Clocks - Altera cyclone V Technical Reference

cv_5v4
2016.10.28
Data Receive
• Data timeout—during a read-data transfer, if the data start bit is not received before the number of
clock cycles specified in the timeout register, the data path does the following action:
• Signals a data-timeout error to the BIU
• Terminates further data transfer
• Signals data transfer done to BIU
• Data SBE—during a 4-bit or 8-bit read-data transfer, if the all-bit data line does not have a start bit, the
data path signals a data SBE to the BIU and waits for a data timeout, after which it signals that the data
transfer is done.
• Data CRC error—during a read-data-block transfer, if the CRC-16 received does not match with the
internally generated CRC-16, the data path signals a data CRC error to the BIU and continues with the
data transfer.
• Data EBE—during a read-data transfer, if the end bit of the received data is not 1, the data path signals
an EBE to the BIU, terminates further data transfer, and signals to the BIU that the data transfer is
†
done.
• Data starvation due to FIFO buffer full—during a read data transmission and when the FIFO buffer
becomes full, the card clock stops. If the FIFO buffer remains full for a data-timeout number of clock
cycles, the data path signals a data starvation error to the BIU, by setting the data starvation host
timeout bit (
†
empty.

Clocks

Table 14-19: SD/MMC Controller Clocks
Clock Name
l4_mp_clk
sdmmc_clk
sdmmc_cclk_out
sdmmc_clk_divided
sdmmc_sample_clk
sdmmc_drv_clk
SD/MMC Controller
Send Feedback
†
†
†
†
) in register to 1, and the data path continues to wait for the FIFO buffer to
hto rintsts
Direction
In
In
Out
Internal
Internal
Internal
†
Clock for SD/MMC controller BIU
Clock for SD/MMC controller
Generated output clock for card
Divide-by-four clock of
sdmmc_clk
Phase-shifted clock of
sdmmc_clk_divided
sample the command and data from the card
Phase-shifted clock of
sdmmc_clk_divided
to drive command and data to the card to meet hold time
requirements
Data Receive
†
Description
used to
for controller
Altera Corporation
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