usb_iss package¶
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class
usb_iss.
UsbIss
(dummy=False, verbose=False)[source]¶ Bases:
object
Main object used to interact with the USB_ISS device.
Example
from usb_iss import UsbIss, defs # Configure I2C mode iss = UsbIss() iss.open("COM3") iss.setup_i2c() # Write and read back some data # NOTE: I2C methods use 7-bit device addresses (0x00 - 0x7F) iss.i2c.write(0x62, 0, [0, 1, 2]); data = iss.i2c.read(0x62, 0, 3) print(data) # [0, 1, 2]
- Parameters
dummy (bool) – Use a dummy driver stub, for testing.
verbose (bool) – Print debug output to the console.
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serial
¶ Attribute to use for Serial UART access. See
serial_.Serial
for the full set of Serial methods.- Type
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open
(port)[source]¶ Open the specified serial port for communication with the USB_ISS module.
- Parameters
port (str) – Serial port to use for usb_iss communication.
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setup_i2c
(clock_khz=400, use_i2c_hardware=True, io1_type=None, io2_type=None)[source]¶ Issue an ISS_MODE command to set the operating mode to I2C + IO.
- Parameters
clock_khz (int) – I2C clock rate in kHz. See https://www.robot-electronics.co.uk/htm/usb_iss_tech.htm for a list of valid values.
use_i2c_hardware (bool) – Use the USB_ISS module’s hardware I2C controller.
io1_type (defs.IOType) – IO1 mode (or None for no change)
io2_type (defs.IOType) – IO2 mode (or None for no change)
-
setup_i2c_serial
(clock_khz=400, use_i2c_hardware=True, baud_rate=9600)[source]¶ Issue an ISS_MODE command to set the operating mode to I2C + Serial.
- Parameters
clock_khz (int) – I2C clock rate in kHz. See https://www.robot-electronics.co.uk/htm/usb_iss_tech.htm for a list of valid values.
use_i2c_hardware (bool) – Use the USB_ISS module’s hardware I2C controller.
baud_rate (int) – Baud rate for the serial interface.
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setup_spi
(spi_mode=<SPIMode.TX_ACTIVE_TO_IDLE_IDLE_LOW: 144>, clock_khz=500)[source]¶ Issue an ISS_MODE command to set the operating mode to SPI.
- Parameters
spi_mode (defs.SPIMode) – SPI mode option to use.
clock_khz (int) – SPI clock rate in kHz.
-
setup_io
(io1_type=None, io2_type=None, io3_type=None, io4_type=None)[source]¶ Issue an ISS_MODE command to set the operating mode to IO.
- Parameters
io1_type (defs.IOType) – IO1 mode (or None for no change)
io2_type (defs.IOType) – IO2 mode (or None for no change)
io3_type (defs.IOType) – IO3 mode (or None for no change)
io4_type (defs.IOType) – IO4 mode (or None for no change)
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change_io
(io1_type=None, io2_type=None, io3_type=None, io4_type=None)[source]¶ Issue an ISS_MODE command to change the current IO mode without affecting serial or I2C settings.
- Parameters
io1_type (defs.IOType) – IO1 mode (or None for no change)
io2_type (defs.IOType) – IO2 mode (or None for no change)
io3_type (defs.IOType) – IO3 mode (or None for no change)
io4_type (defs.IOType) – IO4 mode (or None for no change)
-
setup_serial
(baud_rate=9600, io3_type=None, io4_type=None)[source]¶ Issue an ISS_MODE command to set the operating mode to Serial + IO.
- Parameters
baud_rate (int) – Baud rate for the serial interface.
io3_type (defs.IOType) – IO3 mode (or None for no change)
io4_type (defs.IOType) – IO4 mode (or None for no change)
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exception
usb_iss.
UsbIssError
[source]¶ Bases:
Exception
Raised when an error condition is detected by the usb_iss library.
usb_iss.i2c module¶
-
class
usb_iss.i2c.
I2C
(drv)[source]¶ Bases:
object
Use the USB_ISS device to perform I2C accesses.
Example
from usb_iss import UsbIss, defs # Configure I2C mode iss = UsbIss() iss.open("COM3") iss.setup_i2c() # Write and read back some data # NOTE: I2C methods use 7-bit device addresses (0x00 - 0x7F) iss.i2c.write(0x62, 0, [0, 1, 2]); data = iss.i2c.read(0x62, 0, 3) print(data) # [0, 1, 2]
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write
(address, register, data)[source]¶ Write multiple bytes to a device with a one-byte internal register address. This is an alias for the write_ad1 method, used by the majority of devices.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to write (0x00 - 0xFF).
data (list of int) – List of bytes to write to the device.
-
read
(address, register, byte_count)[source]¶ Read multiple bytes from a device with a one-byte internal register address. This is an alias for the read_ad1 method, used by the majority of devices.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to read (0x00 - 0xFF).
byte_count (int) – Number of bytes to read.
