GPMC_FCLK
GPMC_CLK
WAIT
Valid address 0
Valid address 1
Data 0
Valid address 0
Valid address 1
Data 1
Data 1
CSONTIME
CSONTIME
CSRDOFFTIME
CSRDOFFTIME
ADVONTIME
ADVONTIME
ADVRDOFFTIME
ADVRDOFFTIME
OEONTIME
OEONTIME
OEOFFTIME
OEOFFTIME
RDCYCLETIME
RDCYCLETIME
CYCLE2CYCLEDELAY
nBE1/nBE0
nCS
nADV
nOE
DIR
OUT
OUT
OUT
IN
IN
A[27:17]
A[16:1]/D[15:0]
GPMC
•
Output enable signal OEn
–
OEn assertion indicates a read cycle.
–
OEn assertion time is controlled by the GPMC_CONFIG4_i[[3-0] OEONTIME field.
–
OEn deassertion time is controlled by the GPMC_CONFIG4_i[[12-8] OEOFFTIME field.
•
Read data is latched when RDACCESSTIME completes. Access time is defined in the
GPMC_CONFIG5_i[20-16] RDACCESSTIME field.
•
Direction signal DIR: DIR goes from OUT to IN at the same time that OEn is asserted.
•
The end of the access is defined by the GPMC_CONFIG5_i[4-0] RDCYCLETIME parameter.
In the GPMC, when a 16-bit wide device is attached to the controller, a 32-bit word write access is split
into two 16-bit word write accesses. For more information about GPMC access size and type adaptation,
see
. Between two successive accesses, if a OEn pulse is needed:
•
The GPMC_CONFIG6_i[[11-8] CYCLE2CYCLEDELAY field can be programmed with
GPMC_CONFIG6_i[[7] CYCLE2CYCLESAMECSEN enabled.
•
The CSWROFFTIME and CSONTIME parameters also allow a chip-select pulse, but this affects all
other types of access.
shows two asynchronous single-read accesses on an address/data-multiplexed devices.
Figure 7-13. Two Asynchronous Single Read Accesses on an Address/Data Multiplexed Device
(32-Bit Read Split Into 2 × 16-Bit Read)
282
Memory Subsystem
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated