User's Manual

1323x-Modular Reference Board
1323x Development Hardware Reference Manual, Rev. 1.0
Freescale Semiconductor 3-13
3.3.3 1323x-MRB Onboard Peripheral Functions
The 1323x-MRB has two onboard peripheral functions to assist in implementing targeted applications.
NOTE
To use the peripherals, a minimum power supply voltage of 2.7 V must be
maintained.
3.3.3.1 2 Mbit Serial FLASH (SPI Interface)
Component U2 is an Atmel AT45DB021D 2 Mbit (256 kbyte) serial FLASH memory with SPI interface.
The memory is useful for over-the-air programming (OTAP) and for storage of non-volatile system data
or parameters. Figure 3-9 shows the memory circuit.
• Memory power supply is V_MEM (Header J9, Pin 1-2)
• Disabling the memory supply V_MEM may load the MC1323x SPI port through the U2 ESD
diodes
• Discrete pullup resistors for the SPI port are provided
• The SPI can be shared with another peripheral - an additional IO signal would be required as a chip
enable (CS or SS) for the peripheral. The normal SPI_SS and the second chip select should NOT
be active at the same time.
Figure 3-9. AT45DB021D 2 Mbit (256 kbyte) Serial FLASH memory
2MBit (256KB) FLASH
V_MEM
V_MEM V_MEMV_MEM
MRB-SPI_MISOMRB-SPI_MOSI
MRB-SPI_CLK
MRB-SPI_SS
R21
10K
R21
10K
R18
10K
R18
10K
U2
AT45DB021D
U2
AT45DB021D
SCK
2
VCC
6
WP
5
RESET
3
GND
7
CS
4
SI
1
SO
8
R17
10K
R17
10K
R22
10K
R22
10K