor data enable signals, refer to the I/O multiplexing table(s) in the
section “Package and Pinout”.
Once enabled, the parallel capture mode samples the data at rising edge of the sensor clock and resynchronizes it
with the peripheral clock domain.
The size of the data which can be read in PIO_PCRHR can be programmed using the DSIZE field in PIO_PCMR.
If this data size is larger than 8 bits, then the parallel capture mode samples several sensor data to form a
concatenated data of size defined by DSIZE. Then this data is stored in PIO_PCRHR and the flag DRDY is set to
one in PIO_PCISR.
The parallel capture mode can be associated with a reception channel of the Peripheral DMA Controller (PDC).
This performs reception transfer from parallel capture mode to a memory buffer without any intervention from the
CPU. Transfer status signals from PDC are available in PIO_PCISR through the flags ENDRX and RXBUFF.
The parallel capture mode can take into account the sensor data enable signals or not. If the bit ALWYS is set to
zero in PIO_PCMR, the parallel capture mode samples the sensor data at the rising edge of the sensor clock only
if both data enable signals are active (at one). If the bit ALWYS is set to one, the parallel capture mode samples
the sensor data at the rising edge of the sensor clock whichever the data enable signals are.
The parallel capture mode can sample the sensor data only one time out of two. This is particularly useful when
the user wants only to sample the luminance Y of a CMOS digital image sensor which outputs a YUV422 data
stream. If the HALFS bit is set to zero in PIO_PCMR, the parallel capture mode samples the sensor data in the
conditions described above. If the HALFS bit is set to one in PIO_PCMR, the parallel capture mode samples the
sensor data in the conditions described above, but only one time out of two. Depending on the FRSTS bit in
PIO_PCMR, the sensor can either sample the even or odd sensor data. If sensor data are numbered in the order
that they are received with an index from zero to n, if FRSTS equals zero then only data with an even index are
sampled. If FRSTS equals one, then only data with an odd index are sampled. If data is ready in PIO_PCRHR and
it is not read before a new data is stored in PIO_PCRHR, then an overrun error occurs. The previous data is lost
and the OVRE flag in PIO_PCISR is set to one. This flag is automatically reset when PIO_PCISR is read (reset
after read).
The flags DRDY, OVRE, ENDRX and RXBUFF can be a source of the PIO interrupt.
Figure 34-11. Parallel Capture Mode Waveforms (DSIZE = 2, ALWYS = 0, HALFS = 0)
0x23 0x34 0x450x12 0x56 0x67 0x78 0x89
0x5645_3423
PIODCCLK
PIODC[7:0]
PIODCEN1
PIODCEN2
DRDY (PIO_PCISR)
RDATA (PIO_PCRHR)
0x01
Read of PIO_PCISR
Peripheral clock