Asynchronous Memory Timing - Texas Instruments TMS320C6712D User Manual

TMS320C6712D
FLOATING POINT DIGITAL SIGNAL PROCESSOR
SPRS293A − OCTOBER 2005 − REVISED NOVEMBER 2005
timing requirements for asynchronous memory cycles
NO. NO.
3 t su(EDV-AREH) Setup time, EDx valid before ARE high
4 t h(AREH-EDV) Hold time, EDx valid after ARE high
6 t su(ARDY-EKOH) Setup time, ARDY valid before ECLKOUT high
7 t h(EKOH-ARDY) Hold time, ARDY valid after ECLKOUT high
† To ensure data setup time, simply program the strobe width wide enough. ARDY is internally synchronized. The ARDY signal is recognized in
the cycle for which the setup and hold time is met. To use ARDY as an asynchronous input, the pulse width of the ARDY signal should be wide
enough (e.g., pulse width = 2E) to ensure setup and hold time is met.
‡ RS = Read setup, RST = Read strobe, RH = Read hold, WS = Write setup, WST = Write strobe, WH = Write hold. These parameters are
programmed via the EMIF CE space control registers.
switching characteristics over recommended operating conditions for asynchronous memory
द
cycles (see Figure 26−Figure 27)
NO. NO.
1 t osu(SELV-AREL) Output setup time, select signals valid to ARE low
Output hold time, ARE high to select signals
2 t oh(AREH-SELIV)
invalid
5 t d(EKOH-AREV) Delay time, ECLKOUT high to ARE valid
8 t osu(SELV-AWEL) Output setup time, select signals valid to AWE low
9 t oh(AWEH-SELIV) Output hold time, AWE high to select signals and EDx invalid
10 t d(EKOH-AWEV) Delay time, ECLKOUT high to AWE valid
11 t osu(EDV-AWEL) Output setup time, ED valid to AWE low
‡ RS = Read setup, RST = Read strobe, RH = Read hold, WS = Write setup, WST = Write strobe, WH = Write hold. These parameters are
programmed via the EMIF CE space control registers.
§ E = ECLKOUT period in ns
¶ Select signals include: CE[3:0], BE[1:0], EA[21:2], and AOE.
70

ASYNCHRONOUS MEMORY TIMING

PARAMETER PARAMETER
•
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
†‡
(see Figure 26−Figure 27)
RS*E − 1.7
RH*E − 1.7
WS*E − 1.7
WH*E − 1.7
(WS−1)*E −
−150
UNIT UNIT
MIN MAX
6.5 ns
1 ns
3 ns
2.3 ns
−150
UNIT UNIT
MIN MAX
ns
ns
1.5 7 ns
ns
ns
1.5 7 ns
ns
1.7