EPI Registers
1132
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
External Peripheral Interface (EPI)
16.5.6 EPIHB16CFG Register (Offset = 0x10) [reset = 0x0008FF00]
EPI Host-Bus 16 Configuration (EPIHB16CFG)
NOTE:
The MODE field in the EPICFG register determines which configuration register is accessed
for offsets 0x010 and 0x014.
To access EPIHB16CFG, the MODE field must be 0x3.
The Host Bus 16 sub-configuration register is activated when the HB16 mode is selected. The HB16 mode
supports muxed address/data (overlay of lower 16 address and all 16 data pins), separated address/data,
and address-less FIFO mode. Note that this register is reset when the MODE field in the EPICFG register
is changed. If another mode is selected and the HB16 mode is selected again, the values must be
reinitialized.
This mode is intended to support SRAMs, Flash memory (read), FIFOs, and CPLDs/FPGAs, and devices
with an MCU/HostBus slave or 16-bit FIFO interface support.
Refer to
for information on signal configuration controlled by this register and the
EPIHB16CFG2 register.
If less address pins are required, the corresponding AFSEL bit (
) should not be enabled so
the EPI controller does not drive those pins, and they are available as standard GPIOs.
EPI Host-Bus 16 Mode can be configured to use one to four chip selects with and without the use of ALE.
If an alternative to chip selects are required, a chip enable can be handled in one of three ways:
1. Manually control via GPIOs.
2. Associate one or more upper address pins to CE. Because CE is normally CEn, lower addresses are
not used. For example, if pins EPI0S27 and EPI0S26 are used for Device 1 and 0 respectively, then
address 0x68000000 accesses Device 0 (Device 1 has its CEn high), and 0x64000000 accesses
Device 1 (Device 0 has its CEn high). The pull-up behavior on the corresponding GPIOs must be
properly configured to ensure that the pins are disabled when the interface is not in use.
3. With certain SRAMs, the ALE can be used as CEn because the address remains stable after the ALE
strobe. The subsequent WRn or RDn signals write or read when ALE is low thus providing CEn
functionality.
EPIHB16CFG is shown in
and described in
Return to
Figure 16-35. EPIHB16CFG Register
31
30
29
28
27
26
25
24
CLKGATE
CLKGATEI
CLKINV
RDYEN
IRDYINV
RESERVED
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R-0x0
23
22
21
20
19
18
17
16
XFFEN
XFEEN
WRHIGH
RDHIGH
ALEHIGH
WRCRE
RDCRE
BURST
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x1
R/W-0x0
R/W-0x0
R/W-0x0
15
14
13
12
11
10
9
8
MAXWAIT
R/W-0xFF
7
6
5
4
3
2
1
0
WRWS
RDWS
RESERVED
BSEL
MODE
R/W-0x0
R/W-0x0
R-0x0
R/W-0x0
R/W-0x0