Sundance SMT6035 v.2.2 - Manual (Page 22)

Version 2.2 Page 22 of 39 SMT6035 User Manual
15.2 Control words
Control words form the basis of the HSC operation, and are used to
synchronize events between the host and the root DSP. The control word
mechanism employs Mailbox 1 as described in section 14.
In all data transfers between the host and the DSP, control words are used to
indicate the type of transfer as well as the data size. They ensure that both the
host and the root DSP can safely access shared memory resources.
The 32 bit value used with mailbox 1 is interpreted as a HSC_WORD.
typedef struct {
UINT32 Data :25; /* Data value */
UINT32 Fn : 4; /* Function code */
UINT32 Channel : 3; /* Channel selector */
} HSC_WORD;
It contains the following information:
• Data field
• Function (command).
• Channel number.
The function value specifies which function will be performed; it may also
contain status or return values. There are a total of 16 possible functions, with
the following 10 functions defined by default:
Value Define
Description
0 HSC_OK OK reply
1 HSC_Error Error reply
2 HSC_OpenHandler Host opens a handler
3 HSC_CloseHandler Host closes a handler
4 HSC_SramToHost DSP writes SRAM argument area
5 HSC_HostToSram DSP reads SRAM argument area
6 HSC_OpenPci Host sets up PCI memory
7 HSC_ClosePci Host releases PCI memory
8 HSC_PciToHost DSP write PCI memory space
9 HSC_HostToPci DSP read PCI memory space
User Manual - Version 2.2, 04/01/07; © Sundance Italia S.R.L.