System Integration Module (SIM60)
MOTOROLA
MC68360 USER’S MANUAL
6-69
controller may sample TS with a one-clock-phase delay. This will delay the assertion of
the CS or RAS in the MC68EC040 memory cycle by one clock phase. It will delay the rest
of the bus cycle by one clock (effectively adding one extra clock cycle per bus cycle).
NOTE
In general, the user determines whether this bit must be set be-
fore to selecting the WBT40 and TCYC bits.
0 = Do not sample TS.
1 = Sample TS prior to using it.
NCS—No CPU Space
This attribute specifies whether the CS/RAS signal will assert on a CPU space access cy-
cle. If both supervisor data and program accesses are desired, while ignoring CPU space
accesses, then this bit should be set. (Note that an interrupt acknowledge cycle is a CPU
space access, but a user or supervisor read/write cycle is not.) A CPU space access has
the function code value 0111.
0 = Assert CS/RAS on CPU space accesses (default).
1 = Suppress CS/RAS on CPU space accesses.
NOTE
In default state, user should program the FC3-FC0 in both the
Option Registers and Base Registers so that CS/RAS will not
get asserted in an undesirable address range.
GAMX—Global Address Mux Enable
This attribute determines whether the QUICC will provide internal address multiplexing for
DRAM banks. If not, the address multiplexing must be provided externally, with the
QUICC’s AMUX pin being used to control the multiplexers. AMUX is high to signify the
row, low to signify the column address, and then negated (high) at the end of the DRAM
bus cycle.
There are two situations in which the user may wish to provide address multiplexing ex-
ternally. First, external multiplexers are required when an external master exists in the
system and that external master needs to access the DRAM. Second, using external ad-
dress multiplexing causes the clock to address valid timing as slightly accelerated, which
may be beneficial in certain high-performance situations.
0 = Disable internal address multiplexing for all DRAM banks.
1 = Enable internal address multiplexing for all DRAM banks.
Bits 4–0—Reserved
6.13.2 Memory Controller Status Register (MSTAT)
The MSTAT register reports memory controller error information to the user. These bits are
set, regardless of whether an internal or external master originated the cycle. Bits are reset
by writing a one to that bit; writing a zero has no effect. The register may be read at any time
and is cleared by reset. No interrupts are generated from this register; however, an internal