Renesas SH7781 - Manual (Page 1235)

24. Multimedia Card Interface (MMCIF)
Rev.1.00 Jan. 10, 2008 Page 1205 of 1658
REJ09B0261-0100
24.3.15 Data Timeout Register (DTOUTR)
DTOUTR specifies the period to generate a data timeout. The 16-bit counter (DTOUTC) and a
prescaler, to which the peripheral bus does not have access, count the peripheral clock to monitor
the data timeout. The prescaler always counts the peripheral clock, and outputs a count pulse for
every 10,000 peripheral clock cycles. The initial value of DTOUTC is 0, and DTOUTC starts
counting the prescaler output from the start of the command sequence. DTOUTC is cleared when
the command sequence has ended, or when the command sequence has been aborted by setting the
CMDOFF bit to 1, after which the DTOUTC stops counting the prescaler output.
When the command sequence does not end, DTOUTC continues counting the prescaler output,
and enters the data timeout error states when the number of prescaler outputs reaches the number
specified in DTOUTR. When the DTERIE bit in INTCR1 is set to 1, the DTERI flag in INTSTR1
is set. As DTOUTC continues counting prescaler output, the DTERI flag setting condition is
repeatedly generated. To perform data timeout error handling, the command sequence should be
aborted by setting the CMDOFF bit to 1, and then the DTERI flag should be cleared to prevent
extra-interrupt generation.
For a command with data busy status, data timeout cannot be monitored since the command
sequence is terminated before entering the data busy state. Timeout in the data busy state should
be monitored by firmware.
DTOUTR
Bit:
Initial value:
R/W:
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
Bit Bit Name
Initial
Value R/W Description
15 to 0 DTOUTR All 1 R/W Data Timeout Time/10,000
Data timeout time: Peripheral clock cycle
× DTOUTR
setting value
Ч 10,000.