PowerQUICC™ MPC8313E Reference Design Board (RDB), Rev. 4
14
Freescale Semiconductor
Board-Level Functions
2.5.3
LED/Status Buffers
The MPC8313E RDB has an 8-bit read/write buffer. The read buffer returns information on M66EN, board
revision, boot device (NOR or NAND), and SD card status. The write buffer controls eight LEDs on the
board for status or debug indication.
Figure 10
shows the hardware connection of the buffers.
Figure 10. LED/Status Buffers
2.6
I
2
C Interfaces
The MPC8313E has two I
2
C interfaces. On the MPC8313E RDB, I
2
C1 is used as master mode. It is
connected to the following three devices as shown in
Figure 11
.
•
Serial EEPROM M24256 at address 0x50.
•
Real-time clock DS1339U at address 0x68.
•
Thermal sensor LM75 at address 0x48.
It may also be connected to the DAC AD5301 at address 0x0C, whose optional nature is represented in
Figure 11
by the dashed line.
The connection of the I
2
C bus is shown in
Figure 11
. The M24256 serial EEPROM can be used to store
the reset configuration word of the MPC8313E, as well as to store the configuration registers’ values and
user program if the MPC8313E boot sequencer is enabled. By default, the EEPROM is not used and the
hard reset configuration words are loaded from local bus flash memory. For details about how to program
MPC8313E
eLBC
Controller
WE0
GPL2
LAD[0:7]
Buffer
LCS3
LCX373
LCX245
8x LEDs
Write Buffer
Read Buffer
SD_INSERT
SD_PROTECT
RSVD0
BOOT0
RSVD1
M66EN
REV0
REV1
LBD[0:7]
OE
