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P5040/P5020 Reference Design Board User Guide, Rev. 0
Freescale Semiconductor
29
Architecture
This table summarizes local bus chip select routing.
5.1.16.1
Address Latch/Data Transceivers
TI device SN74ALVTH32373ZKER provides address latch while the On Semiconductor device
MC74LCX16245DTG provides dual data transceivers.
A transceiver latch enable (LE) input signal is driven by a P5040/P3041/P5020 LALE output signal.
•
When LE is taken low, transceiver Q outputs are latched at input-set levels.
•
Latched LA[0:26] + LA[27:31] comes directly from the CPU to build a full LA[0:31] address bus.
•
The data bus was built with data buffers controlled by the CPU_LBCTL signal.
•
D[0:26] is muxed with address.
•
D[27:31] is only defined as data.
5.1.16.2
NOR FLASH
Spansion in-socket NOR FLASH memory (S29GL01GP11TFIR1) has 128 MB and a 16-bit data width.
The FLASH is controlled by the GPCM local bus. Bus data is obtained from the data transceiver. For
address information, see
Section 5.1.16.1, “Address Latch/Data Transceivers
FLASH functioning is as follows:
•
Local bus LOE controls FLASH OE while LWE0 controls the FLASH WE signal.
•
FLASH RY/BY output signal detects the completion of FLASH programming or erasure. The
signal is connected to the P5040/P5020 IRQ5 interrupt line.
Table 16. Local Bus Chip select Mapping
FLASH Selection
cfg_lbmap
1
[0:3]
1
cfg_lbmap[0:3] are user configuration DIP-switches.
NOR
FLASH
NAND
FLASH
PromJet
ngPIXIS
Description
0000
LCS0
LCS[2,4:6]
LCS1
LCS3
Boot from NOR FLASH region #0
0001
Boot from NOR FLASH region #1
0010
Boot from NOR FLASH region #2
0011
Boot from NOR FLASH region #3
0100
Boot from NOR FLASH region #4
0101
Boot from NOR FLASH region #5
0110
Boot from NOR FLASH region #6
0111
Boot from NOR FLASH region #7
1000
LCS1
LCS[2,4:6]
LCS0
—
Boot from PromJet & NOR FLASH unbanked.
1001
LCS2
LCS[0,4:6]
LCS1
—
Boot from NAND & NOR FLASH unbanked.
1010–1111
Invalid