ADSP-2109 AD [Analog Devices], ADSP-2109 Datasheet - Page 23

• Manufacturer Part Number: ADSP-2109
• Description: Low Cost DSP Microcomputers
• Manufacturer: AD [Analog Devices]

REV. 0
TIMING PARAMETERS (ADSP-2104/ADSP-2109)
BUS REQUEST/GRANT
Parameter
Timing Requirement:
t
t
Switching Characteristic:
t
t
t
t
NOTES
1
Note: BG is asserted in the cycle after BR is recognized. No external synchronization circuit is needed when BR is generated as an asynchronous signal.
BH
BS
SD
SDB
SE
SEC
If BR meets the t
a pulse width greater than 10 ns.
BR Hold after CLKOUT High
BR Setup before CLKOUT Low
CLKOUT High to DMS,
PMS, BMS, RD, WR Disable
DMS, PMS, BMS, RD, WR
Disable to BG Low
BG High to DMS, PMS,
BMS, RD, WR Enable
DMS, PMS, BMS, RD, WR
Enable to CLKOUT High
BS
and t
BH
setup/hold requirements, it will be recognized in the current processor cycle; otherwise it is recognized in the following cycle. BR requires
PMS, DMS
CLKOUT
CLKOUT
BMS, RD
WR
BG
BR
1
1
t
SD
t
BH
Figure 21. Bus Request/Grant
t
BS
t
SDB
Min
17.5
32.5
0
0
2.5
20 MHz
–23–
Max
32.5
t
SE
t
ADSP-2104/ADSP-2109
SEC
Min
0.25t
0.25t
0
0
0.25t
CK
CK
CK
Dependency
Frequency
+ 5
+ 20
– 10
Max
0.25t
CK
+ 20
Unit
ns
ns
ns
ns
ns
ns