4-40
Memory Controller
4.7.2 ECC Erorrs and Interrupts
When an uncorrectable ECC error occurs, MCP_ N will be asserted for a minimum of two clock cycles if
the MCP enable bit (bit 1) of the PRIFOPT1 register is set. Correctable ECC errors will be reported to the
CPC700’s interrupt controller via IRQ 0. System software may seperately program the interrupt controller
to generate an interrupt to the processor based on this condition or not. See Section Chapter 10., “Interrupt
Controller” for more information.
4.7.3 ECC Timing
The effect of ECC on read and write accesses is shown in Table 35.:
Table 34. ECC Enable and Correction Bits
ECC Enable
ECCCF[1]
Bank Enable
ECCCF[8:15]
Correction Enable
ECCCF[16:23]
Notes
0
X
X
ECC globally disabled.
1
0
X
ECC globally enabled.
If a specific bank is disabled the Correction
Enable for that bank is a don’t care.
This setting is used for ROM
1
1
0
ECC globally enabled.
If a specific bank is enabled for ECC and dis-
abled for correction, checkbits will be ignored
and the data passed unchanged.
1
1
1
ECC globally enabled.
Bank is enabled for ECC and correction is
enabled.
This is the standard mode for ECC protected
memory.
Table 35. Effect of ECC on Timing
MCIF Transaction
Added Latency
Comment
ECC enabled:
Read Command
1 Clock
Read Data is latched in the ECC module prior to going
through ECC tree.
ECC enabled:
Burst or full single
beat write
None
Non-partial writes with ECC require no extra clock cycles
ECC enabled: Par-
tial Writes
Read L 1
Clock
On partial writes, a read-modify-write sequence is required to
correctly generate the write check bits.
ECC disabled: All
transactions
None
Note: If ECC is globally enabled, the timing on any particular
bank is the same, whether or not ECC for that bank is active.
Summary of Contents for CPC700
Page 10: ...Table of Contents x Table of Contents...
Page 16: ...Tables xvi List of Tables...
Page 28: ...1 12 CPC700 User s Manual Preliminary...
Page 72: ...3 36 Processor Interface...
Page 132: ...4 60 Memory Controller...
Page 184: ...5 52 PCI Interface...
Page 194: ...6 10 Clock Power Management and Reset...
Page 224: ...8 18 IIC...
Page 244: ...10 10 Interrupt Controller...
Page 246: ...I 11 2 JTAG...
Page 250: ...12 4 Processor Local Bus PLB...
Page 262: ...14 10 Register Summary...
Page 267: ...CPC700 User s Manual Preliminary...