• Interrupts – Each transmit and receive port generates an
interrupt upon completing the transfer of a data-word or
after transferring an entire data buffer or buffers
through DMA.
• Multichannel capability – Each SPORT supports 128 chan-
nels out of a 1,024-channel window and is compatible with
the H.100, H.110, MVIP-90, and HMVIP standards.
An additional 250 mV of SPORT input hysteresis can be
enabled by setting Bit 15 of the PLL_CTL register. When this bit
is set, all SPORT input pins have the increased hysteresis.
• DMA (direct memory access) – The DMA controller trans-
fers both transmit and receive data. This reduces the
number and frequency of interrupts required to transfer
data to and from memory. The UART has two dedicated
DMA channels, one for transmit and one for receive. These
DMA channels have lower default priority than most DMA
channels because of their relatively low service rates.
The baud rate, serial data format, error code generation and sta-
tus, and interrupts for the UART port are programmable.
The UART programmable features include:
• Supporting bit rates ranging from (f
SCLK
/1,048,576) bits per
second to (f
SCLK
/16) bits per second.
• Supporting data formats from seven bits to 12 bits per
frame.
• Both transmit and receive operations can be configured to
generate maskable interrupts to the processor.
The UART port’s clock rate is calculated as:
f
SCLK
UART Clock Rate
= ----------------------------------------------
-
16
UART_Divisor
where the 16-bit UART_Divisor comes from the UART_DLH
register (most significant 8 bits) and UART_DLL register (least
significant 8 bits).
In conjunction with the general-purpose timer functions,
autobaud detection is supported.
The capabilities of the UART are further extended with support
for the Infrared Data Association (IrDA
®
) serial infrared physi-
cal layer link specification (SIR) protocol.
SERIAL PERIPHERAL INTERFACE (SPI) PORT
The ADSP-BF531/ADSP-BF532/ADSP-BF533 processors have
an SPI-compatible port that enables the processor to communi-
cate with multiple SPI-compatible devices.
The SPI interface uses three pins for transferring data: two data
pins (master output-slave input, MOSI, and master input-slave
output, MISO) and a clock pin (serial clock, SCK). An SPI chip
select input pin (SPISS) lets other SPI devices select the proces-
sor, and seven SPI chip select output pins (SPISEL7–1) let the
processor select other SPI devices. The SPI select pins are recon-
figured general-purpose I/O pins. Using these pins, the SPI port
provides a full-duplex, synchronous serial interface which sup-
ports both master/slave modes and multimaster environments.
The baud rate and clock phase/polarities for the SPI port are
programmable, and it has an integrated DMA controller, con-
figurable to support transmit or receive data streams. The SPI
DMA controller can only service unidirectional accesses at any
given time.
The SPI port clock rate is calculated as:
f
SCLK
SPI Clock Rate
= -----------------------------------
-
2
SPI_BAUD
where the 16-bit SPI_BAUD register contains a value of 2 to
65,535.
During transfers, the SPI port simultaneously transmits and
receives by serially shifting data in and out on its two serial data
lines. The serial clock line synchronizes the shifting and sam-
pling of data on the two serial data lines.
GENERAL-PURPOSE I/O PORT F
The ADSP-BF531/ADSP-BF532/ADSP-BF533 processors have
16 bidirectional, general-purpose I/O pins on Port F (PF15–0).
Each general-purpose I/O pin can be individually controlled by
manipulation of the GPIO control, status and interrupt
registers:
• GPIO direction control register – Specifies the direction of
each individual PFx pin as input or output.
• GPIO control and status registers – The processor employs
a “write one to modify” mechanism that allows any combi-
nation of individual GPIO pins to be modified in a single
instruction, without affecting the level of any other GPIO
pins. Four control registers are provided. One register is
written in order to set GPIO pin values, one register is writ-
ten in order to clear GPIO pin values, one register is written
in order to toggle GPIO pin values, and one register is writ-
ten in order to specify GPIO pin values. Reading the GPIO
status register allows software to interrogate the sense of
the GPIO pin.
• GPIO interrupt mask registers – The two GPIO interrupt
mask registers allow each individual PFx pin to function as
an interrupt to the processor. Similar to the two GPIO
control registers that are used to set and clear individual
GPIO pin values, one GPIO interrupt mask register sets
bits to enable interrupt function, and the other GPIO inter-
rupt mask register clears bits to disable interrupt function.
August 2013
UART PORT
The ADSP-BF531/ADSP-BF532/ADSP-BF533 processors pro-
vide a full-duplex universal asynchronous receiver/transmitter
(UART) port, which is fully compatible with PC-standard
UARTs. The UART port provides a simplified UART interface
to other peripherals or hosts, supporting full-duplex, DMA-sup-
ported, asynchronous transfers of serial data. The UART port
includes support for 5 data bits to 8 data bits, 1 stop bit or 2 stop
bits, and none, even, or odd parity. The UART port supports
two modes of operation:
• PIO (programmed I/O) – The processor sends or receives
data by writing or reading I/O-mapped UART registers.
The data is double-buffered on both transmit and receive.
Rev. I
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