- Returns
List of bytes read from the device.
- Return type
list of int
-
write_single
(address, data_byte)[source]¶ Write a single byte to an I2C device.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
data_byte (int) – Data byte to write to the device.
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read_single
(address)[source]¶ Read a single byte from an I2C device.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
- Returns
Data byte read from the device.
- Return type
int
-
write_ad0
(address, data)[source]¶ Write multiple bytes to a device without internal register addressing, or where the internal register address does not require resetting.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
data (list of int) – List of bytes to write to the device.
-
read_ad0
(address, byte_count)[source]¶ Read multiple bytes from a device without internal register addressing, or where the internal register address does not require resetting.
- Parameters
address (int) – 7-bit I2C address of the device.
byte_count (int) – Number of bytes to read.
- Returns
List of bytes read from the device.
- Return type
list of int
-
write_ad1
(address, register, data)[source]¶ Write multiple bytes to a device with a one-byte internal register address.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to write (0x00 - 0xFF).
data (list of int) – List of bytes to write to the device.
-
read_ad1
(address, register, byte_count)[source]¶ Read multiple bytes from a device with a one-byte internal register address.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to read (0x00 - 0xFF).
byte_count (int) – Number of bytes to read.
- Returns
List of bytes read from the device.
- Return type
list of int
-
write_ad2
(address, register, data)[source]¶ Write multiple bytes to a device with a two-byte internal register address.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to write (0x0000 - 0xFFFF).
data (list of int) – List of bytes to write to the device.
-
read_ad2
(address, register, byte_count)[source]¶ Read multiple bytes from a device with a two-byte internal register address.
- Parameters
address (int) – 7-bit I2C address of the device (0x00 - 0x7F).
register (int) – Internal register address to read (0x0000 - 0xFFFF).
byte_count (int) – Number of bytes to read.
- Returns
List of bytes read from the device.
- Return type
list of int
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direct
(data)[source]¶ Send a custom I2C sequence to the device. See https://www.robot-electronics.co.uk/htm/usb_iss_i2c_tech.htm for a full set of examples.
- Parameters
data (list of defs.I2CDirect) – List of
I2CDirect
commands and data.- Returns
List of bytes read from the device.
- Return type
list of int
Example
# Equivalent to iss.i2c.write_single(0x20, 0x55) iss.i2c.direct([ defs.I2CDirect.START, defs.I2CDirect.WRITE2, 0x40, 0x55, defs.I2CDirect.STOP, ]);
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usb_iss.io module¶
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class
usb_iss.io.
IO
(drv)[source]¶ Bases:
object
Use the USB_ISS device to perform IO accesses.
Example
from usb_iss import UsbIss # Configure IO mode with all outputs low iss = UsbIss() iss.open("COM3") iss.setup_io(io1_type=defs.IOType.OUTPUT_LOW, io2_type=defs.IOType.OUTPUT_LOW, io3_type=defs.IOType.OUTPUT_LOW, io4_type=defs.IOType.OUTPUT_LOW) # Drive IO1 & IO3 high iss.io.set_pins(1, 0, 1, 0);
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set_pins
(io0, io1, io2, io3)[source]¶ Set the digital output pins high or low. This command only operates on pins that have been configured as digital outputs. Digital or analogue inputs or pins that are used for I2C or serial are not affected.
For each argument, set to 0 to drive low and 1 to drive high.
- Parameters
io0 (int) – IO0 output value.
io1 (int) – IO1 output value.
io2 (int) – IO2 output value.
io3 (int) – IO3 output value.
-
usb_iss.serial_ module¶
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class
usb_iss.serial_.
Serial
(drv)[source]¶ Bases:
object
Use the USB_ISS device to perform Serial UART accesses.
Example
from usb_iss import UsbIss # Configure Serial mode iss = UsbIss() iss.open("COM3") iss.setup_serial() # Write and read some data iss.serial.transmit([0x48, 0x65, 0x6c, 0x6c, 0x6f]); iss.serial.transmit_string("Hello!") data = iss.serial.receive() print(data) # [72, 105]
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transmit
(data)[source]¶ Transmit data over the Serial UART interface.
- Parameters
data (list of int) – List of bytes to transmit.
-
transmit_string
(string, encoding='utf-8')[source]¶ Transmit a string over the Serial UART interface.
- Parameters
string (str) – String to transmit.
encoding (str) – Encoding of the string.
-
receive
(timeout_ms=100)[source]¶ Receive data over the Serial UART interface. Returns once no data is received for timeout_ms.
- Parameters
timeout_ms (int) – Returns once no data is received for this period.
- Returns
List of bytes received.
- Return type
list of int
-
receive_string
(timeout_ms=100, encoding='utf-8')[source]¶ Receive a string over the Serial UART interface. Returns once no data is received for timeout_ms.
