TC1784
LMB External Bus Unit
User´s Manual
12-42
V1.1, 2011-05
EBUT13L-A, V1.16
rising edge of EBU_CLK to decide whether to prolong the Command Phase or to start
the next phase.
shows an example of WAIT used in Synchronous Mode.
Note: Due to the one-cycle delay in Synchronous Mode between the sampling of the
WAIT input and its evaluation by the EBU, the Command Phase must always be
programmed to be at least one EBU_CLK cycle (via EBU_BUSAPx.WAITRDC or
EBU_BUSAPx.WAITWRC) in this mode.
When programmed for asynchronous operation, WAIT is also sampled at each rising
edge of EBU_CLK during the Command Phase. However, an extra synchronization
cycle is inserted prior to the use of the sampled value. This means that the sampled
value is not used until the second following rising edge of EBU_CLK.
shows an example of WAIT used in Asynchronous Mode.
Note: Due to the two-cycle delay in Asynchronous Mode between the sampling of the
WAIT input and its evaluation by the EBU, the Command Phase must always be
programmed to be at least two EBU_CLK cycles (via EBU_BUSAPx.WAITRDC or
EBU_BUSAP.WAITWRC) in this mode.
shows an example of the extension of the Command Phase through the
WAIT input in synchronous mode:
•
At EBU_CLK edge 1 (at the end of the Address Phase), the EBU samples the WAIT
input as low and starts the first cycle of the Command Phase (CPi1 - internally
programmed).
•
At EBU_CLK edge 2, the EBU samples the WAIT input as low and starts an
additional Command Phase cycle (CPe2 - externally generated) as a result of the
WAIT input sampled as low at EBU_CLK edge 1.
•
At EBU_CLK edge 3, the EBU samples the WAIT input as high and starts an
additional Command Phase cycle (CPe3 - externally generated) as a result of the
WAIT input sampled as low at EBU_CLK edge 2.
•
Finally at EBU_CLK edge 4, as a result of the WAIT input sampled as high at point
3, the EBU terminates the Command Phase, reads the input data from D[31:0] and
starts the Recovery Phase.
Note: Synchronous operation means that even though access to the device may be
asynchronous, the control logic generating the control signals must meet setup
and hold time requirements with respect to EBU_CLK.
Содержание TC1784
Страница 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Страница 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Страница 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Страница 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
Страница 2350: ...w w w i n f i n e o n c o m Published by Infineon Technologies AG Doc_Number ...