User guide

C M M - 52259 J U N E 1 1 , 2 0 1 0
U S E R G U I D E
9
Internal SRAM
Internal, dual-ported, SRAM connects to the MCF52259’s internal high-speed local bus and
supports DMA, FEC, and USB access. The SRAM is partitioned into two physical memory ar-
rays allowing simultaneous access to arrays by the processor core and another bus master.
The user application can locate SRAM memory 64k boundary within the target device’s 4 GB
address space. The RAMBAR register value determines SRAM starting address location.
SRAM address space is undefined out of reset and must be configured by user application.
External FLASH
External FLASH memory consists of a Spansion, S25FL064, serial memory device connected
to the Queued Serial Peripheral Interface (QSPI) on the MCF52259. The QSPI module pro-
vides a serial peripheral interface with queued transfer capability allowing users to queue up to
16 transfers at once, eliminating CPU intervention between transfers. QSPI chip select,
QSPI_CS0*, is dedicated to external, on-board, FLASH memory transfers and may be discon-
nected by option jumper if necessary. Two additional QSPI chip-selects are available for use
with external, off-board serial devices connected to MCU_PORT. The QSPI module must be
enabled by user application before use.
External SRAM
External SRAM connects to the MCF52259 Mini-FlexBus external bus. The Mini-FlexBus is a
sub-set of the FlexBus found on other ColdFire MCU’s and interfaces to slave-only devices. In
default configurations, the CMM-52259 applies a Cypress, CY62128E device for external
memory. The external memory device footprint accepts memory devices within this family up
to 4Mb (512k x 8). Contact the factory for custom orders. Figure 2 below shows supported
memory devices and capacities.
Figure 2: Supported SRAM Devices
Device
Part Number
Size
Addr
bits
Org
Start
Address
CSAR0 +
End
Address
CSAR0 +
CY62128EV30LL
1Mb
A[16:0]
128k x 8
0x00000
0x1FFFF
CY62138FV30LL
2Mb
A[17:0]
256k x 8
0x00000
0x3FFFF
CY62148ESL
4Mb
A[18:0]
512k x 8
0x00000
0x7FFFF
The installed CY62128E provides 1Mbtye of storage organized as 128k words by 8 bits (128k
x 8). User programmable chip select, FB_CS0* is dedicated to external SRAM. The FB_CS0*
base address space is configured using Chip Select Address Register 0 (CSAR0). External
address space is not valid out of reset and must be configured by user application.
For Rev A boards, the FB_CS0* chip-select can not be disconnected from on-board external
memory. This chip-select may not be used for GPIO functions or for off-board, multiplexed
applications.