NXP Semiconductors MKW01Z128, Справочное руководство

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31.3.6 SPI match register high (SPIx_MH)
Refer to the description of the ML register.
Address: Base a 5h offset
Bit 7 6 5 4 3 2 1 0
Read
Bits[15:8]
Write
Reset 0 0 0 0 0 0 0 0
SPIx_MH field descriptions
Field Description
Bits[15:8] Hardware compare value (high byte)
31.3.7 SPI Data Register low (SPIx_DL)
This register, together with the DH register, is both the input and output register for SPI
data. A write to the registers writes to the transmit data buffer, allowing data to be queued
and transmitted.
When the SPI is configured as a master, data queued in the transmit data buffer is
transmitted immediately after the previous transmission has completed.
The SPTEF bit in the S register indicates when the transmit data buffer is ready to accept
new data. When the transmit DMA request is disabled (TXDMAE is 0): The S register
must be read when S[SPTEF] is set before writing to the SPI data registers; otherwise, the
write is ignored. When the transmit DMA request is enabled (TXDMAE is 1) when
S[SPTEF] is set, the SPI data registers can be written automatically by DMA without
reading the S register first.
Data may be read from the SPI data registers any time after S[SPRF] is set and before
another transfer is finished. Failure to read the data out of the receive data buffer before a
new transfer ends causes a receive overrun condition, and the data from the new transfer
is lost. The new data is lost because the receive buffer still held the previous character
and was not ready to accept the new data. There is no indication for a receive overrun
condition, so the application system designer must ensure that previous data has been
read from the receive buffer before a new transfer is initiated.
In 8-bit mode, only the DL register is available. Reads of the DH register return all zeros.
Writes to the DH register are ignored.
Memory map/register definition
MKW01Z128 MCU Reference Manual, Rev. 3, 04/2016
592 Freescale Semiconductor, Inc.