80-0206-R Datasheet, PDF (14/49 Pages) List of Unclassifed Manufacturers – Speech Recognition Processor

RSC-4128
Data Sheet
GPIO during powerdown
GPIO should be put in input mode and a known state (e.g. light pull-up) whenever practical to conserve power and
not in conflict with their intended function, and especially in powerdown mode to achieve the specified minimum
supply current consumption.
Memory Addressing
The RSC4128 can address up to 2MBytes with a combination of 128Kbytes of default internal ROM and/or optional
external ROM, RAM or flash memories, without additional decoding circuitry. This is accomplished with 16 address
outputs, A[15:0], and up to 4 extended address outputs A[19:16]. There are two different memory spaces of up to
1MBbyte each: Constant/Code Space and Data Space. (“Constant” Space is referred to as “Const” space in
assembly and C-Data space in C) Data Space can be read or written. Constant/Code Space is typically read-only.
The RSC-4128 includes an external memory interface that allows connection with memory devices for storage of
speaker-dependent speech recognition templates, audio record/playback data storage, extended durations of
speech and music synthesis beyond the storage capabilities of on chip ROM, and code storage. Thirty-four (34)
pins are used to provide a parallel bus interface between the processor and external ROM, EPROM, SRAM, or
FLASH, for die and 100LQFP-packaged versions. An example of this parallel bus usage is provided in the
Reference Schematic 1-2. The RSC-4128 external memory interface has been improved for ATD-type memories.
The external address lines remain stable during instruction cycles that access internal RAM or ROM. The –RDR
and –RDF signals go high when not actively reading. The condition of the external data lines is weak pull-up when
not accessing the external bus. (See “DC Characteristics” section for bus electrical characteristics.)
One may also interface to serial memory devices for storage and retrieval of speech data, by using the serial
drivers for ROM, Flash, EEPROM, etc. provided in the FluentChip™ Technology Library. The serial memory option
is useful for applications of the RSC4128 packaged in a 64LQFP (which lacks the external parallel bus) for which
speech or music data exceed the storage capacity of on chip ROM. Using serial ROM, Flash or EEPROM may
result in a simpler, smaller PCB layout and lower overall system cost. The specific I/O used by the serial interface
are configurable. (See the “FluentChip™ Technology Library Manual” for more information). An example of the
optional use of external serial Flash is provided in Reference Schematic 1-1.
Constant/Code Space
When reading, Constant/Code Space can be either internal to the chip or external. Typical uses of this space are
for code storage, and SI recognition set and/or compressed speech constant data storage. When the –XM input
pin is held low, Constant/Code Space is external to the chip when reading and –RDR is the read strobe. When the
–XM pin is high, Constant/Code Space reads are always internal to the chip, and are limited to the physical size of
the internal ROM.
NOTE: Constant Space may be referred to as “Const Space” in assemblers and compilers.
When writing, –WRC is the write strobe regardless of the state of the –XM pin. Writing to Constant/Code Space
requires the MOVC instruction, which is limited to the first 128KBytes of Constant/Code Space.
When reading Constant/Code Space, an application can access up to 1MByte. However, only the first 128KBytes
can be used by the processor for program instructions (Code). The MOVC instruction can only read these first
128KBytes. These first 128KBytes are partitioned into 64Kbyte banks, called Code Bank 0 and Code Bank 1.
(NOTE: Code using both banks up to 128KBytes must provide “mirror” code in both banks for routines such as
Interrupt Service, etc, with protocols to track bank identity.) The MOVX instruction can read the full 1Mbyte.
However, the MOVC is more efficient for reading Constants within the current Code Bank.
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P/N 80-0206-R
© 2006 Sensory Inc.