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10002367-02 PmT1 and PmE1 User’s Manual
4-1
Section 4
On-Card Memory Configuration
The PmT1 and PmE1 module provides one 32-pin flash socket, an EEPROM, and one RAM
configuration. Off-card memory may be accessed via the PMC/PCI interface.
SOCKETED FLASH
The PmT1 and PmE1 modules have a 32-pin PLCC socket for a byte-wide read-only flash. Up
to 512-kilobytes of flash may be installed. The socketed flash occupies physical address
space FFF0,0000-FFFF,FFFF
16
.
Note: To avoid damage, please use the proper tool to remove the PLCC device.
The MPC860P controls the access time for flash. The default power-up timing allows flash
with speeds of 200-nanoseconds or faster. We strongly suggest that you use the default
timing because of the inherent risks of optimizing timing for a specific configuration, and
because of the fact that flash may be cached.
Caution: The monitor resides within this socketed device (ROM address: 0x0 - 0x30000) and should
not be overwritten.
I
2
C EEPROM
Another memory device on the PmT1 and PmE1 is a 16-kilobit serial EEPROM. It is internally
organized as 1Kx16 and is accessed through the I
2
C interface pins on the MPC860P. The
EEPROM supports a sixteen-byte page write mode and a self-timed write cycle. It provides a
minimum endurance of 100,000 cycles and a minimum data retention of 100 years.
The I
2
C interface consists of the Serial Clock (SCL) and the Serial Data (SDA) lines, which are
controlled by bits in the PBDIR and PBDAT registers, and accessible with longword
read/write.
Table 4-1: I2C EEPROM Registers
Hex Address: Register Name: Bit: Access: Description:
FF00,0AB8 Port B Direction
(PBDIR)
27 R/W Set SDA as an input or an output.
0= Input
1= Output
FF00,0AC4 Port B Data
(PBDAT)
26 R/W I
2
C EEPROM Clock Line (SCL)
0= Drives SCL low
1= Drives SCL high
FF00,0AC4 PBDAT 27 W I
2
C EEPROM Line Driver (SDA)
0= Drives SDA low
1= Drives SDA high
FF00,0AC4 PBDAT 27 R I
2
C EEPROM Data on D0 (SDA)
!