Preliminary
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Basic Programming Model
5.3.6.1.3 Asynchronous NOR Flash Timing Parameters Formulas
This section lists all formulas to use in order to calculate asynchronous NOR timing parameters. This is
the case when [11-10] DEVICETYPE = 0x0 and when READTYPE or WRITETYPE are set to
asynchronous mode.
Table 5-44. Asynchronous NOR Formulas Description Table
Configuration
Unit
Description
Parameter
A
ns
Pulse duration - GPMC_CS low
B
ns
Delay time - GPMC_CS valid to GPMC_ADV_ALE invalid
C
ns
Delay time - GPMC_CS valid to GPMC_OE invalid (single read)
D
ns
Pulse duration - address bus valid - 2nd, 3rd and 4th accesses
E
ns
Delay time - GPMC_CS valid to GPMC_WE valid
F
ns
Delay time - GPMC_CS valid to GPMC_WE invalid
G
ns
Address invalid duration between 2 successive R/W accesses
H
ns
Setup time - read data valid before GPMC_OE high
I
ns
Delay time - GPMC_CS valid to GPMC_OE invalid (burst read)
J
ns
Delay time - address bus valid to GPMC_CS valid
Delay time - data bus valid to GPMC_CS valid
Delay time - GPMC_BE0_CLE/GPMC_BE1 valid to GPMC_CS valid
K
ns
Delay time - GPMC_CS valid to GPMC_ADV_ALE valid
L
ns
Delay time - GPMC_CS valid to GPMC_OE valid
M
ns
Delay time - GPMC_CS valid to first data latching edge
N
ns
Pulse duration - GPMC_BE0_CLE/GPMC_BE1 valid time
O
ns
Delay time - GPMC_CS valid to GPMC_ADV_ALE valid
The configuration parameters are calculated through the following formulas. Note that these formulas
are not exhaustive.
GPMC_CS low pulse:
For single read: A = (CSRDOFFTIME - CSONTIME) * (TIMEPARAGRANU 1) *
GPMC_FCLK period
For burst read: A = (CSRDOFFTIME - CS (N - 1) * PAGEBURSTACCESSTIME) *
(TIMEPARAGRANU 1) * GPMC_FCLK period, where N = page burst access number
For single write: A = (CSWROFFTIME - CSONTIME) * (TIMEPARAGRANU 1) *
GPMC_FCLK period
For burst write: A = (CSWROFFTIME - CS (N - 1) * PAGEBURSTACCESSTIME) *
(TIMEPARAGRANU 1) * GPMC_FCLK period, where N = page burst access number
GPMC_CS valid to GPMC_ADV_ALE invalid delay:
For reading: B = ((ADVRDOFFTIME - CSONTIME) * (TIMEPARAGRANU 1) + 0.5 *
(ADVEXTRADELAY - CSEXTRADELAY)) * GPMC_FCLK period
For writing: B = ((ADVWROFFTIME - CSONTIME) * (TIMEPARAGRANU 1) + 0.5 *
(ADVEXTRADELAY - CSEXTRADELAY)) * GPMC_FCLK period
C = ((OEOFFTIME - CSONTIME) * (TIMEPARAGRANU 1) + 0.5 * (OEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
D = PAGEBURSTACCESSTIME * (TIMEPARAGRANU 1) * GPMC_FCLK period
E = ((WEONTIME - CSONTIME) * (TIMEPARAGRANU 1) + 0.5 * (WEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
F = ((WEOFFTIME - CSONTIME) * (TIMEPARAGRANU 1) + 0.5 * (WEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
G = CYCLE2CYCLEDELAY * GPMC_FCLK period
649
SPRUGX9 – 15 April 2011
General-Purpose Memory Controller (GPMC)
© 2011, Texas Instruments Incorporated