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On-Card Memory Configuration: On-card DRAM
PmT1 and PmE1 User’s Manual 10002367-02
4-2
I
2
C EEPROM Operation
The I
2
C EEPROM supports a bidirectional bus-oriented protocol. The protocol defines any
device that sends data onto the bus as a transmitter and the receiving device as the receiver.
The device controlling the transfer is the CPU, and the I
2
C EEPROM being controlled is the
slave. The CPU always initiates data transfers and provides the clock for both transmit and
receive operations.
Initialization software for the I
2
C EEPROM should issue a start condition immediately fol-
lowed by a stop condition to reset EEPROM to a known state, since the chip maintains its
state even between power-ups.
Emerson Memory Map
The following memory map convention has been established by Emerson for data storage
within the I
2
C EEPROM. This map allows various operating systems to store their boot
parameters without affecting each other.
Table 4-2: I
2
C EEPROM Memory Map
ON-CARD DRAM
The PmT1 and PmE1 support 16-megabyte DRAM configuration four bytes wide, for data
storage. On-card RAM occupies physical addresses starting at 0000,0000
16
.
Note: All accesses to on-card DRAM must be aligned to natural boundaries. For example, byte accesses must be
aligned to byte boundaries, word accesses to word boundaries, and long-word accesses to long-word bound-
aries.
The DRAM is controlled by the MPC860P DRAM controller. The controller may be pro-
grammed for most memory sizes and speeds, block sizes from 32-kilobytes to 4-gigabytes,
and write protection.
In addition to the basic DRAM control functions the MPC860P chip provides several addi-
tional DRAM-related functions. Performance enhancing features include: programmable
delay insertion for controlling RAS recovery time, RAS low time, CAS setup before RAS time,
row address hold time, CAS recovery time, CAS pulse width, CAS access time, and address
access time.
Hex Byte Offset: Description:
400—7FF User nonvolatile data storage
300—3FF Reserved for the operating system
000—2FF Reserved for the monitor