ST40RA datasheet(20/94 Pages) STMICROELECTRONICS

20 / 94 page

ADCS 7260755H

STMicroelectronics

20/94

ST40RA

5 System configuration

NOTMACK

(Master)

EMI_BUS_GRANT EMI_BUS_GRANT EMI_BUS_GRANT MPX bus

acknowledge

MPX bus

acknowledge

FCLKOUT

FLASHCLOCK

NOTFBAA

Unconnected/

connectedb

NOTESCS0

MBXINT

NOTESCS1

EMPIDREQ0

NOTESCS2

EMPIDRAK0

a. When the EMI is configured in master mode (MODE9 = H), and an external slave DMA asks for

access to the bus (using NOTMACK or NOTMREQ), RFSH_PENDING and ACC_PENDING are

used to signal that, while the external DMA request has been granted and the DMA is using the bus,

a refresh time out occurred, or that the EMI has been asked for a new access. A bus arbiter, if

present, can use this information to give back the bus to the EMI to allow a refresh operation, or

improve bandwidth. When the EMI is in slave mode (MODE9 = L), RFSH_PENDING is always

deasserted (so EPENDING = ACC_PENDING), and the pin is used to signal to the external bus

arbiter that the EMI needs to use the bus.

b. NOTFBAA is an output of the ST40RA, and an input to the memory device. The pin must be left

unconnected from the ST40RA side and tied low at the memory device side if the memory is an Intel

or an STM part. It needs to be connected if the SFlash is an AMD.

ST40RA EMI pin

Peripheral

SFlash

SDRAM

MPX

MPX/EMPI

Table 8: EMI pin functions

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