- Parameters
timeout_ms (int) – Returns once no data is received for this period.
encoding (str) – Encoding of the string.
- Returns
String received.
- Return type
string
-
usb_iss.spi module¶
-
class
usb_iss.spi.
SPI
(drv)[source]¶ Bases:
object
Use the USB_ISS device to perform SPI accesses.
Example
from usb_iss import UsbIss # Configure SPI mode iss = UsbIss() iss.open("COM3") iss.setup_spi() # Write and read some data in a single transfer data = iss.spi.transfer([0, 1, 2]); print(data) # [4, 5, 6]
usb_iss.defs module¶
Definitions from http://www.robot-electronics.co.uk/htm/usb_iss_tech.htm.
-
class
usb_iss.defs.
Command
[source]¶ Bases:
enum.Enum
Command code sent as the first byte.
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I2C_SGL
= 83¶
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I2C_AD0
= 84¶
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I2C_AD1
= 85¶
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I2C_AD2
= 86¶
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I2C_DIRECT
= 87¶
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I2C_TEST
= 88¶
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USB_ISS
= 90¶
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SPI
= 97¶
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SERIAL
= 98¶
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SET_PINS
= 99¶
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GET_PINS
= 100¶
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GET_AD
= 101¶
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-
class
usb_iss.defs.
SubCommand
[source]¶ Bases:
enum.Enum
Internal subcommand used with Command.USB_ISS.
-
ISS_VERSION
= 1¶
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ISS_MODE
= 2¶
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GET_SER_NUM
= 3¶
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-
class
usb_iss.defs.
Mode
[source]¶ Bases:
enum.Enum
USB-ISS module operating modes.
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IO_MODE
= 0¶
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IO_CHANGE
= 16¶
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I2C_S_20KHZ
= 32¶
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I2C_S_50KHZ
= 48¶
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I2C_S_100KHZ
= 64¶
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I2C_S_400KHZ
= 80¶
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I2C_H_100KHZ
= 96¶
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I2C_H_400KHZ
= 112¶
-
I2C_H_1000KHZ
= 128¶
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SPI_MODE
= 144¶
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SERIAL
= 1¶
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SERIAL_I2C_S_20KHZ
= 33¶
-
SERIAL_I2C_S_50KHZ
= 49¶
-
SERIAL_I2C_S_100KHZ
= 65¶
-
SERIAL_I2C_S_400KHZ
= 81¶
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SERIAL_I2C_H_100KHZ
= 97¶
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SERIAL_I2C_H_400KHZ
= 113¶
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SERIAL_I2C_H_1000KHZ
= 129¶
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class
usb_iss.defs.
IOType
[source]¶ Bases:
enum.Enum
IO configuration for a single pin.
-
OUTPUT_LOW
= 0¶
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OUTPUT_HIGH
= 1¶
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DIGITAL_INPUT
= 2¶
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ANALOGUE_INPUT
= 3¶
-
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class
usb_iss.defs.
SPIMode
[source]¶ Bases:
enum.Enum
SPI clock phase setting.
-
TX_ACTIVE_TO_IDLE_IDLE_LOW
= 144¶
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TX_ACTIVE_TO_IDLE_IDLE_HIGH
= 145¶
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TX_IDLE_TO_ACTIVE_IDLE_LOW
= 146¶
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TX_IDLE_TO_ACTIVE_IDLE_HIGH
= 147¶
-
-
class
usb_iss.defs.
I2CDirect
[source]¶ Bases:
enum.Enum
I2C_DIRECT commands.
-
START
= 1¶
-
RESTART
= 2¶
-
STOP
= 3¶
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NACK
= 4¶
-
READ1
= 32¶
-
READ2
= 33¶
-
READ3
= 34¶
-
READ4
= 35¶
-
READ5
= 36¶
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READ6
= 37¶
-
READ7
= 38¶
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READ8
= 39¶
-
READ9
= 40¶
-
READ10
= 41¶
-
READ11
= 42¶
-
READ12
= 43¶
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READ13
= 44¶
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READ14
= 45¶
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READ15
= 46¶
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READ16
= 47¶
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WRITE1
= 48¶
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WRITE2
= 49¶
-
WRITE3
= 50¶
-
WRITE4
= 51¶
-
WRITE5
= 52¶
-
WRITE6
= 53¶
-
WRITE7
= 54¶
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WRITE8
= 55¶
-
WRITE9
= 56¶
-
WRITE10
= 57¶
-
WRITE11
= 58¶
-
WRITE12
= 59¶
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WRITE13
= 60¶
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WRITE14
= 61¶
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WRITE15
= 62¶
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WRITE16
= 63¶
-
-
class
usb_iss.defs.
ResponseCode
[source]¶ Bases:
enum.Enum
First byte of a response. Note: For I2C: NACK = 0x00, ACK = Non-zero.
-
NACK
= 0¶
-
ACK
= 255¶
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