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Camera ISP Basic Programming Model
6.5.10.6 Camera ISP Histogram Summary of Constraints
The following is a list of register configuration constraints to adhere to when programming the histogram. It
can be used as a quick checklist. More detailed register setting constraints can be found in the individual
register descriptions.
•
The input address and line offset must be on 32-byte boundaries.
•
A region dimension of 1 (horizontal or vertical or both) is not allowed.
6.5.11 Programming the Central-Resource SBL
This section discusses issues related to the software control of the central-resource SBL. It lists which
registers are required to be programmed in different modes, describes how to check the status of the
central resource SBL overflow bits, and enumerates programming constraints.
The central-resource SBL controls data interactions between the camera ISP modules and the interface to
memory. A small number of registers configure maximum data-read bandwidth in memory-to-memory
operations.
6.5.11.1 Camera ISP Central-Resource SBL Setup/Initialization
This section discusses the configuration of the central-resource SBL required before image processing
can begin.
6.5.11.1.1 Camera ISP Central-Resource SBLReset Behavior
On hardware reset of the camera ISP, all registers in the SBL are reset to their reset values.
6.5.11.1.2 Camera ISP Central-Resource SBLRegister Setup
Before enabling any of the camera ISP modules, the hardware must be correctly configured through
register writes to the camera ISP registers. If the preview engine, resizer, or the histogram is reading from
memory, the
register must be programmed. The values programmed in each of the
three fields (PRV_EXP, RSZ_EXP, HIST_EXP) determines the number of clock cycles required to allow
two consecutive read requests from the module.
6.5.11.2 Camera ISP Central-Resource SBL Enable/Disable Hardware
The central-resource SBL functionality is always enabled, unless the PRCM idles the clocks to the camera
ISP.
6.5.11.3 Camera ISP Central-Resource SBL Event and Status Checking
The SBL generates one interrupt for the write buffer overflow events listed below. Software must check
which overflow event has raised the interrupt request, by reading the
register.
See
.
Table 6-77. Camera ISP Central-Resource SBL Write-Buffer Overflow Events
Bit
Event Description
[26] CSI1_CCP2B_CSI2C_WBL_OVF
CSI1/ CCP2B or CSI2C write-buffer memory overflow
[25] CSI2A_WBL_OVF
CSI2A write-buffer memory overflow
1295
SWPU177N – December 2009 – Revised November 2010
Camera Image Signal Processor
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