Initialization and Configuration
1097
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
External Peripheral Interface (EPI)
In quad chip select mode (CSCFGEXT is 0x1 and CSCFG is 0x1 or 0x2 in the EPIHBnCFG2 register),
both the peripheral and the memory space must be enabled. In the EPIADDRMAP register, the EPADR
field is 0x3, the ERADR field is 0x3, and the ECADR field is 0x0. With this configuration, CS0n asserts for
the address range beginning at 0x6000.0000, CS1n asserts for 0x8000.0000, CS2n for 0xA000.0000, and
CS3n for 0xC000.0000.
gives a detailed explanation of chip select address range mappings
based on combinations of enabled peripheral and memory space.
NOTE:
Only one memory area can be mapped to a single chip select. Enabling multiple memory
areas for one chip select may produce unexpected results.
(1)
When CS0 and CS1 share address space, CS0 asserts when the MSB of the address is 0 and CS1, when the MSB of the
address is 1.
Table 16-4. Dual- and Quad- Chip Select Address Mappings
Chip Select
Mode
ERADR
EPADR
ECADR
CS0
(1)
CS1
CS2
CS3
Dual-chip
select
0x0
0x1 or 0x2
0x0
EPADR defined
address range
(0xA000.000 or
0xC000.0000)
EPADR defined
address range
(0xA000.000 or
0xC000.0000)
N/A
N/A
Dual-chip
select
0x1 or 0x2
0x0
0x0
ERADR defined
address range
(0x6000.000 or
0x8000.000)
ERADR defined
address range
(0x6000.000 or
0x8000.000)
N/A
N/A
Dual-chip
select
0x1 or 0x2
0x1 or 0x2
0x0
EPADR defined
address range
(0xA000.000 or
0xC000.0000)
ERADR defined
address range
(0x6000.000 or
0x8000.000)
N/A
N/A
Dual-chip
select
0x0
0x1 or 0x2
0x1
ECADR defined
address range
(0x1000.000)
EPADR defined
address range
(0xA000.0000 or
0xC000.0000)
N/A
N/A
Dual-chip
select
0x1 or 0x2
0x0
0x1
ECADR defined
address range
(0x1000.000)
ERADR defined
address range
(0x6000.000 or
0x8000.000)
N/A
N/A
Quad-chip
select
0x3
0x3
0x0
0x6000.0000
0x8000.0000
0xA000.0000
0xC000.0000
The MODE field of the EPIHBnCFGn registers configure the interface for the chip selects, which support
ADMUX or ADNOMUX. See
for details on which configuration register controls each chip
select. If the CSBAUD bit is clear, all chip selects are configured by the MODE bit field of the EPIHBnCFG
register.
If the CSBAUD bit in the EPIHBnCFG2 register is set in Dual-chip select mode, the 2 chip selects can use
different clock frequencies, wait states and strobe polarity. If the CSBAUD bit is clear, both chip selects
use the clock frequency, wait states, and strobe polarity defined for CS0n. Additionally, if the CSBAUD bit
is set, the two chip selects can use different interface modes. If any interface modes are programmed to
ADMUX, then dual chip select mode must include the ALE capability. In quad chip select mode, if the
CSBAUD bit in the EPIHBnCFG2 register is set, the 4 chip selects can use different clock frequencies,
wait states and strobe polarity. If the CSBAUD bit is clear, all chip selects use the clock frequency, wait
states, and strobe polarity defined for CS0n. If the CSBAUD bit is set, the four chip selects can use
different interface modes.