dsm2180f3 STMicroelectronics, dsm2180f3 Datasheet - Page 7

• Manufacturer Part Number: dsm2180f3
• Description: Dsm Digital Signal Processor System Memory For Analog Devices Adsp-218x Family 5v Supply
• Manufacturer: STMicroelectronics

ARCHITECTURAL OVERVIEW
Major functional blocks are shown in Figure 5.
DSP Address/Data/Control Interface
These DSP signals attach directly to the DSM in-
puts for a glueless connection. An 8-bit data con-
nection is formed and all 22 DSP address lines
can be decoded while the DSP operates in full
memory mode. DSP memory strobes;
and
respectively (no program memory access,
Flash Memory
The 1 Mbit (128K x 8) Flash memory is divided into
eight equally-sized 16K byte sectors that are indi-
vidually selectable through the Decode PLD. Each
Flash memory sector can be located at any ad-
dress as defined by the user with PSDsoft Ex-
press. The flexibility of the Decode PLD and Page
Register logic allow the DSP to access Flash
memory as Byte DMA (BDMA) or as external data
overlay memory across several memory pages.
BDMA transfers are good for initial bootloading
and for loading internal overlay memory at runt-
ime, but BDMA is not efficient writing to Flash
memory because Flash memory is unlocked, writ-
ten, and status is checked one byte at a time, re-
quiring an initialization of the BDMA channel for
each and every byte transfer. The DSM device al-
IOMS
are used for BDMA, data, & I/O access
BMS
PMS
,
DMS
).
,
lows the DSP to alternatively access Flash memo-
ry as data overlay memory (using
BMS
requires simpler code. Note: During a DSP data
access using the
of a 16-bit DSP data word is used.
DSM Flash memory sector size of 16K bytes
matches the DSP external Data Memory Overlay
window size of 16K locations (two 8K windows
when DMOVLAY register is used, see Analog De-
vices ADSP-218X data sheets). This alignment
provides convenient data management. Also,
each 16K byte sector can be loaded with contents
from different firmware or data files specified in
PSDsoft Express
Miscellaneous: The DSP can erase Flash memory
by individual sectors or the entire Flash memory
array may be erased at one time. The Flash mem-
ory automatically goes to standby between DSP
read or write accesses to conserve power. Maxi-
mum access times include sector decoding time.
Maximum erase cycles is 100K and data retention
is 15 years minimum. Flash memory, as well as
the entire DSM device may be programmed with
the JTAG ISP interface with no DSP involvement.
). Writing Flash memory this way is faster and
TM
DMS
.
strobe, only the upper byte
DMS
DSM2180F3
instead of
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