SAA7715 Datasheet, PDF (16/36 Pages) NXP Semiconductors – Digital Signal Processor

Philips Semiconductors
Digital Signal Processor
Preliminary specification
SAA7715H
9.5 Program RAM
The SAA7715 has a 1.5 kbyte PRAM to store the DSP
instruction code into. Also a 2 kbyte PROM is on-chip
available and can be accessed (memory mapped) without
the need of selecting the PROM or PRAM. The DSP
instruction code can be downloaded into the PRAM via the
I²C-bus. The write and read cycle are shown in Figs 5
and 6 respectively.
The DSP has an instruction word width of 32 bits which
means that this space should be accessed with 4 bytes in
consecutive order and does have the auto-increment
function.
9.6 Data word alignment
It is possible to transfer data via the I²C-bus to a
destination where it can have different data word length.
Those destinations with data word are shown in Table 7.
Table 7 Data word alignment
SOURCE
I²C-bus
I²C-bus
I²C-bus
I²C-bus
I²C-bus
DESTINATION
DSP-PRAM
DSP and general control
I²C-bus registers
DSP-XRAM
DSP-YRAM
DATA WORD
MBBB BBBB BBBB BBBB BBBB BBBB BBBB BBBL
MBBB BBBB BBBB BBBB BBBB BBBL
MBBB BBBB BBBB BBBB BBBB BBBL
MBBB BBBB BBBB BBBB BBBB BBBL
XXXX MBBB BBBB BBBL
BYTES
(NUMBER)
4
3
3
3
2
2001 May 07
16