PNX1501E NXP Semiconductors, PNX1501E Datasheet - Page 387

• Manufacturer Part Number: PNX1501E
• Description: Digital Signal Processors & Controllers (DSP, DSC) MEDIA PROCESSOR PNX15XX/266MHZ
• Manufacturer: NXP Semiconductors

Specifications of PNX1501E

• Product: DSPs
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-795
• Minimum Operating Temperature: 0 C
• Lead Free Status / Rohs Status: Details
• Other names: PNX1501E,557

Philips Semiconductors
Volume 1 of 1
12NC 9397 750 14321
Product data sheet
4.8.1 Layer Underflow
4.8.2 Underflow Symptom
4.8.3 Underflow Recovery
4.8.4 Underflow Trouble-shooting
4.8.5 Underflow Handling
Any time the layer position has reached but the small 16-pixel FIFO at the end of
every layer pipe has run out of available pixels, underflow occurs.
Should an underflow occur, the layer would fetch and dump remaining data for the
current field/frame. The next field/frame would be fetched and displayed as normal.
The underflow interrupt status would stay asserted until an interrupt-status-clear is
programmed.
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Only portion of a picture is displayed or occasional blinking of picture happens
Underflow interrupt bit is set.
Check if the DMA source width settings (0x10,Ex08) matches the initial layer
width (0x10,Ex34)
Check if the initial layer width (0x10,Ex34) matches the final layer width
(0x10,ExB4) for the non-scaled layer.
Check if the final layer width (0x10,ExB4) is within acceptable cropping range for
LINT or HSRU scaling.
Check whether the DMA start fetch (0x10,ExC8) is at line number too close to the
display position. Note that about 64 pixels is QVCP’s input-to-output latency. So,
depending on the system-memory latency, the DMA fetch should start as early as
possible, in order to make up for the request-to-data latency.
Check if the system memory arbiter is giving high priority to QVCP.
Check if QVCP demands exceed allocated memory bandwidth.
Rev. 2 — 1 December 2004
© Koninklijke Philips Electronics N.V. 2002-2003-2004. All rights reserved.
PNX15xx Series
Chapter 11: QVCP
11-41