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Serial Wombat Arduino Library
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A class for the Serial Wombat 4B or SW18AB chips which creates an I2C to UART Bridge. More...
#include <SerialWombatUART.h>
Public Member Functions | |
SerialWombatUART (SerialWombatChip &serialWombat) | |
Constructor for the SerialWombatUART class. Only one instance is allowed per SerialWombatChip 4B. More... | |
int16_t | begin (uint32_t baudRate, uint8_t pin, uint8_t rxPin, uint8_t txPin, uint8_t HWinterface=1) |
Initalize the SerialWombatUART. More... | |
int | available () |
Queries the SerialWombatUART for number bytes available to read. More... | |
int | read () |
Reads a byte from the SerialWombatUART. More... | |
void | flush () |
Discard all received bytes. More... | |
int | peek () |
Query the SerialWombatUART for the next avaialble byte, but don't remove it from the queue. More... | |
size_t | write (uint8_t data) |
Write a byte to the SerialWombatUART for Transmit. More... | |
size_t | write (const uint8_t *buffer, size_t size) |
Write bytes to the SerialWombatUART for Transmit. More... | |
int | availableForWrite () |
Queries the SerialWombatUART for the amount of free TX queue space. More... | |
size_t | readBytes (char *buffer, size_t length) |
Reads a specified number of bytes from the SerialWombatUART RX queue. More... | |
void | setTimeout (long timeout_mS) |
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SerialWombatPin (SerialWombatChip &serialWombatChip) | |
Instantiates a Serial Wombat Pin. More... | |
SerialWombatPin (SerialWombatChip &serialWombatChip, uint8_t pin) | |
Instantiates a Serial Wombat Pin. More... | |
uint16_t | readPublicData () |
Read the 16 Bit public data associated with this pin. More... | |
void | pinMode (uint8_t mode) |
Set pin to INPUT or OUTPUT. More... | |
void | pinMode (uint8_t mode, bool pullDown, bool openDrain) |
Set pin to INPUT or OUTPUT, with options for pull Ups and open Drain settings. More... | |
void | digitalWrite (uint8_t val) |
Set output pin High or Low. More... | |
int | digitalRead () |
Reads the state of the Pin. More... | |
uint16_t | writePublicData (uint16_t value) |
Write a 16 bit value to this pin. More... | |
uint8_t | pin () |
Returns the current SW pin number. Used primarily for virtual calls by derived classes. More... | |
uint8_t | swPinModeNumber () |
Returns the Mode number. Used primarily by derived classes to populate packet data. More... | |
Protected Attributes | |
uint8_t | _rxPin = 255 |
uint8_t | _txPin = 255 |
uint8_t | _baudMarker = 0 |
uint32_t | timeout = 5000 |
uint8_t | _pinMode = PIN_MODE_UART_RX_TX |
uint8_t | _tx7Command = (uint8_t)SerialWombatCommands::COMMAND_UART0_TX_7BYTES |
uint8_t | _rx7Command = (uint8_t)SerialWombatCommands::COMMAND_UART0_RX_7BYTES |
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uint8_t | _pin = 255 |
SerialWombatChip & | _sw |
uint8_t | _pinMode = 0 |
A class for the Serial Wombat 4B or SW18AB chips which creates an I2C to UART Bridge.
This class allows use of the Serial Wombat 4B chips's internal UART hardware to send and receive data at standard baud rates in 8-N-1 format.
A Tutorial video is avaialble:
The class inherits from the Arduino Sream class, so functions such as println() can be used once the UART is initialized.
The Serial Wombat 4B chip has a 64 byte transmit buffer and 128 byte receive buffer. Therefore, up to 64 bytes can be sent to the SerialWombatUART at a time. Attempts to send more than that will result in the write, print, etc command blocking until space is available on the SerialWombatUART to buffer the data.
Received data is buffered on the Serial Wombat chip until it is retreived from the host.
To minimize this possiblity, read data frequently from the Serial Wombat chip, and set I2C frequency to 400kHz to maximize throughput (SW4B only) .
This class can Send, Receive, or both. A single instance of this class is allowed per Serial Wombat 4B chip due to the fact that it relies on the PIC16F15214's UART module, of which there is only one on the micro.
Two instances of this class can be used on the Serial Wombat 18AB chip by using the begin() call which takes a hardware indicator of 0 or 1.
A full Serial Wombat packet send / receive sequence (8 bytes in each direction) over I2C is necessary to query the status of the queues or to read or receive a byte of data.
The protocol becomes more efficient if multiple bytes are read or written using the readBytes or write(const uint8_t* buffer, size_t size) interfaces rather than read() or write(uint8_t data).
The class must be assigned to a pin. This may be either the receive or transmit pin.
Pin 0 on the Serial Wombat 4B is suggested as a receive pin as it has only input capability.
Serial Wombat 18AB pins must be enhanced digital performance pins.
Available baud rates are:
SerialWombatUART::SerialWombatUART | ( | SerialWombatChip & | serialWombat | ) |
Constructor for the SerialWombatUART class. Only one instance is allowed per SerialWombatChip 4B.
serialWombat | The Serial Wombat chip on which the SerialWombatUART instance will run. |
int SerialWombatUART::available | ( | ) |
Queries the SerialWombatUART for number bytes available to read.
int SerialWombatUART::availableForWrite | ( | ) |
Queries the SerialWombatUART for the amount of free TX queue space.
int16_t SerialWombatUART::begin | ( | uint32_t | baudRate, |
uint8_t | pin, | ||
uint8_t | rxPin, | ||
uint8_t | txPin, | ||
uint8_t | HWinterface = 1 |
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Initalize the SerialWombatUART.
baudRate | 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 |
pin | The pin that will host the state machine. This can be either the rxPin or txPin |
rxPin | The pin that will receive. All 4 pins on the SW4B may be used. 255 if no receive function is needed |
txPin | The pin that will transmit. Valid values for the SW4B are 1-3. 255 if no transmit function is needed |
HWinterface | 1 or 2 for HW UART 1 or 2 |
void SerialWombatUART::flush | ( | ) |
Discard all received bytes.
int SerialWombatUART::peek | ( | ) |
Query the SerialWombatUART for the next avaialble byte, but don't remove it from the queue.
int SerialWombatUART::read | ( | ) |
Reads a byte from the SerialWombatUART.
size_t SerialWombatUART::readBytes | ( | char * | buffer, |
size_t | length | ||
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Reads a specified number of bytes from the SerialWombatUART RX queue.
buffer | An array into which to put received bytes |
length | The maximum number of bytes to be received |
This function will read bytes from the SerialWombatUART RX queue into buffer. If 'length' characters are not available to read then the value returned will be less than length.
void SerialWombatUART::setTimeout | ( | long | timeout_mS | ) |
size_t SerialWombatUART::write | ( | const uint8_t * | buffer, |
size_t | size | ||
) |
Write bytes to the SerialWombatUART for Transmit.
buffer | An array of uint8_t bytes to send |
size | the number of bytes to send |
This function queries the SerialWombatUART for avaialble TX buffer space, and sends bytes as buffer space is avaialble. If avaialable buffer space is not sufficient to send the entire array then the function will block and continue trying until the entire message has been sent to the SerialWombatUART transmit queue.
size_t SerialWombatUART::write | ( | uint8_t | data | ) |
Write a byte to the SerialWombatUART for Transmit.
data | Byte to write |
This does not check to see if space is avaialble in order to improve perfomance . This isn't an issue at high baud rates, as overhead to transmit one byte at a time allows sufficent time for queuing data to be sent by the UART. This could be a problem at very low baud rates and high I2C bus speeds.
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