TM4C1292NCPDT Datasheet, PDF (873/1822 Pages) Texas Instruments – Tiva Microcontroller

Tiva^™ TM4C1292NCPDT Microcontroller
Bit/Field
27
Name
CSCFGEXT
Type
RW
Reset
0
Description
Chip Select Extended Configuration
This field is used in conjunction with CSCFG, to extend the chip select
options, and ALE format. The values 0x0 through 0x3 are from the
CSCFG field. The CSCFGEXT bit extends the values to 0x7.
Value Description
0 CSCFG bit field is used in chip select configuration.
1 The CSCFG bit field is extended with CSCFGEXT representing
the MSB.
The possible chip select configurations when the CSCFGEXT bit is
enabled are shown below:
Table 11-14. CSCFGEXT + CSCFG Encodings
Value
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
Description
ALE Configuration
EPI0S30 is used as an address latch (ALE). The ALE signal
is generally used when the address and data are muxed (MODE
field in the EPIHB8CFG register is 0x0). The ALE signal is
used by an external latch to hold the address through the bus
cycle.
CSn Configuration
EPI0S30 is used as a Chip Select (CSn). When using this
mode, the address and data are generally not muxed (MODE
field in the EPIHB8CFG register is 0x1). However, if address
and data muxing is needed, the WR signal (EPI0S29) and the
RD signal (EPI0S28) can be used to latch the address when
CSn is low.
Dual CSn Configuration
EPI0S30 is used as CS0n and EPI0S27 is used as CS1n.
Whether CS0n or CS1n is asserted is determined by the most
significant address bit for a respective external address map.
This configuration can be used for a RAM bank split between
2 devices as well as when using both an external RAM and
an external peripheral.
ALE with Dual CSn Configuration
EPI0S30 is used as address latch (ALE), EPI0S27 is used
as CS1n, and EPI0S26 is used as CS0n. Whether CS0n or
CS1n is asserted is determined by the most significant
address bit for a respective external address map.
ALE with Single CSn Configuration
EPI0S30 is used as address latch (ALE) and EPI0S27 is
used as CSn.
Quad CSn Configuration
EPI0S30 is used as CS0n and EPI0S27 is used as CS1n.
EPI0S34 is used as CS2n and EPI0S33 is used as CS3n.
ALE with Quad CSn Configuration
EPI0S30 is used as ALE, EPI0S26 is CS0n, and EPI0S27
is used as CS1n. EPI0S34 is used as CS2n and EPI0S33 is
used as CS3n.
Reserved
June 18, 2014
873
Texas Instruments-Production Data