Specifications

Data Structures
1.6 Control Register Access Mailbox Header (CRAMH)
Figure 1–8 Control Register Access Mailbox Header (CRAMH)
CRAMH$L_FLINK 0
CRAMH$L_BLINK 4
CRAMH$W_SIZECRAMH$B_TYPECRAMH$B_SUBTYPE 8
CRAMH$L_MAX 12
CRAMH$Q_PA_BASE 16
CRAMH$L_AVAIL 24
CRAMH$B_MAP (64 bytes) 28
Unused (36 bytes) 92
*A read-only field
Table 1–7 Contents of the Control Register Access Mailbox Header
Field Name Contents
CRAMH$L_FLINK Forward link. This link points to the CRAMH for the next group of
CRAMs.
CRAMH$L_BLINK Backward link. This link points to the CRAMH for the previous group of
CRAMs.
CRAMH$W_SIZE Structure size in bytes. The CRAMH structure is the same size as a CRAM
and takes the first CRAM slot in a page of CRAMs.
CRAMH$B_TYPE Structure type. Set to DYN$C_MISC when the CRAMH is allocated.
CRAMH$B_SUBTYPE Structure subtype. Set to DYN$C_CRAMH when the CRAMH is allocated.
CRAMH$L_MAX Maximum number of CRAMs linked to this CRAMH.
CRAMH$Q_PA_BASE Base physical address of this block of CRAMs.
CRAMH$L_AVAIL Total number of mailboxes available in this block.
CRAMH$B_MAP Usage bitmap. If a bit is set, its corresponding CRAM is available. Up to
64KB of CRAMs can be mapped.
1–25