USBB17AP77016-XXX-B11 NEC Electronics, USBB17AP77016-XXX-B11 Datasheet - Page 36

• Manufacturer Part Number: USBB17AP77016-XXX-B11
• Description: DSP middleware(WMA (Windows Media Audio)decoder)
• Manufacturer: NEC Electronics

4.4
4.4.1
the DSP via a host interface. Input data is transmitted sequentially from the start of the data in 16-bit units. The
decode processing unit (number of samples) is the value indicated in Table 2-5 Recommended Output Buffer Size.
4.4.2
36
The sample program of the µ SAP77016-B11 is designed based on a system in which input data is transmitted to
An outline of the user-defined function sample source is shown below.
[Variables]
(1) FileCBGetData_fp variable
(2) read_ptr variable
(3) write_ptr variable
Sample Program Outline
This variable is used to manage the number of bytes of input data received via the host interface. In this
system, input data is received in 2-byte units, so this will always be an even number.
The value of this variable, x, also means that the offset from the start of the first input data received via the
host interface in the wmad_FileCBGetData function called this time is data of x and x + 1. Note that the value
of this variable is not “the value of argument R1 + R0 when the wmad_FileCBGetData function was previously
called”.
This variable is used to manage the position at which data starts to be read from the input data receive buffer
when data is set in the input buffer.
This variable is used to manage the position at which input data received via the host interface starts to be
written to the input data receive buffer.
Sample program
User-defined functions
read_ptr
write_ptr
host_in_buffer
Input data receive buffer
Figure 4-2. Configuration of Sample User-Defined Function Buffer
CHAPTER 4 SYSTEM EXAMPLE
128 words
User’s Manual U15683EJ1V0UM
input_buffer
Input buffer
64 words