Texas Instruments TM4C1294NCPDT User Manual

used as GPIOs or for other functions. For example, when using a 4-bit address with an 8-bit
data, the pins assigned to EPIS0[23:8] can be assigned to other functions.
■ Data may be 8 bits, 16 bits, 24 bits, or 32 bits (controlled by the DSIZE field in the EPIGPCFG
register). By default, the EPI controller uses data bits [7:0] when the DSIZE field in the EPIGPCFG
register is 0x0; data bits [15:0] when the DSIZE field is 0x1; data bits [23:0] when the DSIZE
field is 0x2; and data bits [31:0] when the DSIZE field is 0x3.32-bit data cannot be used with
address or EPI clock or any other signal. 24-bit data can only be used with 4-bit address or no
address.
■ When using the EPI controller as a GPIO interface, writes are FIFOed (up to 4 can be held at
any time), and up to 32 pins are changed using the EPIBAUD clock rate specified by COUNT0.
As a result, output pin control can be very precisely controlled as a function of time. By contrast,
when writing to normal GPIOs, writes can only occur 8-bits at a time and take up to two clock
cycles to complete. In addition, the write itself may be further delayed by the bus due to μDMA
or draining of a previous write. With both GPIO and the EPI controller, reads may be performed
directly, in which case the current pin states are read back. With the EPI controller, the
non-blocking interface may also be used to perform reads based on a fixed time rule via the
EPIBAUD clock rate.
Table 11-12 on page 849 shows how the EPI0S[31:0] signals function while in General-Purpose
mode. Notice that the address connections vary depending on the data-width restrictions of the
external peripheral.
Table 11-12. EPI General-Purpose Signal Connections
General- Purpose
Signal (D32)
General- Purpose
Signal (D24, A4)
General- Purpose
Signal (D16, A12)
General-Purpose
Signal (D8, A20)
EPI Signal
D0D0D0D0EPI0S0
D1D1D1D1EPI0S1
D2D2D2D2EPI0S2
D3D3D3D3EPI0S3
D4D4D4D4EPI0S4
D5D5D5D5EPI0S5
D6D6D6D6EPI0S6
D7D7D7D7EPI0S7
D8D8D8A0EPI0S8
D9D9D9A1EPI0S9
D10D10D10A2EPI0S10
D11D11D11A3EPI0S11
D12D12D12A4EPI0S12
D13D13D13A5EPI0S13
D14D14D14A6EPI0S14
D15D15D15A7EPI0S15
D16D16A0
a
A8EPI0S16
D17D17A1A9EPI0S17
D18D18A2A10EPI0S18
D19D19A3A11EPI0S19
D20D20A4A12EPI0S20
849June 18, 2014
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TM4C1294NCPDT Microcontroller

Texas Instruments TM4C1294NCPDT Specifications

General

Brand	Texas Instruments
Model	TM4C1294NCPDT
Category	Microcontrollers
Language	English