MDDR Subsystem
Microsemi Proprietary UG0446 User Guide Revision 7.0
24
The SECDED bits are interlaced with the data bits, as listed in the following table.
When the controller detects a correctable SECDED error, it does the following:
1.
Generates an interrupt signal which can be monitored by reading the interrupt status register,
. The ECCINT interrupt is mapped to the group0 interrupt
signalMSS_INT_M2F[12] in SmartFusion2 or HPMS_INT_M2F[12] in IGLOO2 of the fabric interface
interrupt controller (FIIC).
2.
Sends the corrected data to the read requested MSS/HPMS FPGA fabric master as part of the read
data.
3.
Sends the SECDED error information to the
register.
4.
Performs a read-modify-write operation to correct the data present in the DRAM.
When the controller detects an uncorrectable error, it does the following:
1.
Generates an interrupt signal which can be monitored by reading the interrupt status register,
. The ECCINT interrupt is mapped to the group0 interrupt signal
MSS_INT_M2F[12] in SmartFusion2 or HPMS_INT_M2F[12] in IGLOO2 of the FIIC.
2.
Sends the data with error to the read requested MSS/HPMS FPGA fabric master as part of the read
data.
3.
Sends the SECDED error information to the
register.
The following
can be monitored for identifying the exact location of an error in the
DDR SDRAM.
1.
DDRC_LUE_ADDRESS_1_SR and DDRC_LUE_ADDRESS_2_SR give the row/bank/column
information of the SECDED unrecoverable error.
2.
DDRC_LCE_ADDRESS_1_SR and DDRC_LCE_ADDRESS_2_SR give the row/bank/column
information of the SECDED error correction.
3.
DDRC_LCB_NUMBER_SR indicates the location of the bit that caused the single-bit error in the
SECDED case (encoded value).
4.
DDRC_ECC_INT_SR indicates whether the SECDED interrupt is because of a single-bit error or
double-bit error. The interrupt can be cleared by writing zeros to
3.5.4.3.5
Power Saving Modes
The DDR controller can operate DDR memories in three power saving modes:
Precharge Power-Down (DDR2, DDR3, LPDDR1)
•
If power-down is enabled in the
System Builder MDDR configuration
or
= 1, the DDR controller automatically keeps DDR memory in
precharge power-down mode when the period specified by the power down entry time or
register has passed, while the controller is idle (except for
issuing refreshes).
•
The controller automatically performs the precharge power-down exit on any of the following
conditions:
•
A refresh cycle is required to any rank in the system.
•
The controller receives a new request from the core logic.
•
REG_DDRC_POWERDOWN_EN is set to 0.
Self Refresh (DDR2, DDR3, LPDDR1)
Table 11 •
SECDED DQ Lines at DDR
Mode
SECDED Data Pins
M2S/M2GL005/010/025
/060/090
M2S/M2GL150-FCV484
M2S/M2GL 050
(FCS325, VF400,
FG484)
M2S/M2GL 050
(FG896)
M2S/M2GL 150
(FC1152)
Full bus width
—
—
MDDR_DQ_ECC[3:0] MDDR_DQ_ECC[3:0]
Half bus width
MDDR_DQ_ECC[1:0]
MDDR_DQ_ECC[1:0] MDDR_DQ_ECC[1:0] MDDR_DQ_ECC[1:0]
Quarter bus width MDDR_DQ_ECC[0]
—
—
MDDR_DQ_ECC[0]