EZ80F91MCU ZILOG [Zilog, Inc.], EZ80F91MCU Datasheet - Page 233

• Manufacturer Part Number: EZ80F91MCU
• Description: eZ80Acclaim-TM Flash Microcontrollers
• Manufacturer: ZILOG [Zilog, Inc.]

PS019209-0504
Data Transfer Procedure with SPI Configured as a Master
Data Transfer Procedure with SPI Configured as a Slave
SPI Registers
The SPI Data Rate can be calculated using the following equation:
Upon RESET, the 16-bit BRG divisor value resets to
ating as a Master, the BRG divisor value must be set to a value of
greater. When the SPI is operating as a Slave, the BRG divisor value must be set
to a value of
registers for the BRG Divisor Latch causes both the Low and High bytes to load
into the BRG counter, and causes the count to restart.
The sequence that follows details the procedure for transferring data from a mas-
ter SPI device to a slave SPI device.
1. Load the SPI Baud Rate Generator Registers, SPI_BRG_H and SPI_BRG_L.
2. Load the SPI Control Register, SPI_CTL.
3. Assert the ENABLE pin of the slave device using a GPIO pin.
4. Load the SPI Transmit Shift Register, SPI_TSR.
5. When the SPI data transfer is complete, deassert the ENABLE pin of the slave
The sequence that follows details the procedure for transferring data from a slave
SPI device to a master SPI device.
1. Load the SPI Baud Rate Generator Registers, SPI_BRG_H and SPI_BRG_L.
2. Load the SPI Transmit Shift Register, SPI_TSR. This load cannot occur while
3. Wait for the external SPI Master device to initiate the data transfer by
There are six registers in the Serial Peripheral Interface that provide control, sta-
tus, and data storage functions. The SPI registers are described in the following
paragraphs.
The external device must deassert the SS pin if currently asserted.
device.
the SPI slave is currently receiving data.
asserting SS.
SPI Data Rate (bits/s)
0004h
or greater. A software Write to either the Low- or High-byte
P R E L I M I N A R Y
=
2 X SPI Baud Rate Generator Divisor
System Clock Frequency
0002h
Product Specification
. When the SPI is oper-
Serial Peripheral Interface
0003h
eZ80F91 MCU
or
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