TMS380C26

NETWORK COMMPROCESSOR

SPWS010A±APRIL 1992±REVISED MARCH 1993

PARAMETER MEASUREMENT INFORMATION

80x8x mode bus arbitration timing, SIF returns control

NO.

 

 

 

 

 

 

 

 

 

PARAMETER

 

MIN MAX

UNIT

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Delay from SBCLK low in I1 cycle to SADH0±SADH7, SADL0±SADL7, SPL, SPH,

 

and

 

 

 

 

 

220²

SRD,

SWR

 

35

ns

high-impedance

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

223b²

Delay from SBCLK low in I1 cycle to

 

high-impedance

 

45

ns

SBHE

 

224b

Delay from SBCLK low in cycle I2 to

 

 

high

 

25

ns

SOWN

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

224d

Delay from SBCLK low in cycle I2 to SDDIR high

 

30

ns

 

 

 

 

 

 

 

 

 

 

 

 

 

 

230

Delay from SBCLK high in cycle I1 to SHRQ low

 

25

ns

 

 

 

 

 

 

 

 

 

 

 

 

240²

Setup of

 

 

 

and

 

high-impedance before

 

no longer low

 

0

 

ns

SRD,

 

SWR,

SBHE

SOWN

 

 

²This specification has been characterized to meet stated value.

 

SIF Master

 

Bus Exchange

 

User Master

T3

T4

I1

I2

(T1)

(T2)

SBCLK

 

 

 

 

 

SHLDA

 

 

 

 

 

SIF Outputs:

 

230

 

 

 

 

 

 

 

 

SHRQ

 

 

 

 

 

(see Note A)

 

220

 

 

 

 

 

 

SRD, SWR

 

 

 

HI-Z

 

 

 

 

240

 

 

 

 

223b

 

 

 

SBHE

SIF

 

 

HI-Z

 

SADH0±SADH7,

220

 

240

 

 

 

 

 

 

 

SADL0±SADL7,

SIF

 

 

HI-Z

 

SPH, SPL

 

 

224d

 

 

 

 

 

 

 

WRITE

SDDIR

READ

224b

SOWN (see Note B)

NOTES: A. In 80x8x mode, the system interface deasserts SHRQ on the rising edge of SBCLK following the T4 state of the last system bus transfer it controls. In 68xxx mode, the system interface deasserts SBRQ on the rising edge of SBCLK in state T2 of the first system bus transfer it controls.

B. While the system interface DMA controls are active (i.e., SOWN is asserted), the SCS input is disabled.

Figure 35. 80x8x Mode Bus Arbitration Timing, SIF Returns Control

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73

77251±1443

 

Page 73
Image 73
Texas Instruments TMS380C26 specifications 80x8x mode bus arbitration timing, SIF returns control