Texas Instruments AM335 Series Technical Reference Manual

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7.1.3.9.1.3 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 7-44. Asynchronous NOR Formulas Description Table
Configuration
Unit Description
Parameter
A ns Pulse duration - GPMC_CSn low
B ns Delay time - GPMC_CSn valid to GPMC_ADVn_ALE invalid
C ns Delay time - GPMC_CSn valid to GPMC_OEn invalid (single read)
D ns Pulse duration - address bus valid - 2nd, 3rd and 4th accesses
E ns Delay time - GPMC_CSn valid to GPMC_WEn valid
F ns Delay time - GPMC_CSn valid to GPMC_WEn invalid
G ns Address invalid duration between 2 successive R/W accesses
H ns Setup time - read data valid before GPMC_OEn high
I ns Delay time - GPMC_CSn valid to GPMC_OEn invalid (burst read)
J ns Delay time - address bus valid to GPMC_CSn valid
Delay time - data bus valid to GPMC_CSn valid
Delay time - GPMC_BE0n_CLE/GPMC_BE1n valid to GPMC_CSn valid
K ns Delay time - GPMC_CSn valid to GPMC_ADVn_ALE valid
L ns Delay time - GPMC_CSn valid to GPMC_OEn valid
M ns Delay time - GPMC_CS valid to first data latching edge
N ns Pulse duration - GPMC_BE0n_CLE/GPMC_BE1n valid time
O ns Delay time - GPMC_CSn valid to GPMC_ADVn_ALE valid
The configuration parameters are calculated through the following formulas. Note that these formulas are
not exhaustive.
GPMC_CSn low pulse:
For single read: A = (CSRDOFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) *
GPMC_FCLK period
For burst read: A = (CSRDOFFTIME - CSONTIME + (N - 1) * PAGEBURSTACCESSTIME) *
(TIMEPARAGRANULARITY + 1) * GPMC_FCLK period, where N = page burst access number
For single write: A = (CSWROFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) *
GPMC_FCLK period
For burst write: A = (CSWROFFTIME - CSONTIME + (N - 1) * PAGEBURSTACCESSTIME) *
(TIMEPARAGRANULARITY + 1) * GPMC_FCLK period, where N = page burst access number
GPMC_CSn valid to GPMC_ADVn_ALE invalid delay:
For reading: B = ((ADVRDOFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) + 0.5 *
(ADVEXTRADELAY - CSEXTRADELAY)) * GPMC_FCLK period
For writing: B = ((ADVWROFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) + 0.5 *
(ADVEXTRADELAY - CSEXTRADELAY)) * GPMC_FCLK period
C = ((OEOFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) + 0.5 * (OEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
D = PAGEBURSTACCESSTIME * (TIMEPARAGRANULARITY + 1) * GPMC_FCLK period
E = ((WEONTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) + 0.5 * (WEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
F = ((WEOFFTIME - CSONTIME) * (TIMEPARAGRANULARITY + 1) + 0.5 * (WEEXTRADELAY -
CSEXTRADELAY)) * GPMC_FCLK period
G = CYCLE2CYCLEDELAY * GPMC_FCLK period
353
SPRUH73H–October 2011–Revised April 2013 Memory Subsystem
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Texas Instruments AM335 Series Specifications

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Brand	Texas Instruments
Model	AM335 Series
Category	Computer Hardware
Language	English