EPI Registers
1133
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
External Peripheral Interface (EPI)
Table 16-19. EPIHB16CFG Register Field Descriptions
Bit
Field
Type
Reset
Description
31
CLKGATE
R/W
0x0
Clock Gated A software application should only set the CLKGATE bit
when there are no pending transfers or no EPI register access has
been issued.
0x0 = The EPI clock is free running.
0x1 = The EPI clock is held low.
30
CLKGATEI
R/W
0x0
Clock Gated Idle Note that EPI0S32 is an iRDY signal if RDYEN is
set.
CLKGATEI is ignored if CLKPIN is 0 or if the COUNT0 field in the
EPIBAUD register is cleared.
0x0 = The EPI clock is free running.
0x1 = The EPI clock is output only when there is data to write or
read (current transaction); otherwise the EPI clock is held low.
29
CLKINV
R/W
0x0
Invert Output Clock Enable If operating in asynchronous mode,
CLKINV must be 0.
0x0 = No effect.
0x1 = Invert EPI clock to ensure the rising edge is centered for
outbound signal's setup and hold. Inbound signal is captured on
rising edge EPI clock.
28
RDYEN
R/W
0x0
Input Ready Enable
0x0 = No effect.
0x1 = An external ready (iRDY) can be used to control the
continuation of the current access. If this bit is set and the iRDY
signal (EPIS032) is low, the current access is stalled.
27
IRDYINV
R/W
0x0
Input Ready Invert
0x0 = No effect.
0x1 = Invert polarity of incoming external ready. If this bit is set and
the iRDY signal (EPIS032) is high the current access is stalled.
26-24
RESERVED
R
0x0
23
XFFEN
R/W
0x0
External FIFO FULL Enable
0x0 = No effect.
0x1 = An external FIFO full signal can be used to control write
cycles. If this bit is set and the FFULL signal is high, XFIFO writes
are stalled.
22
XFEEN
R/W
0x0
External FIFO EMPTY Enable
0x0 = No effect.
0x1 = An external FIFO empty signal can be used to control read
cycles. If this bit is set and the FEMPTY signal is high, XFIFO reads
are stalled.
21
WRHIGH
R/W
0x0
WRITE Strobe Polarity
0x0 = The WRITE strobe for CS0n is WRn (active Low).
0x1 = The WRITE strobe for CS0n is WR (active High).
20
RDHIGH
R/W
0x0
READ Strobe Polarity
0x0 = The READ strobe for CS0n is RDn (active Low).
0x1 = The READ strobe for CS0n is RD (active High).
19
ALEHIGH
R/W
0x1
ALE Strobe Polarity
0x0 = The address latch strobe for CS0n is ALEn (active Low).
0x1 = The address latch strobe for CS0n is ALE (active High).
18
WRCRE
R/W
0x0
PSRAM Configuration Register Write Used for PSRAM configuration
registers.
With WRCRE set, the next transaction by the EPI will be a write of
the CR bit field in the EPIHBPSRAM register to the configuration
register (CR) of the PSRAM.
The WRCRE bit will self clear once the write-enabled CRE access is
complete.
0x0 = No Action.
0x1 = Start CRE write transaction for CS0n.