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TMS380C26
NETWORK COMMPROCESSOR
SPWS010A–APRIL 1992–REVISED MARCH 1993
POST OFFICE BOX 1443
•
HOUSTON, TEXAS
77251–1443
75
PARAMETER MEASUREMENT INFORMATION
68xxx DIO read timing
NO.
PARAMETER
MIN
MAX
UNIT
255
Delay from SDTACK low to either SCS, SUDS, or SLDS high
15
ns
259†
Hold of SAD high-impedance after SUDS or SLDS low (see Note 21)
0
ns
260
Setup of SADH0–SADH7, SADL0–SADL7, SPH, and SPL valid before SDTACK low
0
ns
261†
Delay from SCS, SUDS, or SLDS high to SADH0–SADH7, SADL0–SADL7, SPH, and SPL
high-impedance (see Note 21)
35
ns
261a
Hold of output data valid after SUDS or SLDS no longer low (see Note 21)
0
ns
267
Setup of register address before SUDS or SLDS no longer high (see Note 21)
15
ns
268
Hold of register address valid after SUDS or SLDS no longer low (see Note 22)
0
ns
272
Setup of SRNW before SUDS or SLDS no longer high (see Note 21)
15
ns
273
Hold of SRNW after SUDS or SLDS high
0
ns
273a
Hold of SIACK high after SUDS or SLDS high
55
ns
275
Delay from SCS, SUDS, or SLDS high to SDTACK high (see Note 21)
35
ns
276‡
Delay from SDTACK low in the first DIO access to the SIF register to SDTACK low in the immediately fol-
lowing access to the SIF
4000
ns
279†
Delay from SUDS or SLDS high to SDTACK high impedance
65
ns
282a
Delay from SDBEN low to SDTACK low
35
ns
282R
Delay from SUDS or SLDS low to SDBEN low (see
TMS380 Second Generation Token-Ring User’s
Guide, SPWU005, subsection 3.4.1.1.1) provided the previous cycle completed
55
ns
283R
Delay from SUDS or SLDS high to SDBEN high (see Note 21)
35
ns
286
Pulse duration, SUDS or SLDS high between DIO accesses (see Note 21)
55
ns
† This specification is provided as an aid to board design.
‡ This specification has been characterized to meet stated value.
NOTES: 21. The “inactive” chip select is SIACK in DIO read and DIO write cycles, and SCS is the “inactive” chip select in interrupt acknowledge
cycles.
22. In 80x8x mode, SRAS may be used to strobe the values of SBHE, SRSX, SRS0–SRS2, and SCS. When used to do so, SRAS must
meet parameter 266a, and SBHE, SRS0–SRS2, and SCS must meet parameter 264. If SRAS is strapped high, then parameters
266a and 264 are irrelevant, and parameter 268 must be met.