Specifications

100 Élan™SC310 Microcontroller Data Sheet
PRELIMINARY
Notes:
Fast ROM cycles, see the Élan
TM
SC300 and Élan
TM
SC310 Devices’ ISA Bus Anomalies Application Note , order #20747.
1. This is the timing when ROMCS is qualified with MEMR or MEMW, (Bit 2 of the Miscellaneous 5 Register, Index B3h, = 0).
2. This is the timing when ROMCS is configured as an address decode, (Bit 2 of the Miscellaneous 5 Register, Index B3h, = 1).
These timings are based on default wait state settings, set for 3 wait states in bits 4 and 7 of the Command Delay Register, Index
60h, and required initial programming. These timings may be modified via the MMS Memory Wait State 1 Register, Index 62H,
and the Command Delay Register, Index 60H. (See the
Élan
TM
SC310 Microcontroller Programmer’s Reference Manual, order
#20665.
)
For Fast ROMCS (BIOS ROM) accesses, set bit 6 of Miscellaneous 5 Register, Index B3h. Bits 4 and 5 control wait states when
Fast ROMCS
is enabled. For 16-bit Fast ROMCS timings with the default wait state settings of 4 wait states, see Table 54. For
more information about
Table 52. BIOS ROM Read/Write 8 Bit Cycle (See Figure 41)
Symbol Parameter Description Notes
Preliminary
Units
Min Max
t1a SA stable to ROMCS
active 1 55 ns
t1b SA stable to ROMCS
active 2 5 ns
t2a SA hold from ROMCS
inactive (write) 1 50 ns
t2b SA hold from ROMCS
inactive (read) 1 0 ns
t3a ROMCS
pulse width (read) 1 390 ns
t3b ROMCS
pulse width (write) 1 335 ns
t4a MEMW
active to ROMCS active 1 2 ns
t4b MEMR
active to ROMCS active 1 1 ns
t5a ROMCS
hold from MEMW inactive 1 0 ns
t5b ROMCS
hold from MEMR inactive 1 0 ns
t6 RDDATA setup to command inactive 40 ns
t7 RDDATA hold from command inactive 0 ns
t8 WRDATA setup to command inactive 200 ns
t9 WRDATA hold from command inactive 50 ns
t10 DBUFOE
active from command 5 ns
t11a DBUFOE
hold from MEMW 50 ns
t11b DBUFOE
hold from MEMR –2 ns
t12 ENDIRH, ENDIRL setup before MEMR
50 ns
t13 ENDIRH, ENDIRL hold from MEMR
–4 ns
t14 ROMCS
active to command active 2 65 ns
t15 ROMCS
hold from SA 2 5 ns