Serial Boot Facility Signals - Freescale Semiconductor MCF52277 Reference Manual

Signal Name
Column Address Strobe
Row Address Strobe
SDR Data Strobe
Write Enable
2.3.6

Serial Boot Facility Signals

Signal Name
Chip Select
Clock
Data In
Data Out
2.3.7 External Interrupt Signals
Signal Name
External Interrupts
2.3.8 DMA Signals
Signal Name
DMA Request
DMA Acknowledge
Freescale Semiconductor
Table 2-7. SDRAM Controller Signals (continued)
Abbreviation
SD_CAS SDRAM column address strobe.
SD_RAS SDRAM row address strobe.
SD_SDRDQS Generated by the memory controller in SDR mode, to mimic the DQS
signal generated by DDR memories during reads. It is routed out and
connected back to SD_DQS inputs.
SD_WE Indicates direction of data transfer on bus for SDRAM accesses. A
logic 1 indicates a read from a slave device and a logic 0 indicates a
write to a slave device.
Table 2-8. SBF Signals
Abbreviation
SBF_CS Chip select used to access external SPI memory.
SBF_CK 25 MHz clock source for external SPI memory.
SBF_DI Data being driven by SPI memory.
SBF_DO Data out to SPI memory. SBF uses this output solely for the purpose
of issuing the SPI memory
to SPI memory.
Table 2-9. External Interrupt Signals
Abbreviation
IRQ[7,4,1] External interrupt sources.
Table 2-10. DMA Signals
Abbreviation
DREQ0 Asserted by an external device to request a DMA transfer.
DACK0 Asserted by processor to indicate DMA request has been recognized.
MCF52277 Reference Manual, Rev. 1
Function
Function
command. SBF does not write data
READ
Function
Function
Signal Descriptions
I/O
O
O
O
O
I/O
O
O
I
O
I/O
I
I/O
I
O
2-9