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NXP Semiconductors
PNX15xx/952x Series
Volume 1 of 1
Chapter 14: FGPI: Fast General Purpose Interface
PNX15XX_PNX952X_SER_N_4
NXP B.V. 2007. All rights reserved.
Product data sheet
Rev. 4.0 — 03 December 2007
14-498
3.3 PNX1300 Series Message Passing Mode
PNX1300 Series Message Passing mode can be emulated by setting FGPI_SIZE to
1 and only enabling buffer 1 (FGPI_CTL.CAPTURE_ENABLE_1 = ‘1’).
3.4 Record Capture Mode
Only active clock edges where fgpi_d_valid is asserted ‘1’ allow data samples to be
captured.
If FGPI_REC_SIZE is not a multiple of 4 bytes, the record will be written to main
memory as a series of 32-bit words. Only the last word is padded with zeroes in the
unused bit positions.
Record start is signaled on the fgpi_start (fgpi_rec_start) pin. See
FGPI_CTL.MSG_START (REC_SYNC) for selecting which edge will be active.
Buffer switching is signaled on the fgpi_stop (fgpi_buf_start) pin. See
FGPI_CTL.MSG_STOP (BUF_SYNC) for selecting which buffer sync method will be
used.
3.4.1
Record Synchronization
Starting capture of sample data for each record is signaled by a record start event
(selected by the FGPI_CTL.REC_SYNC bits):
a rising edge on fgpi_start (fgpi_rec_start) pin
a falling edge on fgpi_start (fgpi_rec_start) pin
occur immediately after the previous buffer is lled or when capture is started
The record ends by reaching the programmed record size in the FGPI_REC_SIZE
register or by the next record start event, whichever comes rst.
For rising and falling edge record start events the record may reach the programmed
record size before the next record start event starts a new record. In this case the
FGPI will stop sampling data and wait for the next record start event to continue lling
the current buffer. The record may also be terminated by receiving the next record
start event before the end of the current record. In this case the record is only partially
lled, the content of the rest of the record is undened.
When no record sync is used data is sampled continuously. This leads to back-to-
back recording of consecutive records, independent of the fgpi_start (fgpi_rec_start)
pin state. Each record is exactly the programmed size in the FGPI_REC_SIZE
register.
3.4.2
Buffer Synchronization
It is possible to further synchronize the recording of sample data to a buffer start
event. (selected by the FGPI_CTL.BUF_SYNC bits):