
HOLD/HOLDA Timing
126
April 2003 Revised June 2004
SPRS219D
8
HOLD/HOLDA Timing
Table 81. Timing Requirements for the HOLD/HOLDA Cycles for EMIFA Module
(see Figure 81)
NO.
500
600
UNIT
MIN
MAX
MIN
MAX
3
th(HOLDAL-HOLDL)
Hold time, HOLD low after HOLDA low
E
E
ns
E = the EMIF input clock (AECLKIN, CPU/4 clock, or CPU/6 clock) period in ns for EMIFA.
Table 82. Switching Characteristics Over Recommended Operating Conditions for the HOLD/HOLDA
Cycles for EMIFA Module
§
(see Figure 81)
NO.
PARAMETER
500
600
UNIT
MIN
MAX
MIN
MAX
1
td(HOLDL-EMHZ)
td(EMHZ-HOLDAL)
td(HOLDH-EMLZ)
td(EMLZ-HOLDAH)
td(HOLDL-EKOHZ)
td(HOLDH-EKOLZ)
E = the EMIF input clock (AECLKIN, CPU/4 clock, or CPU/6 clock) period in ns for EMIFA.
EMIFA Bus consists of: ACE[3:0], ABE[7:0], AED[63:0], AEA[22:3], AARE/ASDCAS/ASADS/ASRE, AAOE/ASDRAS/ASOE, and
AAWE/ASDWE/ASWE
,
ASDCKE, ASOE3, and APDT.
§The EKxHZ bits in the EMIF Global Control register (GBLCTL) determine the state of the AECLKOUTx signals during HOLDA. If EKxHZ = 0,
AECLKOUTx continues clocking during Hold mode. If EKxHZ = 1, AECLKOUTx goes to high impedance during Hold mode, as shown in
Figure 81.
All pending EMIF transactions are allowed to complete before HOLDA is asserted. If no bus transactions are occurring, then the minimum delay
time can be achieved. Also, bus hold can be indefinitely delayed by setting NOHOLD = 1.
Delay time, HOLD low to EMIFA Bus high impedance
2E
2E
ns
2
Delay time, EMIF Bus high impedance to HOLDA low
0
2E
0
2E
ns
4
Delay time, HOLD high to EMIF Bus low impedance
2E
7E
2E
7E
ns
5
Delay time, EMIFA Bus low impedance to HOLDA high
0
2E
0
2E
ns
6
Delay time, HOLD low to AECLKOUTx high impedance
2E
2E
ns
7
Delay time, HOLD high to AECLKOUTx low impedance
2E
7E
2E
7E
ns
HOLD
HOLDA
EMIF Bus
DSP Owns Bus
External Requestor
Owns Bus
DSP Owns Bus
C64x
C64x
1
3
2
5
4
AECLKOUTx
(EKxHZ = 0)
AECLKOUTx
(EKxHZ = 1)
6
7
EMIFA Bus consists of: ACE[3:0], ABE[7:0], AED[63:0], AEA[22:3], AARE/ASDCAS/ASADS/ASRE, AAOE/ASDRAS/ASOE, and
AAWE/ASDWE/ASWE, ASDCKE, ASOE3, and APDT.
The EKxHZ bits in the EMIF Global Control register (GBLCTL) determine the state of the AECLKOUTx signals during HOLDA. If EKxHZ = 0,
AECLKOUTx continues clocking during Hold mode. If EKxHZ = 1, AECLKOUTx goes to high impedance during Hold mode, as shown in
Figure 81.
Figure 81. HOLD/HOLDA Timing for EMIFA