
SDRAM Controller (SDRAMC)
Freescale Semiconductor
18-5
18.3
Interface Recommendations
18.3.1
Supported Memory Configurations
The SDRAM controller supports up to 14 row addresses and up to (13 in 16-bit bus mode) column
addresses. However, the maximum row and column addresses are not simultaneously supported. The
number of row and column addresses must be less than or equal to 24 (25 in 16-bit bus mode). In addition
to row/column address lines, there are always two row bank address bits. Therefore, the greatest possible
address space accessed using a single chip select is 2
26
x 32 bit (2
27
x 16 bit) or 256 MBytes.
SD_DQM[3:0]
O
Output mask signal for write data. During reads, SD_DQM may be driven high, low, or floating. The address
correspondence:
SD_DQM3 - SD_D[31:24]
SD_DQM2 - SD_D[23:16]
SD_DQM1 - SD_D[15:8]
SD_DQM0 - SD_D[7:0]
State
Meaning
Asserted — Data is written to SDRAM
Negation — Data is masked
Timing
Assertion/Negation — Occurs on crossing of SD_CLK and SD_CLK.
SD_DQS[3:2]
I/O Data strobes that indicate valid read/write data. (Edge-aligned with read data, centered with write data.)
The DQS frequency equals the memory clock frequency. Data is normally 1/4 memory clock period after a
DQS transition. For DDR operation, there is data following each DQS edge (rising and falling); for SDR
operation, valid data follows the rising edges only. The address correspondence:
SD_DQS3 - SD_D[31:24]
SD_DQS2 - SD_D[23:16]
Note: If a read is attempted from a DDR SDRAM chip select when there is no memory to respond with the
appropriate SD_DQS pulses, the bus cycle hangs. Because there is no high level bus monitor on the
device, a reset is the only way to exit this error condition.
State
Meaning
Asserted — Similar to a clock signal, the edges are more important than being asserted or
negated.
High impedance — Depending on the SDCFG1[OE_RULE] bit, the SD_DQS can be in high
impedance until a write is occurring or only when a read is occurring.
Timing
Assertion/Negation — Occurs on crossing of SD_CLK and SD_CLK.
SD_SDRDQS
O
SDR data strobe. Generated by the memory controller in SDR mode, to mimic the DQS generated by DDR
memories during reads. It should be routed out and connected back to the SD_DQS inputs.
State
Meaning
Asserted— Similar to a clock signal, the edges are more important than being asserted or
negated.
Timing
Assertion/Negation—Occurs on crossing of SD_CLK and SD_CLK.
SD_WE
O
Command input. Along with SD_CS, SD_CAS, and SD_RAS defines the current command.
State
Meaning
Please see
for SDRAM commands.
Timing
Assertion/Negation— Occurs synchronously with SD_CLK.
Table 18-1. SDRAM Interface—Detailed Signal Descriptions (continued)
Signal
I/O
Description
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...