Texas Instruments OMAP36 Series, Technical Reference Manual

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Camera ISP Functional Description
Table 6-53. Camera ISP Circular Buffer Internal State After Reset (continued)
Quantity Description
CPUWx 0
FCOx CBUFFx_START
OFFSET0 0
OFSFET1 0
OFFSET2,3 0
LEVELy 0
6.4.10.3.2.2 Camera ISP Circular Buffer Access Identification
For each access to the virtual space, the CBUFF module first checks the address (ADDR) to classify the
transaction into one of the categories listed in
Table 6-54 .
Table 6-54. Camera ISP Circular Buffer Address Identification
ID Label Condition
0 CW_CBUFF0 CBUFFx_CTRL [0] ENABLE = 1 and
ADDR>=FCO0 and
AD
CBUFFx_WINDOWSIZE and
ADDR= CBUFFx_END (x = 0)
1 NW_CBUFF0 CBUFFx_CTRL [0] ENABLE=1 (x = 0) and
ADDR>=FCO0 + CBUFFx_WINDOWSIZE and
AD 2* CBUFFx_WINDOWSIZE and
ADDR= CBUFFx_END (x = 0)
2 CW_CBUFF1 CBUFFx_CTRL [0] ENABLE=1 and
ADDR>=FCO1 and
AD
CBUFFx_WINDOWSIZE and
ADDR= CBUFFx_END (x = 1)
3 NW_CBUFF1 CBUFFx_CTRL [0] ENABLE=1 and
ADDR>=FCO1 + CBUFFx_WINDOWSIZE and
AD 2* CBUFFx_WINDOWSIZE and
ADDR= CBUFFx_END (x = 1)
4 ERR_CBUFF0 CBUFFx_CTRL [0] ENABLE=1 and
ADDR>= CBUFFx_START and
ADDR= CBUFFx_END (x = 0)
5 ERR_CBUFF1 CBUFFx_CTRL [0] ENABLE=1 and
ADDR>= CBUFFx_START and
ADDR= CBUFFx_END (x = 1)
6 TRANSPARENT Always true
Lower IDs correspond to higher priorities in case multiple conditions are true. For example, when the
current virtual window of the circular buffer 0 is accessed, at least the tests for categories CW_CBUFF0
and ERR_CBUFF0 are true. The final category is CW_CBUFF0, because it has a higher priority.
Further processing depends on the category:
• TRANSPARENT: Accesses flow through the module without changing its internal state or any
translation.
• ERR_CBUFF0 and ERR_CBUFF1: The module goes into error state for the concerned buffer
(CBUFF0 or CBUFF1) and set the
CBUFF_IRQSTATUS [1] IRQ_CBUFF0_INVALID bit (or
CBUFF_IRQSTATUS [4] IRQ_CBUFF1_INVALID). When the module is in error state for CBUFFx, all
accesses to that buffer are cancelled. In other words, any access that has an address between
CBUFFx_START and CBUFFx_END (x = 0) is not transmitted to the interconnect. There are two ways
to leave the error state:
– Hardware reset
– Disable and re-enable the buffer (CBUFF0 or CBUFF1) in error state
Accesses outside of the virtual space from the circular buffer in error state are not affected.
• CW_CBUFF0, NW_CBUFF0, CW_CBUFF1 and NW_CBUFF1: The internal state is updated and
address translation is performed when the performed access type (read or write) is compatible with the
1241 SWPU177N – December 2009 – Revised November 2010 Camera Image Signal Processor
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