EMIF Registers
9-17
External Memory Interface
9.3.4
EMIF SDRAM Timing Register
The SDRAM timing register controls the refresh period in terms of CLKOUT2
cycles for the ’C6201/C6202/C6701 (half of the CPU clock rate), or in terms
of ECLKOUT cycles for the ’C6211/C6711. Optionally, the period field can
send an interrupt to the CPU. Thus, this counter can be used as a general-
purpose timer if SDRAM is not used by the system. The counter field can be
read by the CPU. When the counter reaches 0, it is automatically reloaded with
the period and an interrupt (SDINT) is sent to the interrupt selector. See section
9.4.3 for more information on SDRAM refresh.
Figure 9–12 and Table 9–6 describe the fields of the SDRAM timing register.
The ’C6211/C6711 can control the number of refreshes performed when the
refresh counter expires via the XRFR field. Up to four refreshes can be per-
formed when the refresh counter expires.
Figure 9–12. EMIF SDRAM Timing Register
31 26
25 24
23
12
11
0
Reserved
XRFR‡
COUNTER
PERIOD
R, +0000 00
R, +0
†
RW,+00
‡
R, +0000 1000 0000
†
R, +0101 1101 1100
‡
RW, +0000 1000 0000
†
RW, +0101 1101 1100
‡
† Applies to TMS320C6201/C6202/C6701
‡ Applies to TMS320C6211/C6711 only
Table 9–6. EMIF SDRAM Timing Register Field Descriptions
Field
Description
PERIOD
†Refresh period in CLKOUT2 cycles
‡Refresh period in ECLKOUT cycles
COUNTER
Current value of the refresh counter
XRFR‡
‡Extra refreshes: controls the number of refreshes per-
formed to SDRAM when the refresh counter expires.
† Applies to TMS320C6201/C6202/C6701
‡ Applies to TMS320C6211/C6711 only