This class supports SPI bus controller mode, with blocking transfers.
SPI device numbers start at 0, to comply with the pinout of the Teensy
boards. With the configured clock frequency the fastest baud rate is
33MHz. For messages longer 16 bytes DMA is used. The class uses the
existing framework with extmod/machine_spi.c.
Extended driver options:
- drive=n with n being between 1 and 6 or PIN.POWER_1 to PIN.POWER_6.
Since the pins used by the SPI are fixed, no Pin settings can be made.
Thus the drive option is added allowing to control ringing and crosstalk
on the connection.
- gap_ns=nnnnn is the time between sent data items in a frame given in ns.
Default is 2 clock cycles.
The implementation uses the LPUARTx devices. Up to 8 UARTs can be used,
given that the pins are accessible. E.g. 8 on Teensy 4.1, 5 on
MIMXRT1020_EVK.
For Tennsy 4.0 and 4.1 the UART numbers are as printed on the pinout 1..N.
The MIMXRT10xx-EVK boards have only one UART named, which gets the number
1. All other UART are assigned to different Pins:
MIMXRT1010-EVK:
D0/D1 UART 1
D6/D7 UART 2
A0/D4 UART 3
MIMXRT1020-EVK:
D0/D1 UART 1
D6/D9 UART 2
D10/D12 UART 3
D14/D15 UART 4
A0/A1 UART 5
MIMXRT1050-EVK, MIMXRT1060-EVK, MIMXRT1064-EVK:
D0/D1 UART 1
D7/D6 UART 2
D8/D9 UART 3
A1/A0 UART 4
Initial version, using the LP RTC clock. It provides setting the date and
time with rtc.init() or rtc.datetime(), and reading the date and time with
rtc.datetime() or rtc.now(). The method weekday() reports the weekday of
the current date. It starts with 0 for Monday.
The tuple order for datetime() and now() matches the CPython sequence:
(year, month, day, hour, minute, second, microsecond, TZ). TZ is ignored
and reported as None. Microsecond is provided at a best effort.
If a battery is not supplied, the default boot date/time is 1970/1/1 0:0:0.
With a battery, the clock continues to run even when the board is not
powered. The clock is quite precise. If not, using rtc.calibration() may
help.
It supports three hardware timer channels based on the PIT timers of the
MIMXRT MCU. The timer id's are 0, 1 and 2. On soft reboot all active
timers will be stopped via finalisers.
