Sundance SMT6025 v.2.9 - Manual (Page 23)

Version 2.9 Page 23 of 45 SMT6025 User Manual
15.3 Reply word
A reply word is a 32-bit value transmitted from the host to the DSP using
mailbox 1 (see section 14). The value is interpreted as an
HSC_WORD
containing the following fields:
typedef struct {
UINT32 Data :25; // Data value
UINT32 Fn : 4; // Function code
UINT32 Channel : 3; // Channel selector
} HSC_WORD;
• Channel
The number of the high-speed-channel to be used.
• Fn
A code indicating the host’s response to the original command.
Value Function
Description
0 HSC_OK OK reply
1 HSC_Error Error reply
2..15 Reserved
• Data field
A 25 bit unsigned value containing optional error information.
15.4 Associated data
Some of the commands sent to the host have associated data that need to be
passed to the host. Similarly, the reply from the host may also include
associated data. This data is transmitted using either the carrier board’s SRAM
or the host memory.
15.4.1 Carrier board SRAM
Each HSC has an associated region of 64KB in the carrier board’s
SRAM, the argument area, to be used for transmitting associated data.
The DSP can read and write this memory using the global bus. The
carrier board’s SRAM is directly accessible in the host address space.
The
SMT6025 provides utility functions that allow the host to access the
argument area for each channel. Similarly, on the DSP side, 3L
Diamond © provides utility functions with which you can access the
SRAM argument area.
User Manual (QCF42); Version 2.9, 22/02/02; © Sundance Multiprocessor Technology Ltd. 2002