Motorola MSC8101 ADS User's Guide Page 80

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4-4 MSC8101 User’s Guide
Connecting External Memories and Memory-Mapped Devices
4.3 Connecting the Bus to the Flash Memory Interface
In most embedded systems, Flash memory is the standard way to store the non-volatile
bootstrap code for the system at power-up. In a DSP environment, typically at least one
device connects to flash to configure the system and then bootload real-time firmware
code into other devices. The MSC8101 supports such a Flash memory boot operation, as
follows:
1. Use Chip-Select 0 (
CS0) programmed as a GPCM.
2. Set timings to the most conservative timing mode (relaxed timing and 30 wait
states).
3. Use the Flash memory chip select (
CS0) to determine the 32-bit reset
configuration word that enables the many different MSC8101 modes during the
reset procedure.
4. When
HRESET is deasserted and code is fetched from memory as determined by
the Reset Vector pointer address.
Refer to Chapter 2, Reset Configuration and Boot for details on the reset configuration
and booting procedures. The following subsections present a typical MSC8101-to-flash
memory interconnection example, together with the primary GPCM register configuration
and timing assumptions.
4.3.1 GPCM Hardware Interconnection
The GPCM timing can interface with any industry-standard Flash memory device directly.
The example discussed here illustrates the use of an AMD AM29LV160D 1M bit × 16
flash memory. The chip select (
CS0), Output Enable (OE), and Write Enable (WE) signals
can connect directly to the Flash memory device, with appropriate register settings in
software (see Figure 4-2).
Figure 4-2. MSC8101-to-Flash Interconnect in Single-Master Bus Mode
MSC8101
GPCM
WE
OE
A[19-0]
CS0
WE
OE
A[12-31]
AM29LV160D
D[15-0]
D[0-15]
2MB Flash
60x bus
CE
Single-Master MSC8101 Bus mode
PowerPC
Memory
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