
camisp-090
Write to ENABLE bit
RSZ_PCR[1] BUSY
Write
RSZ_PCR[0] ENABLE =0x1
CAM_IRQ
Write
RSZ_PCR[0] ENABLE =0x1
Public Version
Camera ISP Basic Programming Model
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6.5.8.2
Camera ISP Resizer Enable/Disable Hardware
Setting the
[0] ENABLE bit to 0x1 enables the resizer. This must be done after all required
registers are programmed.
When the input source is memory, the resizer always operates in one-shot mode. In other words, after
enabling the resizer, the
[0] ENABLE bit is automatically turned off (set to 0) and only a single
frame is processed from memory.
In this mode, fetching and processing of the frame begin immediately on setting the
[0]
ENABLE bit.
When the input source is the CCDC or preview engine, the resizer can be configured to operate in either
one-shot mode, or continuous mode (
[2] ONESHOT). Processing of theframe depends on the
timing of the CCDC/Preview. To ensure that data from the CCDC or preview engine is not missed, the
resizer must be enabled before to these upstream modules, so it waits for data from the CCDC or the
preview engine.
When the resizer is started during an ongoing frame the enable is latched at the end of the frame it was
written in.
When the resizer is in continuous mode, it can be disabled by clearing the ENABLE bit during the
processing of the last frame. The disable is latched in at the end of the frame in which it was written.
6.5.8.3
Camera ISP Resizer Events and Status Checking
The resizer generates an interrupt event at the end of each frame.
The status of this interrupt can be checked by reading the
register (or
). When the read of the register
occurs (or
), the
register is not automatically reset. To reset the interrupt, a 1 must be written to the RSZ_DONE_IRQ bit.
Each event that generates an interrupt can be individually mapped to ARM or DSP using the
register (or
). When a particular event is not enabled (for example
[x] = 0), the correspondent status (
[x] = 1) bit is flagged, if the
correspondent event occurs. This has no effect on the interrupt line, but can be used by software to poll
the status.
The
[1] BUSY status bit is set when the start of frame occurs (if the
[0] ENABLE bit is
1 at that time). It is automatically reset to 0 at the end of a frame. The
[1] BUSY status bit may
be polled to determine end-of-frame status in oneshot mode.
shows the firmware/hardware
interaction. Configuration registers and filter coefficients are programmed in-between or before busy
periods, before writing ENABLE to 0x1.
Figure 6-119. Camera ISP Resizer Firmware Interactions for Memory-Input Resizing
NOTE:
The
[19:10] RSZ_EXP bit field enables the spreading of non-real time
read requests over time. It is useful to avoid overflow situations when the resizer module is
programmed to work from memory to memory.
1286
Camera Image Signal Processor
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated